Internal organs Flashcards
(1049 cards)
1
Q
What are the main boundaries of the oral cavity?
A
Roof – hard and soft palate; Floor – tongue and mylohyoid; Lateral walls – cheeks; Anterior – oral fissure; Posterior – oropharyngeal isthmus.
2
Q
What are the two regions of the oral cavity?
A
1) Oral vestibule (between teeth and lips/cheeks); 2) Oral cavity proper (enclosed by dental arches).
3
Q
What separates the oral cavity from the nasal cavity?
A
The hard and soft palate.
4
Q
What are three main functions of the oral cavity?
A
1) Food intake and initial digestion; 2) Speech production; 3) Secondary airway access
5
Q
What nerve innervates the upper oral cavity (palate, upper teeth)?
A
Maxillary nerve (CN V2).
6
Q
What nerve innervates the lower teeth and oral part of the tongue?
A
Mandibular nerve (CN V3).
7
Q
What nerve carries taste from the anterior 2/3 of the tongue?
A
Facial nerve (CN VII), via chorda tympani.
8
Q
What nerve provides parasympathetic innervation to oral glands?
A
Facial nerve (CN VII), traveling with branches of CN V.
9
Q
What provides sympathetic innervation in the oral cavity?
A
Fibers from T1 via the superior cervical ganglion, travel with CN V or blood vessels.
10
Q
Which nerve innervates the tongue muscles?
A
Hypoglossal nerve (CN XII), except palatoglossus (via vagus CN X).
11
Q
Which nerve innervates most soft palate muscles?
A
Vagus nerve (CN X), except tensor veli palatini (mandibular nerve, CN V3).
12
Q
Which nerve innervates the mylohyoid (floor of mouth)?
A
Mandibular nerve (CN V3).
13
Q
Which bones form the hard palate?
A
Palatine processes of the maxillae (anterior 2/3) and horizontal plates of the palatine bones (posterior 1/3).
14
Q
What are the incisive canals?
A
Openings behind the incisor teeth transmitting greater palatine vessels and nasopalatine nerves.
15
Q
What are the greater and lesser palatine foramina?
A
Openings in the palatine bones for greater and lesser palatine nerves and vessels (to palate and soft palate).
16
Q
Which bones form the structural base of the oral cavity?
A
Maxillae, palatine bones, mandible, sphenoid, temporal, and hyoid bones.
17
Q
What forms the V-shaped gap between the medial and lateral pterygoid plates?
A
The pyramidal process of the palatine bone fills this gap.
18
Q
What is the function of the pterygoid hamulus?
A
Acts as a pulley for the tensor veli palatini and an attachment for the pterygomandibular raphe.
19
Q
What attaches at the scaphoid fossa?
A
Tensor veli palatini muscle.
20
Q
Where are the sphenoid spines located, and what attaches there?
A
Posteromedial to the foramen spinosum; lateral part of the tensor veli palatini attaches here.
21
Q
What attaches to the styloid process?
A
Styloglossus muscle (tongue) and stylohyoid ligament.
22
Q
What attaches to the triangular roughened area anteromedial to the carotid canal?
A
Levator veli palatini muscle.
23
Q
Where is the cartilaginous part of the pharyngotympanic tube located?
A
Between the petrous temporal bone and greater wing of the sphenoid.
24
Q
What muscles relate to the auditory tube’s attachments?
A
Levator veli palatini is medial; tensor veli palatini attaches to the membranous lamina.
25
What are the superior and inferior mental spines?
Sites for attachment of tongue and geniohyoid muscles.
26
What is the mylohyoid line and what attaches there?
Ridge for mylohyoid muscle, forming the floor of the oral cavity.
27
What are the sublingual and submandibular fossae?
Depressions above and below the mylohyoid line for the sublingual and submandibular glands.
28
What passes through the mandibular foramen?
Inferior alveolar nerve and vessels.
29
What attaches to the retromolar triangle?
Pterygomandibular raphe, connecting to the buccinator and superior constrictor.
30
What are the parts of the hyoid bone?
Body, greater horns, and lesser horns.
31
What connects to the lesser horns of the hyoid?
Stylohyoid ligaments
32
Why is the hyoid bone important?
Links oral cavity, pharynx, and larynx.
33
What forms the muscular layer of the cheeks?
Buccinator muscle.
34
What is the origin and insertion of the buccinator muscle?
Origin: alveolar parts of maxilla and mandible, and pterygomandibular raphe; Insertion: modiolus and blends with orbicularis oris.
35
Which two muscles are connected by the pterygomandibular raphe?
Buccinator (anteriorly) and superior pharyngeal constrictor (posteriorly).
36
What is the function of the buccinator?
Keeps food between teeth during chewing and holds cheeks against the alveolar arches.
37
What provides general sensation to the cheek?
Buccal branch of the mandibular nerve (CN V3).
38
What forms the muscular diaphragm of the oral cavity floor?
The paired mylohyoid muscles.
39
What are the functions of the mylohyoid muscles?
Elevate the hyoid/larynx during swallowing, depress the mandible when hyoid is fixed, and support the floor of mouth.
40
What innervates the mylohyoid muscle?
Nerve to mylohyoid (branch of inferior alveolar nerve, from CN V3).
41
Where does the geniohyoid muscle run?
From inferior mental spines (mandible) to anterior body of hyoid bone.
42
What is the action of the geniohyoid muscle?
Elevates and pulls hyoid forward during swallowing; assists mouth opening if hyoid is fixed.
43
What innervates the geniohyoid?
C1 fibers via the hypoglossal nerve (CN XII).
44
What defines the oropharyngeal triangle?
Bounded by the posterior free border of mylohyoid, and the superior and middle constrictor muscles.
45
What key structures pass through the oropharyngeal triangle?
Hyoglossus, styloglossus, lingual artery and vein, lingual, glossopharyngeal (CN IX), and hypoglossal (CN XII) nerves, lymphatics, and the submandibular gland.
46
What anatomical regions divide the tongue?
The oral part (anterior 2/3) and the pharyngeal part (posterior 1/3), separated by the terminal sulcus.
47
What is the foramen cecum of the tongue?
A small depression at the apex of the terminal sulcus; marks embryologic origin of the thyroid gland.
48
Which bones anchor the root of the tongue?
Mandible and hyoid bone.
49
Which papillae are found on the oral part of the tongue and contain taste buds?
Fungiform, vallate, and foliate papillae (filiform are the only ones without taste buds).
50
Which papillae are arranged in a V-shape just anterior to the terminal sulcus?
Vallate papillae.
51
Where are foliate papillae located?
On the lateral sides of the tongue near the terminal sulcus.
52
What structure is formed by lymphoid nodules in the pharyngeal part of the tongue?
The lingual tonsil.
53
What structure connects the underside of the tongue to the floor of the mouth?
The lingual frenulum.
54
What structures lie lateral to the frenulum on the underside of the tongue?
Lingual veins and fimbriated folds.
55
What are the intrinsic muscles of the tongue?
Superior longitudinal, inferior longitudinal, transverse, and vertical muscles.
56
What is the function of intrinsic tongue muscles?
Alter shape of tongue (e.g., curling, flattening, shortening), essential for speech, swallowing, and eating.
57
What is unique about the intrinsic tongue muscles’ origin and insertion?
They are entirely within the tongue — no external bony attachments.
58
Which nerve innervates all tongue muscles except one?
Hypoglossal nerve (CN XII).
59
Which tongue muscle is NOT innervated by CN XII, and what innervates it?
Palatoglossus, innervated by the vagus nerve (CN X).
60
What are the four extrinsic muscles of the tongue?
Genioglossus, hyoglossus, styloglossus, palatoglossus.
61
What distinguishes extrinsic from intrinsic tongue muscles?
Extrinsic muscles originate outside and insert into the tongue, moving it as a whole. Intrinsic muscles are entirely within the tongue and alter its shape.
62
What is the origin of the genioglossus muscle?
Superior mental spines on the posterior surface of the mandibular symphysis.
63
What is the function of the genioglossus?
Depresses the center of the tongue and protrudes the anterior part (sticks tongue out).
64
Which nerve innervates the genioglossus?
Hypoglossal nerve (CN XII).
65
What clinical test involves the genioglossus?
Ask patient to stick out tongue — deviation indicates CN XII lesion on the same side.
66
Where does the hyoglossus muscle originate and insert?
From the greater horn and body of the hyoid bone to the lateral tongue (deep to styloglossus, lateral to genioglossus).
67
What is the function of the hyoglossus?
Depresses the tongue.
68
What neurovascular structures are related to the hyoglossus?
Deep to it: Lingual artery
Superficial to it: Hypoglossal nerve (XII) and lingual nerve (V3)
69
Where does the styloglossus originate and insert?
Originates from styloid process of temporal bone; inserts into lateral tongue blending with hyoglossus and intrinsic muscles.
70
What is the function of the styloglossus?
Retracts and elevates the posterior tongue.
71
What innervates the styloglossus?
Hypoglossal nerve (CN XII).
72
Where does the palatoglossus muscle originate and insert?
From the palatine aponeurosis to the lateral side of the tongue.
73
What is the function of the palatoglossus?
Elevates posterior tongue
Depresses soft palate
Closes oropharyngeal isthmus
74
What innervates the palatoglossus?
Vagus nerve (CN X) — only tongue muscle not innervated by CN XII.
75
What is the main arterial supply to the tongue?
The lingual artery, a branch of the external carotid artery.
76
What structures does the lingual artery supply?
Tongue, sublingual gland, gingiva, and oral mucosa of the floor.
77
Through which muscle plane does the lingual artery travel?
Between the hyoglossus and genioglossus muscles.
78
What are the two major veins of the tongue?
Deep lingual vein and dorsal lingual vein.
79
Where do the tongue’s veins drain?
Into the internal jugular vein.
80
Which nerve accompanies the deep lingual vein?
The hypoglossal nerve (XII) on the external surface of hyoglossus.
81
What part of the tongue does CN IX innervate?
Posterior 1/3 of tongue (pharyngeal part): taste + general sensation.
82
Does CN IX innervate the vallate papillae?
Yes — even though they lie anterior to the terminal sulcus.
83
What part of the tongue does the lingual nerve innervate?
Anterior 2/3 of tongue: general sensation.
84
What other oral structures does the lingual nerve supply?
Mucosa of the floor of mouth and gingiva of lower teeth.
85
What modality is carried by the chorda tympani?
Taste from the anterior 2/3 of the tongue (special afferent).
86
How does the facial nerve reach the tongue?
Through the chorda tympani, which joins the lingual nerve.
87
What does CN XII innervate?
All intrinsic and extrinsic muscles of the tongue, except palatoglossus.
88
Which muscle is the exception, and what innervates it?
Palatoglossus – innervated by the vagus nerve (CN X).
89
Which cervical spinal nerve travels with CN XII and what does it supply?
C1 fibers: supply geniohyoid and thyrohyoid.
90
Where does lymph from the tongue ultimately drain?
Into the deep cervical lymph nodes along the internal jugular vein.
91
Which node drains the posterior 1/3 (pharyngeal part)?
Mainly the jugulodigastric node.
92
Which nodes receive lymph from the anterior tongue?
Submental nodes (tip) → jugulo-omohyoid node
Submandibular nodes (lateral tongue/body) → deep cervical nodes
93
What are the three major paired salivary glands?
Parotid, submandibular, and sublingual glands.
94
Where are the minor salivary glands located?
In the submucosa/mucosa of the tongue, palate, cheeks, and lips.
95
Where is the parotid gland located?
Outside the oral cavity, in a trench bordered by the sternocleidomastoid, mandibular ramus, and zygomatic arch.
96
Through which path does the parotid duct travel?
Over the masseter, pierces buccinator, opens near 2nd upper molar.
97
What important structures pass through the parotid gland?
External carotid artery, retromandibular vein, facial nerve [VII].
98
Describe the shape and position of the submandibular gland.
Hook-shaped:
Superficial part: below mylohyoid, in submandibular fossa.
Deep part: loops around the mylohyoid, into the oral cavity floor.
99
Where does the submandibular duct open?
On the sublingual caruncle beside the base of the lingual frenulum.
100
What nerve crosses under the submandibular duct?
The lingual nerve (loops around it).
101
Where is the sublingual gland located?
In the floor of the oral cavity, medial to the mandible and lateral to the submandibular duct
102
What structure does it form in the floor of the mouth?
The sublingual fold.
103
How does it drain into the oral cavity?
Through multiple minor sublingual ducts along the fold; sometimes one major duct joins the submandibular duct.
104
What arteries supply the salivary glands?
Parotid: External carotid artery and its branches.
Submandibular & Sublingual: Facial and lingual arteries.
105
Into which veins do they drain?
Parotid: External jugular vein.
Others: Facial and lingual veins.
106
Where do their lymphatics drain?
Parotid: Parotid → superficial/deep cervical nodes.
Submandibular/Sublingual: Mainly submandibular nodes → deep cervical, esp. jugulo-omohyoid node.
107
Which nerve provides parasympathetic fibers to the parotid gland?
Glossopharyngeal nerve (CN IX) → otic ganglion → auriculotemporal nerve (CN V3).
108
Which branch of CN VII innervates submandibular & sublingual glands?
Chorda tympani, which joins the lingual nerve (CN V3).
109
Where do parasympathetic fibers to these glands synapse?
In the submandibular ganglion (appears to hang from the lingual nerve).
110
Which branch of CN VII innervates glands above the oral fissure and nasal/orbital mucus glands?
Greater petrosal nerve → pterygopalatine ganglion.
111
Where do sympathetic fibers to salivary glands originate and synapse?
Originate at T1 spinal cord, synapse at superior cervical ganglion.
112
How do sympathetic fibers reach the glands?
They travel along blood vessels and sometimes along cranial nerves.
113
What are the two parts of the palate forming the roof of the oral cavity?
The hard palate (anterior) and the soft palate (posterior).
114
What bones contribute to the hard palate?
The palatine processes of the maxillae (anterior 3/4) and horizontal plates of the palatine bones (posterior 1/4).
115
What structures are found on the oral mucosal surface of the hard palate?
Palatine rugae, palatine raphe, and the incisive papilla.
116
What is the function of the soft palate?
It acts as a valve, depressing to close the oropharyngeal isthmus and elevating to separate the nasopharynx from the oropharynx.
117
Which muscle forms the fibrous palatine aponeurosis and tenses the soft palate?
Tensor veli palatini.
118
Which nerve innervates the tensor veli palatini?
Mandibular nerve (CN V3) via the nerve to the medial pterygoid.
119
Which muscle elevates the soft palate and closes the pharyngeal isthmus?
Levator veli palatini.
120
What nerve innervates all soft palate muscles except the tensor veli palatini?
The vagus nerve (CN X) via the pharyngeal plexus.
121
What are the functions of the palatopharyngeus muscle?
Depresses the palate, draws arches medially, and elevates the pharynx during swallowing.
122
What muscle connects the soft palate to the tongue and helps close the oropharyngeal isthmus?
Palatoglossus.
123
What is the function of the musculus uvulae?
Elevates and retracts the uvula, thickening the central soft palate.
124
Which arteries supply the palate?
Greater palatine artery (maxillary), ascending palatine artery (facial), palatine branch (ascending pharyngeal), and lesser palatine artery.
125
What forms the roof of the oral cavity?
The hard and soft palates
→ The hard palate separates the oral and nasal cavities; the soft palate acts as a movable valve
126
What bones contribute to the hard palate?
The palatine processes of the maxillae (anterior ¾) and horizontal plates of the palatine bones (posterior ¼)
127
What is the function of the soft palate?
It helps close the oropharyngeal isthmus and separates the nasopharynx from the oropharynx when elevated
128
What muscle tenses the soft palate and opens the pharyngotympanic tube?
Tensor veli palatini
→ Innervated by the mandibular nerve [V3] via the nerve to the medial pterygoid
129
What muscle elevates the soft palate above neutral position?
Levator veli palatini
→ Innervated by the vagus nerve [X] through the pharyngeal plexus
130
What muscle depresses the soft palate and elevates the pharynx during swallowing?
Palatopharyngeus
→ Innervated by the vagus nerve [X] via the pharyngeal plexus
131
What muscle elevates the back of the tongue and depresses the soft palate?
Palatoglossus
→ Innervated by the vagus nerve [X] via the pharyngeal plexus
132
What muscle thickens the soft palate and retracts the uvula?
Musculus uvulae
→ Innervated by the vagus nerve [X] via the pharyngeal plexus
133
What is the main artery of the hard palate?
Greater palatine artery
→ Branch of the maxillary artery, travels through the greater palatine foramen and incisive canal
134
What arteries supply the soft palate?
Ascending palatine branch of the facial artery and palatine branch of the ascending pharyngeal artery
135
Where do veins from the palate drain?
Into the pterygoid venous plexus or veins around the palatine tonsil → draining into the pharyngeal plexus or facial vein
136
Where do lymphatics from the palate drain?
Into deep cervical lymph nodes
137
What nerves provide general sensation to the palate?
Greater and lesser palatine nerves and nasopalatine nerve
→ All are branches of the maxillary nerve [V2]
138
Which nerve carries taste and parasympathetic fibers to the palate?
Facial nerve [VII] via the greater petrosal nerve
139
What arteries supply the buccal gingiva of the lower teeth?
Branches of the inferior alveolar artery → Arises from the maxillary artery.
140
What arteries supply the lingual gingiva of the lower teeth?
Lingual artery branches → Supplies the side facing the tongue.
141
What arteries supply the buccal gingiva of the upper teeth?
Anterior and posterior superior alveolar arteries → Branches of the maxillary artery.
142
What arteries supply the palatal gingiva of the upper teeth?
Nasopalatine artery (incisors/canines) and greater palatine artery (premolars/molars) → Both from the maxillary artery.
143
What veins drain the lower teeth and gingivae?
Inferior alveolar veins, draining into the pterygoid venous plexus → Some anterior drainage via facial vein tributaries.
144
What veins drain the upper teeth and gingivae?
Superior alveolar veins → Drain into the pterygoid plexus.
145
How can infections from the teeth reach the cranial cavity
Through emissary veins connecting the pterygoid plexus to the cavernous sinus → Risk of intracranial spread.
146
Which vein also receives venous drainage via the mental foramen?
The facial vein → Connects with veins from the anterior mandible.
147
Where do lymphatics from the teeth and gingivae mainly drain?
Into submandibular, submental, and deep cervical lymph nodes.
148
Which nerve innervates all lower teeth?
Inferior alveolar nerve (from mandibular nerve V3) → Travels in mandibular canal.
149
What does the incisive branch of the inferior alveolar nerve innervate?
Incisors, canines, first premolar, and associated buccal gingiva.
150
What does the mental nerve innervate?
Chin and lower lip → Exits via mental foramen.
151
Which nerves innervate the upper teeth?
Anterior, middle, and posterior superior alveolar nerves → Branches of maxillary nerve V2.
152
What does the posterior superior alveolar nerve innervate?
Maxillary molar teeth → Enters maxilla via foramen on posterior maxilla.
153
What does the middle superior alveolar nerve supply?
Premolars → Branch of infraorbital nerve in infraorbital groove.
154
What does the anterior superior alveolar nerve supply?
Canines and incisors → Branch of infraorbital nerve in infraorbital canal.
155
What nerve innervates the buccal gingiva of upper teeth?
Anterior, middle, and posterior superior alveolar nerves.
156
What nerve innervates palatal gingiva of upper incisors and canines?
Nasopalatine nerve.
157
What nerve innervates palatal gingiva of upper premolars and molars?
Greater palatine nerve.
158
What innervates buccal gingiva of mandibular incisors, canines, and premolars?
Mental branch of inferior alveolar nerve.
159
What innervates buccal gingiva of mandibular molars?
Buccal nerve (from mandibular nerve V3).
160
What innervates lingual gingiva of all lower teeth?
Lingual nerve.
161
where are the anterior and posterior triangles of the neck
162
What is the pharynx?
A musculofascial half-cylinder connecting the nasal and oral cavities to the larynx and esophagus → Common pathway for air and food.
163
Where does the pharynx extend from and to?
From the base of the skull to vertebral level CVI, where it continues as the esophagus.
164
What are the three anatomical subdivisions of the pharynx?
Nasopharynx, oropharynx, and laryngopharynx → Based on anterior connections to nasal cavity, oral cavity, and larynx.
165
What opens into the nasopharynx?
The choanae (posterior nasal apertures) and pharyngotympanic (auditory) tubes.
166
What opens into the oropharynx?
The oropharyngeal isthmus (posterior opening of the oral cavity).
167
What opens into the laryngopharynx?
The laryngeal inlet (superior aperture of the larynx).
168
What lies anterior to the pharynx?
Posterior 1/3 of the tongue and posterior aspect of the larynx.
169
What lies posterior to the pharynx?
The vertebral column, separated by the retropharyngeal space (loose connective tissue).
170
What tonsils are associated with the pharynx?
Pharyngeal, palatine, and lingual tonsils → Positioned on the deep pharyngeal walls
171
What is the function of the soft palate in the pharynx?
It acts as a flutter valve:
Elevates to close the pharyngeal isthmus (separates nasopharynx from oropharynx)
Depresses to close the oropharyngeal isthmus (separates oral cavity from oropharynx)
172
Where do the superior margins of the pharynx attach?
To the base of the skull via a C-shaped line and to the pharyngeal tubercle (midline of occipital bone).
173
What structure joins the two sides of the pharynx posteriorly?
The pharyngeal raphe → A vertical connective tissue band from the pharyngeal tubercle to CVI.
174
What does the first part of the anterior pharyngeal wall attachment involve?
Medial pterygoid plate, pterygoid hamulus, and pterygomandibular raphe → Joins superior constrictor and buccinator muscles.
175
What is the second part of the attachment related to?
Stylohyoid ligament, lesser horn, and greater horn of the hyoid bone.
176
What structures are involved in the third (lowest) part of the pharyngeal wall attachment?
Thyroid cartilage (superior/inferior tubercles, oblique line), cricothyroid muscle, and cricoid cartilage.
177
What structures form the pharyngeal wall?
Skeletal muscles and fascia → Fascia reinforces gaps between muscles and allows passage of neurovascular structures
178
What are the two groups of pharyngeal muscles based on fiber orientation?
Constrictor muscles (circular) and longitudinal muscles (vertical).
179
What are the three constrictor muscles of the pharynx?
Superior, middle, and inferior constrictors → All attach posteriorly to the pharyngeal raphe.
180
What is the general action of the constrictor muscles?
Constrict the pharynx during swallowing to push the bolus downward → Sequential contraction from top to bottom.
181
What nerve innervates all constrictor muscles
Pharyngeal branch of the vagus nerve [X].
182
Where does the superior constrictor attach anteriorly?
Pterygoid hamulus, pterygomandibular raphe, and mandible.
183
What special muscle band blends with the superior constrictor?
Palatopharyngeal sphincter → Originates from soft palate, helps close the pharyngeal isthmus.
184
What are the anterior attachments of the middle constrictor?
Lower part of stylohyoid ligament, lesser horn, and upper surface of greater horn of hyoid bone.
185
Which constrictor overlaps the superior constrictor?
Middle constrictor.
186
Where does the inferior constrictor attach anteriorly?
Oblique line of thyroid cartilage, cricoid cartilage, and fascia over cricothyroid muscle.
187
What constrictor overlaps the middle constrictor?
Inferior constrictor.
188
What part of the pharynx does the inferior constrictor surround?
Narrowest part of the pharynx → Fibers attach to the esophageal wall.
189
What are the three longitudinal muscles of the pharynx?
Stylopharyngeus, salpingopharyngeus, and palatopharyngeus.
190
Where does the stylopharyngeus originate?
Styloid process of the temporal bone.
191
Where does the salpingopharyngeus originate?
Cartilaginous part of the pharyngotympanic tube.
192
Where does the palatopharyngeus originate?
Soft palate.
193
What is the function of the longitudinal muscles?
Elevate the pharyngeal wall during swallowing → Pull the wall over the food bolus.
194
Where does the stylopharyngeus muscle originate?
From the medial surface of the styloid process of the temporal bone.
195
Where does the stylopharyngeus insert?
Descends between the superior and middle constrictors, blending with the deep surface of the pharyngeal wall.
196
What is the function of the stylopharyngeus?
Elevates the pharynx during swallowing and speech
197
What nerve innervates the stylopharyngeus?
Glossopharyngeal nerve [IX] → The only pharyngeal muscle innervated by CN IX.
198
Where does the salpingopharyngeus originate?
From the inferior aspect of the pharyngotympanic (auditory) tube.
199
Where does the salpingopharyngeus insert?
Blends with the deep surface of the pharyngeal wall.
200
What is the function of the salpingopharyngeus?
Elevates the pharynx during swallowing; may also help open the auditory tube.
201
What nerve innervates the salpingopharyngeus
Vagus nerve [X].
202
Where does the palatopharyngeus originate?
From the upper surface of the palatine aponeurosis of the soft palate.
203
Where does the palatopharyngeus insert?
Descends to the deep surface of the pharyngeal wall, forming the palatopharyngeal arch.
204
What is the function of the palatopharyngeus?
Elevates the pharynx, depresses the soft palate, and closes the oropharyngeal isthmus during swallowing.
205
What nerve innervates the palatopharyngeus?
Vagus nerve [X].
206
What are the two layers of pharyngeal fascia?
Buccopharyngeal fascia (external) and pharyngobasilar fascia (internal).
207
What is the buccopharyngeal fascia?
A thin outer layer of fascia → Part of the pretracheal cervical fascia.
208
What is the pharyngobasilar fascia?
A thicker inner fascia lining the inside of the pharyngeal wall.
209
Where is the pharyngeal wall mainly formed of fascia?
Above the superior constrictor → Reinforced by tensor and levator veli palatini muscles of the soft palate.
210
What muscles and structures reinforce the pharyngeal wall above the superior constrictor?
Tensor and levator veli palatini muscles, passing through the pharyngeal fascia.
211
What does the levator veli palatini pass through to enter the soft palate?
Through the pharyngeal fascia, below the pharyngotympanic tube.
212
What does the tensor veli palatini tendon pass through?
It turns around the pterygoid hamulus and passes through the buccinator origin
213
What is the oropharyngeal triangle and what passes through it?
A gap between superior and middle constrictors and mylohyoid → Passage for stylopharyngeus, glossopharyngeal nerve, and tonsillar artery.
214
What passes through the gap between the middle and inferior constrictors?
Internal laryngeal nerve and superior laryngeal vessels → They pierce the thyrohyoid membrane
215
What passes below the inferior constrictor?
216
Where is the nasopharynx located?
Posterior to the choanae, above the soft palate → Continuous with the oropharynx at the pharyngeal isthmus.
217
What forms the roof of the nasopharynx?
Body of sphenoid and basilar part of occipital bone → Creates a domed vault.
218
How is the pharyngeal isthmus closed during swallowing?
By elevation of the soft palate and contraction of the palatopharyngeal sphincter.
219
What is the pharyngeal tonsil and what is it called when enlarged?
Lymphoid tissue in the roof of the nasopharynx → Called adenoids when enlarged.
220
What is the torus tubarius?
A mucosal bulge over the posterior rim of the pharyngotympanic tube opening.
221
What is the pharyngeal recess?
A deep mucosal pocket behind the torus tubarius.
222
What fold covers the salpingopharyngeus muscle?
Salpingopharyngeal fold.
223
What fold overlies the levator veli palatini muscle?
Torus levatorius.
224
Where is the oropharynx located?
Behind the oral cavity, below the soft palate, above the epiglottis.
225
What marks the boundary between oral cavity and oropharynx?
Palatoglossal folds → Define the oropharyngeal isthmus.
226
What folds lie just posterior to the palatoglossal folds?
Palatopharyngeal folds → Overlie palatopharyngeus muscles.
227
What forms the anterior wall of the oropharynx?
The posterior 1/3 of the tongue with lingual tonsils.
228
What are valleculae and where are they found?
Paired mucosal depressions between tongue and epiglottis.
229
What happens during swallowing in the oropharynx?
Soft palate elevates, larynx closes, oropharyngeal isthmus opens → Food is directed into the esophagus.
230
What are the borders of the laryngopharynx?
From the epiglottis to CVI, where it becomes the esophagus.
231
What opens into the anterior wall of the laryngopharynx?
The laryngeal inlet.
232
What are the piriform fossae and their function?
Mucosal recesses lateral to the larynx → Guide food around the laryngeal inlet into the esophagus.
233
What is Waldeyer’s ring?
A ring of lymphoid tissue surrounding the nasal and oral openings → Part of immune defense.
234
Where is the pharyngeal tonsil located?
In the roof of the nasopharynx → Known as adenoids when enlarged.
235
Where are the palatine tonsils located?
In the oropharynx, between the palatoglossal and palatopharyngeal arches.
236
Where are the lingual tonsils located?
On the posterior 1/3 of the tongue → Numerous small lymphoid nodules.
237
What other minor tonsillar tissues exist?
In the pharyngotympanic tube area and upper soft palate.
238
Which arteries supply the upper pharynx?
Branches of the external carotid artery, including:
Ascending pharyngeal artery
Ascending palatine and tonsillar branches of the facial artery
Branches of the maxillary and lingual arteries
239
Which artery supplies the lower pharynx?
Pharyngeal branches of the inferior thyroid artery → from the thyrocervical trunk of the subclavian artery.
240
What is the major artery supplying the palatine tonsil?
Tonsillar branch of the facial artery → Pierces the superior constrictor.
241
How is venous blood drained from the pharynx?
Through the pharyngeal venous plexus → Drains superiorly into the pterygoid plexus, and inferiorly into the facial and internal jugular veins.
242
Where do lymphatics from the pharynx drain?
Into deep cervical lymph nodes, including:
Retropharyngeal nodes (nasopharynx)
Paratracheal nodes
Infrahyoid nodes
243
Where do the palatine tonsils drain?
Into the jugulodigastric node → Located near the facial vein/internal jugular vein junction and posterior belly of digastric.
244
What is the main motor nerve to the pharynx?
Vagus nerve [X] via the pharyngeal plexus.
245
Which pharyngeal muscle is not innervated by the vagus nerve?
Stylopharyngeus → Innervated by glossopharyngeal nerve [IX].
246
What nerves contribute to the pharyngeal plexus?
Pharyngeal branch of the vagus [X] (motor)
External laryngeal nerve (from superior laryngeal branch of vagus)
Pharyngeal branches of glossopharyngeal [IX]
247
What innervates the nasopharynx?
Pharyngeal branch of maxillary nerve [V2] → Via palatovaginal canal.
248
What innervates the oropharynx?
Glossopharyngeal nerve [IX] → Through the pharyngeal plexus.
249
What innervates the laryngopharynx?
Vagus nerve [X] → Via the internal branch of the superior laryngeal nerve.
250
Through which foramen does CN IX exit the skull?
Jugular foramen.
251
What path does CN IX take to reach the pharynx and tongue?
Descends on and then crosses the stylopharyngeus, passes through the oropharyngeal triangle, and reaches the posterior tongue.
252
What pharyngeal structures does the glossopharyngeal nerve supply?
Motor to stylopharyngeus
Sensory to oropharynx and palatine tonsil
253
What is the afferent limb of the gag reflex?
Glossopharyngeal nerve [IX]
254
What is the larynx?
A musculoligamentous structure with cartilaginous framework → Caps the lower respiratory tract and produces sound.
255
What are the main functions of the larynx?
Acts as a valve (sphincter) to close the airway and as a voice organ (phonation).
256
What is the larynx continuous with above and below?
Above: Opens into the pharynx; Below: Continuous with the trachea.
257
What is the larynx suspended from?
The hyoid bone above → Attached to the trachea below.
258
What nerve provides both motor and sensory innervation to the larynx?
The vagus nerve [X].
259
What shape is the cricoid cartilage?
Like a signet ring → Broad lamina posteriorly, narrow arch anteriorly.
260
What articulates with the superolateral facet of the cricoid cartilage?
The base of the arytenoid cartilage.
261
What articulates with the lateral facet of the cricoid cartilage?
The inferior horn of the thyroid cartilage.
262
What attaches to the posterior surface of the cricoid lamina?
The esophagus (on midline ridge) and posterior cricoarytenoid muscles (on depressions).
263
What is the largest laryngeal cartilage?
The thyroid cartilage.
264
What forms the Adam’s apple (laryngeal prominence)?
The anterior fusion of the right and left thyroid laminae → Sharper angle in males (90°) vs. females (120°).
265
What connects the superior horn of the thyroid cartilage to the hyoid bone?
The lateral thyrohyoid ligament.
266
What landmark separates the laminae above the Adam’s apple?
The superior thyroid notch.
267
What is the oblique line on the thyroid cartilage for?
Muscle attachment: sternothyroid, thyrohyoid, and inferior constrictor muscles.
268
Where is the epiglottis attached?
By its stem to the thyroid cartilage via the thyroepiglottic ligament.
269
What structure lies behind the epiglottis?
The pharyngeal part of the tongue.
270
What is the epiglottic tubercle?
A raised area on the posterior surface of the epiglottis (inferior half).
271
What does the base of the arytenoid cartilage articulate with?
The cricoid cartilage (superolateral facet).
272
What is the apex of the arytenoid cartilage capped by?
The corniculate cartilage.
273
What attaches to the vocal process of the arytenoid cartilage?
The vocal ligament.
274
What attaches to the muscular process of the arytenoid cartilage?
The posterior and lateral cricoarytenoid muscles.
275
What muscles cover the posterior surface of the arytenoid cartilage?
The transverse arytenoid muscle.
276
Where are the corniculate cartilages located?
On the apex of each arytenoid cartilage → Project posteromedially.
277
Where are the cuneiform cartilages located?
Anterior to corniculate cartilages, suspended in the aryepiglottic fold of the fibro-elastic membrane.
278
What connects the arytenoids to the epiglottis?
A portion of the fibro-elastic membrane (aryepiglottic fold), containing cuneiform cartilages.
279
What connects the thyroid cartilage to the hyoid bone?
Thyrohyoid membrane → Thickened medially as the median thyrohyoid ligament and laterally as the lateral thyrohyoid ligaments.
280
What structures pass through the lateral aperture of the thyrohyoid membrane?
Superior laryngeal artery, internal branch of superior laryngeal nerve, and lymphatics.
281
What is the hyo-epiglottic ligament?
Connects the epiglottis (midline) to the body of the hyoid bone.
282
What is the cricotracheal ligament?
Connects the cricoid cartilage to the first tracheal ring.
283
What does the conus elasticus connect?
From cricoid arch to the vocal process of arytenoid and thyroid cartilage.
284
What does the free upper edge of the conus elasticus form?
The vocal ligament, under the vocal fold (true vocal cord).
285
What is the median cricothyroid ligament?
Midline thickening of the conus elasticus → Site for emergency airway access (cricothyrotomy).
286
What structures does the quadrangular membrane connect?
From epiglottis to arytenoid and corniculate cartilages.
287
What does the free lower edge of the quadrangular membrane form?
The vestibular ligament, under the vestibular fold (false vocal cord).
288
What movement occurs at the cricothyroid joint?
Thyroid cartilage tilts forward and down → Tenses and lengthens the vocal ligaments (raises pitch).
289
What movement occurs at the crico-arytenoid joint?
Arytenoid cartilages rotate and glide → Adducts/abducts the vocal folds (opens/closes rima glottidis).
290
What is the laryngeal inlet?
The superior opening of the larynx → Opens into pharynx just behind the tongue.
291
What forms the borders of the laryngeal inlet?
Anterior: Epiglottis
Lateral: Aryepiglottic folds (with corniculate and cuneiform cartilages)
Posterior: Interarytenoid notch (midline depression)
292
What is the inferior opening of the larynx?
A horizontal opening into the trachea, encircled by the cricoid cartilage → Always open.
293
What are the three major regions of the larynx?
Vestibule: From laryngeal inlet to vestibular folds
Middle chamber: Between vestibular and vocal folds
Infraglottic cavity: From vocal folds to trachea
294
What is a laryngeal ventricle?
Lateral mucosal recess between vestibular and vocal folds.
295
What is a laryngeal saccule?
Tubular extension of the ventricle → Contains mucous glands to lubricate the vocal folds.
296
What is the rima vestibuli?
Opening between vestibular folds (false cords).
297
What is the rima glottidis?
Opening between vocal folds (true cords) → Main airway passage regulated by arytenoid movement.
298
What movement closes or opens the rimae?
Arytenoid cartilage movement via intrinsic muscles of the larynx.
299
What is the action of the cricothyroid muscle?
Tilts the thyroid cartilage forward → Tenses and lengthens the vocal folds (raises pitch).
300
What nerve innervates the cricothyroid muscle?
External branch of the superior laryngeal nerve (branch of vagus nerve [X]) → Only intrinsic laryngeal muscle not innervated by recurrent laryngeal nerve.
301
What is the function of the posterior cricoarytenoid muscles?
Abduct and externally rotate arytenoid cartilages → Opens the rima glottidis → Only muscle that opens the airway.
302
What is the innervation of the posterior cricoarytenoid?
Recurrent laryngeal nerve [X]
303
What is the action of the lateral cricoarytenoid muscles?
Adduct (close) the vocal folds → Internally rotates arytenoids.
304
What is the innervation of the lateral cricoarytenoid?
Recurrent laryngeal nerve [X]
305
What is the action of the transverse arytenoid?
Adducts the arytenoid cartilages → Helps close the rima glottidis.
306
What is its innervation?
Recurrent laryngeal nerve [X]
307
What is the action of the oblique arytenoid muscles?
Narrows the laryngeal inlet by approximating arytenoids and pulling epiglottis toward them → Continue into aryepiglottic fold.
308
Innervation?
Recurrent laryngeal nerve [X]
309
Function of thyroarytenoid muscles?
Sphincter of vestibule; narrows laryngeal inlet by pulling arytenoids forward and epiglottis backward.
310
What fibers continue into the aryepiglottic fold?
Thyroepiglottic part of thyroarytenoid.
311
Innervation?
Recurrent laryngeal nerve [X]
312
What is the function of the vocalis muscles?
Fine control of vocal fold tension → Runs parallel to and inserts into vocal ligament.
313
Innervation?
Recurrent laryngeal nerve [X]
314
What happens to the larynx during quiet respiration?
Rima glottidis, vestibuli, and inlet are open → Arytenoids are abducted, rima glottidis is triangular.
315
What happens during forced inspiration?
Posterior cricoarytenoid abducts folds → Rima glottidis becomes rhomboid-shaped and airway widens.
316
How is sound produced in the larynx?
Adduction of vocal folds → Air is forced through closed rima glottidis, causing vibration.
317
Which muscles control vocal fold tension during speech?
Vocalis (fine control) and cricothyroid (gross tension increase).
318
What is effort closure and when does it happen?
Full closure of rima glottidis, vestibuli, and vestibule → Stabilizes thorax (e.g. during lifting, coughing, defecation).
319
What happens to the larynx during swallowing?
Rima glottidis, vestibuli, and inlet are closed
Larynx moves up and forward
Epiglottis folds down → Prevents aspiration
320
What facilitates esophageal opening during swallowing?
Upward and forward movement of the larynx, which pulls open the esophagus (attached to posterior cricoid lamina).
321
What are the two main arteries supplying the larynx?
Superior and inferior laryngeal arteries
322
What is the origin and path of the superior laryngeal artery?
From superior thyroid artery (branch of external carotid) → Passes through thyrohyoid membrane with internal laryngeal nerve.
323
What is the origin and path of the inferior laryngeal artery?
From inferior thyroid artery (branch of thyrocervical trunk, subclavian) → Ascends in tracheoesophageal groove with recurrent laryngeal nerve, enters larynx deep to inferior constrictor.
324
Where do the superior laryngeal veins drain?
Into superior thyroid veins → Then into internal jugular vein.
325
Where do the inferior laryngeal veins drain?
Into inferior thyroid veins → Then into left brachiocephalic vein.
326
Where do lymphatics from above the vocal folds drain?
Follow superior laryngeal artery → Drain into deep cervical nodes near common carotid bifurcation.
327
Where do lymphatics from below the vocal folds drain?
Into deep nodes around inferior thyroid artery, front of cricothyroid ligament, or upper trachea.
328
What are the branches of the superior laryngeal nerve?
External and internal branches.
329
What does the external branch of the superior laryngeal nerve supply?
Cricothyroid muscle (motor) and inferior constrictor.
330
What does the internal branch of the superior laryngeal nerve supply?
Sensory to larynx above the vocal folds → Passes through thyrohyoid membrane.
331
What is the motor function of the recurrent laryngeal nerve?
Innervates all intrinsic laryngeal muscles except cricothyroid.
332
What is the sensory function of the recurrent laryngeal nerve?
Larynx below the vocal folds.
333
Where does the left recurrent laryngeal nerve loop?
Under the aortic arch in the thorax.
334
Where does the right recurrent laryngeal nerve loop?
Around the right subclavian artery in the root of the neck.
335
Where do both recurrent laryngeal nerves ascend?
In the tracheoesophageal groove, entering the larynx deep to the inferior constrictor.
336
Where does the esophagus begin and end?
Begins at C6 (inferior cricoid cartilage) → Ends at T11 (cardiac opening of the stomach).
337
Through what structure does the esophagus enter the abdomen?
Esophageal hiatus in the diaphragm at T10.
338
Is the esophagus midline in the thorax?
Yes, it generally runs midline but deviates anterior and left near the diaphragm.
339
What lies anterior to the esophagus?
Right pulmonary artery, left main bronchus, and left atrium (separated by pericardium).
340
What lies posterior to the esophagus?
Thoracic duct, thoracic aorta, hemiazygos vein, and posterior intercostal vessels.
341
What lies laterally to the esophagus?
Right side: Parietal pleura, left side: Thoracic aorta (laterally/posteriorly).
342
What are the four natural constrictions of the esophagus?
Pharyngoesophageal junction (C6)
Aortic arch crossing
Left main bronchus crossing
Esophageal hiatus in diaphragm (T10)
343
Why are constrictions clinically important?
Foreign bodies, corrosives, and instruments are more likely to lodge or cause damage at these sites.
344
What arteries supply the thoracic esophagus?
Esophageal branches of thoracic aorta
Bronchial arteries
Ascending branches of left gastric artery (from abdomen)
345
How does venous drainage of the esophagus occur?
To azygos and hemiazygos veins
To left gastric vein → part of porto-systemic anastomosis
346
How is the upper (striated) esophagus innervated?
By branchial efferents from vagus nerves [X].
347
How is the lower (smooth muscle) esophagus innervated?
By parasympathetic (preganglionic) fibers of vagus nerves [X] → synapse in myenteric and submucosal plexuses.
348
What nerves carry physiological afferents (e.g. reflex) from the esophagus?
Vagal visceral afferents → Not involved in pain.
349
What nerves transmit pain signals from the esophagus?
Sympathetic trunks and splanchnic nerves.
350
Where do the vagus nerves form the esophageal plexus?
After passing posterior to the lungs, right and left vagus nerves branch and mix around the esophagus.
351
What trunks are formed just above the diaphragm from the esophageal plexus?
Anterior vagal trunk → mostly from left vagus
Posterior vagal trunk → mostly from right vagus
352
Which vagal trunks are associated with the abdominal esophagus?
Anterior vagal trunk → mostly from left vagus nerve
Posterior vagal trunk → mostly from right vagus nerve
352
Where does the abdominal esophagus begin and end?
From esophageal hiatus (T10) to cardial orifice of the stomach (just left of midline, near T11).
353
What arteries supply the abdominal esophagus?
Esophageal branches of the left gastric artery (from celiac trunk)
Esophageal branches of the left inferior phrenic artery (from abdominal aorta)
354
What are the four regions of the stomach?
Cardia (around esophageal opening)
Fundus (above the cardial orifice)
Body (largest part)
Pyloric part (includes antrum, canal, and ends at pylorus)
355
Where is the pyloric orifice located?
Just right of midline, at L1, in the transpyloric plane.
356
What is the pyloric sphincter?
A circular muscle ring controlling passage of food into the duodenum.
357
What is the greater curvature?
The lateral convex border of the stomach → Attachment for gastrosplenic ligament and greater omentum.
358
What are the main arteries supplying the lesser curvature?
Left gastric artery (from celiac trunk)
Right gastric artery (from hepatic artery proper)
358
What is the lesser curvature?
The medial concave border → Attachment for the lesser omentum.
359
What is the cardial notch?
The angle between the esophagus and fundus.
359
What is the angular incisure?
A notch on the lesser curvature separating the body and pyloric part.
360
What arteries supply the greater curvature?
Right gastro-omental artery (from gastroduodenal artery)
Left gastro-omental artery (from splenic artery)
361
What variant artery may supply the posterior stomach?
Posterior gastric artery (from splenic artery) → not always present
362
What are the three parts of the small intestine?
✅ Duodenum, jejunum, and ileum
363
❓ Where does the small intestine start and end?
✅ From the pyloric orifice to the ileocecal fold
364
❓ What is the total length of the small intestine?
✅ Approximately 6–7 meters
365
❓ What is the length and shape of the duodenum?
✅ 20–25 cm, C-shaped → wraps around the head of the pancreas
366
❓ Which part of the duodenum is intraperitoneal?
✅ The first part (superior portion) near the pylorus
367
❓ What are the four parts of the duodenum?
Superior (1st) – At L1, anterior to bile duct, portal vein, IVC
Descending (2nd) – Contains major & minor duodenal papillae
Inferior (3rd) – Crosses over IVC, aorta, vertebral column, crossed anteriorly by SMA/SMV
Ascending (4th) – Ascends to L2, ends at duodenojejunal flexure
368
What is the ligament of Treitz?
The suspensory muscle of the duodenum → supports the duodenojejunal flexure
369
What is the common site for duodenal ulcers?
The ampulla (cap) of the 1st part of the duodenum
370
Where does the foregut–midgut transition occur?
Just below the major duodenal papilla (2nd part of duodenum)
371
What arteries supply the duodenum?
Gastroduodenal artery branches
Anterior/posterior superior pancreaticoduodenal arteries
Anterior/posterior inferior pancreaticoduodenal arteries (from SMA)
First jejunal branch (from SMA)
Supraduodenal artery (from gastroduodenal)
372
How does the jejunum differ from the ileum?
Thicker wall, larger diameter
More plicae circulares (folds)
Longer vasa recta, fewer arcades
Less mesenteric fat
372
What portion of the small intestine does the jejunum represent?
The proximal two-fifths of the mobile small intestine
372
Where is the jejunum located?
Mostly in the left upper quadrant
373
What is the arterial supply of the jejunum?
Jejunal branches from the superior mesenteric artery (SMA)
374
What portion of the small intestine does the ileum represent?
The distal three-fifths
374
Where is the ileum located?
Mostly in the right lower quadrant
375
How is the ileum different from the jejunum?
Thinner wall, smaller diameter
Fewer folds, shorter vasa recta
More arcades, more mesenteric fat
376
What is the ileocecal fold, and what is its function?
Two mucosal flaps at the junction with cecum → act as a valve/sphincter → may prevent reflux and regulate flow to the colon
377
What arteries supply the ileum?
Ileal branches of SMA
Ileal branch of the ileocolic artery (from SMA)
378
What are the parts of the large intestine?
Cecum, appendix, colon (ascending, transverse, descending, sigmoid), rectum, and anal canal
379
What are the distinguishing features of the large intestine?
Taeniae coli (3 longitudinal muscle bands)
Haustra (sacculations)
Omental appendices (fat tags)
Larger diameter than small intestine
380
Where is the cecum located and is it retroperitoneal?
In the right iliac fossa, intraperitoneal (despite lacking a mesentery)
381
Where does the appendix attach?
To the posteromedial cecum, below the ileocecal junction
382
What structure suspends the appendix and carries its blood supply?
The mesoappendix
383
What is McBurney’s point?
Surface landmark for appendix: junction of lateral and middle third of a line from ASIS to umbilicus
384
What are the common positions of the appendix?
Retrocecal
Pelvic/descending
Subcecal
Pre-ileal
Postileal
385
What arteries supply the cecum and appendix?
Anterior & posterior cecal arteries (from ileocolic artery)
Appendicular artery (also from ileocolic artery)
All from superior mesenteric artery (SMA)
386
What is the peritoneal position of the ascending colon?
Secondarily retroperitoneal
387
Where does it turn into transverse colon?
At the right colic (hepatic) flexure, below the liver
388
Is the transverse colon intraperitoneal?
Yes → suspended by the transverse mesocolon
389
What is the left colic flexure?
Junction of transverse and descending colon, under the spleen, attached to diaphragm via phrenicocolic ligament
390
Is the descending colon retroperitoneal or intraperitoneal?
Secondarily retroperitoneal
391
Where does the sigmoid colon begin and end?
Begins at pelvic inlet, ends at S3 (where it becomes the rectum)
392
What suspends the sigmoid colon?
The sigmoid mesocolon
393
What arteries supply the ascending colon?
Colic branch of ileocolic artery
Right colic artery
Anterior/posterior cecal arteries
All from the SMA
394
What arteries supply the transverse colon?
Right colic artery (from SMA)
Middle colic artery (from SMA)
Left colic artery (from IMA)
395
What artery supplies the descending colon?
Left colic artery (from IMA)
396
What arteries supply the sigmoid colon?
Sigmoidal branches (from IMA)
396
What is the marginal artery of Drummond?
A continuous anastomosis along the inner border of the colon formed by branches of the SMA and IMA
397
Why is the marginal artery clinically important?
It provides collateral circulation to the colon → critical if one major artery is occluded
398
Where does the rectum begin and end?
Begins at S3 (rectosigmoid junction) → ends at the anal canal
399
Is the rectum intraperitoneal or retroperitoneal?
Retroperitoneal
400
What artery supplies the upper rectum?
Superior rectal artery (from inferior mesenteric artery)
400
What is the anal canal?
The terminal part of the large intestine, continuous inferiorly with the anus
401
What artery supplies the middle rectum?
Middle rectal artery (from internal iliac artery)
402
What artery supplies the anal canal and lower rectum?
Inferior rectal artery (from internal pudendal artery, which comes from internal iliac artery)
403
What is the largest visceral organ in the body?
The liver
404
In which abdominal regions is the liver located?
Right hypochondrium, epigastric, and partly left hypochondrium
405
What are the two surfaces of the liver?
Diaphragmatic surface → anterior, superior, posterior
Visceral surface → inferior
406
What peritoneal recesses are associated with the liver?
Subphrenic recess (separates liver from diaphragm)
Hepatorenal recess (between liver and right kidney/adrenal)
407
Name 5 structures related to the visceral surface of the liver.
Stomach, duodenum, gallbladder, right kidney, right colic flexure
407
What is the porta hepatis?
Hilum of the liver → entry for hepatic arteries and portal vein, exit for hepatic ducts
408
What is the falciform ligament?
Connects the liver to the anterior abdominal wall → divides subphrenic recess into right and left
409
What is the bare area of the liver?
Non-peritoneal area of liver directly against the diaphragm
410
What ligaments form the boundary of the bare area?
Anterior and posterior coronary ligaments, which meet at the triangular ligaments
411
What are the other key ligaments of the liver?
Hepatogastric ligament
Hepatoduodenal ligament
Coronary ligaments
Right/left triangular ligaments
412
Which lobes are functionally separate from the right lobe?
Caudate and quadrate lobes
413
What separates the right and left lobes of the liver?
Falciform ligament (anterior)
Ligamentum teres and ligamentum venosum (visceral)
414
What arteries supply the liver?
Right hepatic artery (from hepatic artery proper)
Left hepatic artery (from hepatic artery proper)
→ Both arise from the common hepatic artery (branch of celiac trunk)
414
What structures border the quadrate lobe?
Left: Ligamentum teres
Right: Fossa for gallbladder
415
What structures border the caudate lobe?
Left: Ligamentum venosum
Right: Groove for IVC
416
Where is the gallbladder located?
On the visceral surface of the right lobe of the liver, in a fossa between right and quadrate lobes
416
What are the parts of the gallbladder?
Fundus (may project below liver)
Body (contacts duodenum, transverse colon)
Neck (with spiral mucosal folds)
417
What artery supplies the gallbladder?
Cystic artery (branch of right hepatic artery)
418
What is the function of the gallbladder?
It stores and concentrates bile produced by the liver
419
What are the parts of the pancreas?
Head, uncinate process, neck, body, tail
420
Which part of the pancreas lies within the duodenal curve?
Head
420
What lies posterior to the neck of the pancreas?
The formation of the portal vein (from SMV + splenic vein)
420
What part of the pancreas passes in the splenorenal ligament?
Tail
421
Where does the main pancreatic duct (of Wirsung) open?
Into the major duodenal papilla (joined by the bile duct) → via ampulla of Vater
421
Which arteries supply the pancreas?
Gastroduodenal artery (from celiac trunk)
Anterior/posterior superior pancreaticoduodenal arteries (from gastroduodenal)
Anterior/posterior inferior pancreaticoduodenal arteries (from SMA)
Dorsal & great pancreatic arteries (from splenic artery)
422
What is the sphincter of Oddi?
Smooth muscle surrounding the ampulla of Vater, controls flow into duodenum
423
What is the accessory pancreatic duct (of Santorini)?
A secondary duct that opens into the minor duodenal papilla, superior to the major
424
What embryological origin explains the dual ducts of the pancreas?
Dorsal and ventral pancreatic buds from the foregut
425
What forms the common hepatic duct?
The union of right and left hepatic ducts
426
What joins the common hepatic duct to form the bile duct?
The cystic duct from the gallbladder
427
What lies posterior to the bile duct, hepatic artery, and portal vein?
The omental (epiploic) foramen
427
Where is the spleen located?
In the left upper quadrant, between ribs 9 and 10, against the diaphragm
428
What ligaments attach to the spleen?
Gastrosplenic ligament (to stomach)
Splenorenal ligament (to left kidney)
429
What do these ligaments contain?
Gastrosplenic → short gastric & left gastro-omental vessels
Splenorenal → splenic vessels (and tail of pancreas)
430
Where does the bile duct empty?
Into the major duodenal papilla (with the pancreatic duct)
430
What is the hilum of the spleen?
The entry point for splenic vessels and tail of pancreas (sometimes)
431
What artery supplies the spleen?
Splenic artery (from celiac trunk)
432
What are the three unpaired anterior branches of the abdominal aorta?
Celiac trunk, Superior mesenteric artery (SMA), Inferior mesenteric artery (IMA)
→ Supply foregut, midgut, hindgut, respectively
433
What vertebral level does the abdominal aorta begin?
T12 → through the aortic hiatus
434
At what vertebral level does the abdominal aorta bifurcate?
L4 → into the common iliac arteries
435
What structures are part of the foregut?
Abdominal esophagus, stomach, 1st part of duodenum (to major papilla), liver, gallbladder, pancreas, spleen
436
What are the 3 main branches of the celiac trunk?
Left gastric, Splenic, Common hepatic
437
What does the left gastric artery supply?
Lesser curvature of stomach and abdominal esophagus
→ Anastomoses with right gastric artery
438
What is the course of the splenic artery?
Tortuous path along superior border of pancreas, to splenorenal ligament, then spleen
439
What branches does the splenic artery give off?
Pancreatic branches (to neck, body, tail)
Short gastric arteries (to fundus)
Left gastro-omental artery (greater curvature)
440
What are the terminal branches of the gastroduodenal artery?
Right gastro-omental artery (greater curvature)
Anterior superior pancreaticoduodenal artery
440
What are the two terminal branches of the common hepatic artery?
Hepatic artery proper and gastroduodenal artery
441
What artery supplies the gallbladder?
Cystic artery, from right hepatic artery
442
What arteries supply the lesser curvature of the stomach?
Left gastric artery (from celiac trunk) and right gastric artery (usually from hepatic artery proper)
443
What is the origin of the superior mesenteric artery?
The anterior surface of the abdominal aorta just below the celiac trunk, at vertebral level LI.
→ It supplies midgut structures.
444
What does the superior mesenteric artery pass anterior to?
The left renal vein, uncinate process of the pancreas, and the inferior part of the duodenum.
→ It's crossed anteriorly by the splenic vein and neck of the pancreas.
445
What is the first branch of the superior mesenteric artery?
Inferior pancreaticoduodenal artery.
→ It supplies the head and uncinate process of the pancreas and the duodenum.
446
Into what branches does the inferior pancreaticoduodenal artery divide?
Anterior and posterior branches.
→ They anastomose with corresponding superior pancreaticoduodenal branches.
447
What are the branches from the left side of the superior mesenteric artery?
Jejunal and ileal arteries.
→ They form arcades and vasa recta to supply the small intestine.
448
How do jejunal and ileal vasa recta differ?
Jejunal vasa recta are long and closely spaced; ileal are short and widely spaced.
→ This also affects the appearance of mesenteric windows.
449
What are the three branches from the right side of the superior mesenteric artery?
Middle colic, right colic, and ileocolic arteries.
→ They supply terminal ileum, cecum, ascending colon, and proximal 2/3 of transverse colon.
450
Where does the middle colic artery go, and what are its branches?
It enters the transverse mesocolon and divides into right and left branches.
→ Right anastomoses with right colic; left with left colic (from IMA).
451
Is the right colic artery always present?
No, it is an inconsistent branch.
→ It supplies the ascending colon and anastomoses with middle colic and ileocolic arteries.
452
What branches does the ileocolic artery give off?
Colic, anterior and posterior cecal, appendicular, and ileal branches.
→ These supply ileum, cecum, appendix, and ascending colon.
453
What does the inferior mesenteric artery supply?
The hindgut: distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, and upper anal canal.
→ It arises at vertebral level LIII.
454
What are the branches of the inferior mesenteric artery?
Left colic, sigmoid arteries, and superior rectal artery.
→ These provide a descending vascular supply to the hindgut.
455
What does the left colic artery divide into?
Ascending and descending branches.
→ Ascending supplies distal transverse and upper descending colon; descending supplies lower descending colon.
456
What do the sigmoid arteries supply?
The lowest part of the descending colon and the sigmoid colon.
→ They anastomose with the left colic and superior rectal arteries.
457
What is the terminal branch of the inferior mesenteric artery?
The superior rectal artery.
→ It supplies the rectum and anastomoses with middle and inferior rectal arteries.
458
What structures drain into the portal vein?
Spleen, pancreas, gallbladder, and abdominal GI tract (except inferior rectum)
→ The portal vein delivers their blood to the liver for filtration.
459
After passing through hepatic sinusoids, where does blood go next?
Progressively larger veins → hepatic veins → inferior vena cava
→ This returns filtered blood to systemic circulation.
460
How is the portal vein formed?
By union of splenic and superior mesenteric veins
→ This occurs posterior to the neck of the pancreas at vertebral level L2.
461
What is the anatomical position of the portal vein in the lesser omentum?
Posterior to bile duct and hepatic artery proper, anterior to omental foramen
→ Lies in the right margin of the lesser omentum.
462
What are the main tributaries of the portal vein?
Right & left gastric veins, cystic veins, para-umbilical veins
→ These contribute venous drainage from stomach, gallbladder, and abdominal wall.
463
How is the splenic vein formed and where does it go?
Formed by small veins at spleen hilum → passes right, joins SMV posterior to pancreas neck
→ It lies along the body of the pancreas.
464
What are the tributaries of the splenic vein?
Short gastric veins, left gastro-omental vein, pancreatic veins, usually the inferior mesenteric vein
→ Drains fundus, stomach, pancreas, and parts of hindgut.
465
Where does the SMV join the splenic vein to form the portal vein?
Posterior to the neck of the pancreas
→ This is the formation site of the portal vein.
465
What does the superior mesenteric vein drain?
Small intestine, cecum, ascending colon, transverse colon
→ Begins in right iliac fossa, ascends in mesentery right of SMA.
466
Which veins are tributaries of the SMV?
Jejunal, ileal, ileocolic, right colic, middle colic veins; right gastro-omental vein; ant/post inf. pancreaticoduodenal veins
→ Veins mirror the arterial branches and drain midgut structures.
467
What does the inferior mesenteric vein drain?
Rectum, sigmoid colon, descending colon, splenic flexure
→ Begins as superior rectal vein and usually joins the splenic vein.
468
What are the tributaries of the inferior mesenteric vein?
Left colic vein, sigmoid veins, superior rectal vein
→ These veins accompany arteries of the same name.
469
Where does the IMV typically end?
Joins the splenic vein
→ But may also join at the junction of splenic and SMV, or directly into SMV.
470
How is lymph from abdominal GI tract and associated organs ultimately drained?
Via pre-aortic lymph nodes into the cisterna chyli
→ These nodes are grouped at origins of the celiac, SMA, and IMA.
471
Which structures drain to the celiac pre-aortic nodes?
Foregut structures (abdominal esophagus to major duodenal papilla)
→ Also receive lymph from SMA & IMA groups.
471
Which structures drain to the superior mesenteric pre-aortic nodes?
Midgut structures (duodenum below papilla to 2/3 transverse colon)
→ Drain upward to celiac nodes.
472
Which structures drain to the inferior mesenteric pre-aortic nodes?
Hindgut structures (last 1/3 transverse colon to upper rectum)
→ Drain upward to superior mesenteric nodes.
472
What are the two components of abdominal viscera innervation?
Extrinsic and intrinsic innervation → Extrinsic connects to the CNS; intrinsic refers to the enteric nervous system.
473
What does extrinsic innervation of abdominal viscera do?
Sends motor impulses from, and receives sensory information to, the CNS.
474
What is intrinsic innervation of the abdominal viscera?
The enteric nervous system → A self-regulating network of neurons controlling GI smooth muscle, secretion, and blood flow.
475
Which abdominal organs receive extrinsic innervation?
GI tract, spleen, pancreas, gallbladder, and liver.
476
Through what fibers do abdominal viscera communicate with the CNS?
Visceral afferent and visceral efferent fibers.
477
What are visceral efferent fibers part of?
The sympathetic and parasympathetic autonomic nervous system.
478
What are the two plexuses of the enteric nervous system?
Myenteric (Auerbach's) and submucosal (Meissner's) plexuses → Control GI muscle and secretion.
478
Which structures serve as conduits for extrinsic innervation?
Spinal roots, spinal nerves, anterior rami, rami communicantes, sympathetic trunks, splanchnic nerves, prevertebral plexus, vagus nerves.
479
Where are the sympathetic trunks located in the abdomen?
Anterolateral to the lumbar vertebral bodies.
480
Where do the sympathetic trunks terminate?
At the ganglion impar anterior to the coccyx.
481
How many lumbar sympathetic ganglia are there?
Four.
481
What types of fibers are in the sympathetic trunks?
Preganglionic and postganglionic sympathetic fibers, and visceral afferent fibers.
482
Which splanchnic nerves carry sympathetic fibers?
Thoracic, lumbar, and sacral splanchnic nerves.
483
Which splanchnic nerves carry parasympathetic fibers?
Pelvic splanchnic nerves.
484
What spinal segments give rise to pelvic splanchnic nerves?
S2–S4.
484
What does the greater thoracic splanchnic nerve supply?
Celiac ganglion → Originates from T5–T9(10) ganglia.
485
What does the lesser thoracic splanchnic nerve supply?
Aorticorenal ganglion → Originates from T9–T10(11).
486
What does the least thoracic splanchnic nerve supply?
Renal plexus → Arises from T12 ganglion.
487
Where do lumbar splanchnic nerves terminate?
Abdominal prevertebral plexus.
488
Where do pelvic splanchnic nerves terminate?
Inferior hypogastric plexus → Some fibers ascend to innervate the hindgut.
489
What are the three major divisions of the abdominal prevertebral plexus?
Celiac plexus, aortic plexus, superior hypogastric plexus.
490
Where do sacral splanchnic nerves terminate?
Inferior hypogastric plexus.
490
What ganglia are found in the celiac plexus?
Celiac ganglia, superior mesenteric ganglion, aorticorenal ganglia.
491
What ganglion is associated with the aortic plexus?
Inferior mesenteric ganglion.
491
Where does the superior hypogastric plexus continue?
Into the pelvis as the inferior hypogastric (pelvic) plexus via hypogastric nerves.
492
What are the two sources of parasympathetic innervation to abdominal viscera?
The vagus nerves (X) and the pelvic splanchnic nerves
493
Which parts of the GI tract are innervated by the vagus nerves?
Foregut and midgut → Parasympathetic fibers travel via anterior and posterior vagal trunks
494
What types of fibers do vagus nerve branches carry to the abdominal plexus?
Preganglionic parasympathetic fibers and visceral afferent fibers
494
How do vagus nerves reach the abdomen?
They enter with the esophagus through the diaphragm
495
What types of fibers does the abdominal prevertebral plexus receive?
Preganglionic parasympathetic (vagus and pelvic), sympathetic, and visceral afferent fibers.
496
Where are vagal fibers distributed after entering the abdomen?
Along the branches of the abdominal aorta via the abdominal prevertebral plexus
497
Which spinal cord levels give rise to pelvic splanchnic nerves?
S2 to S4
498
What do pelvic splanchnic nerves innervate in the abdomen?
The hindgut → Via the inferior mesenteric plexus and branches of the inferior mesenteric artery
499
Where do pelvic splanchnic nerves enter the autonomic plexus system?
Inferior hypogastric plexus
500
What is the enteric nervous system?
A local neuronal network in the GI wall regulating digestive function → Independent but modulated by autonomic input
501
What are the two main plexuses of the enteric nervous system?
Myenteric (Auerbach's) and submucosal (Meissner's) plexuses
502
What does the enteric system regulate?
GI secretion, blood flow, and peristalsis → Through motor and sensory neurons in the gut wall
503
Does the enteric system function independently of the CNS?
Yes, but it's modulated by postganglionic sympathetic and preganglionic parasympathetic fibers
504
Where do sympathetic fibers to the stomach originate?
Spinal cord level T6
504
How do preganglionic sympathetic fibers exit the spinal cord?
Through the anterior root → Then join the spinal nerve
505
Through which structure do these fibers leave the spinal nerve?
White ramus communicans
506
Where does the white ramus communicans lead the fiber?
To the sympathetic trunk
507
What happens to the fiber in the sympathetic trunk?
It passes through without synapsing → Enters the greater splanchnic nerve
508
Where does the greater splanchnic nerve carry the fiber?
Through the diaphragm to the celiac ganglion
508
Where does the preganglionic fiber synapse?
In the celiac ganglion → With a postganglionic neuron
509
Where does the postganglionic fiber travel next?
Along branches of the celiac trunk → Through the celiac plexus
510
Where does the postganglionic fiber end up?
In the stomach wall → Modulating enteric nervous activity
510
What are the nasal cavities?
The uppermost parts of the respiratory tract housing olfactory receptors → They are wedge-shaped, supported by bone and cartilage.
511
What are the anterior and posterior openings of the nasal cavities?
Anterior: nares; Posterior: choanae → Nares open onto the nose, choanae into the nasopharynx.
512
What separates the nasal cavities from each other and adjacent structures?
From each other: nasal septum;
From oral cavity: hard palate;
From cranial cavity: frontal, ethmoid, and sphenoid bones.
513
What are the three regions of each nasal cavity?
Nasal vestibule, respiratory region, olfactory region
514
What lines the nasal vestibule?
Skin with hair follicles
515
What lines the respiratory region and what is its function?
Ciliated respiratory epithelium → Filters, warms, and humidifies air.
516
Where is the olfactory region located and what does it contain?
At the apex of the nasal cavity → Contains olfactory epithelium with olfactory receptors.
517
What characterizes the lateral wall of the nasal cavity?
Three conchae (inferior, middle, superior) → Divide the cavity into air channels (meatuses).
518
What are the four air channels of the nasal cavity?
Inferior, middle, and superior meatuses; sphenoethmoidal recess
519
What is the function of the conchae?
Increase surface area → Enhance air conditioning and filtration.
520
Where does the nasolacrimal duct open?
Into the inferior nasal meatus → Drains tears into the nasal cavity.
520
Where do the paranasal sinuses open?
Into the lateral wall and roof of the nasal cavity
520
Why is the ethmoid bone important for the nasal cavities?
It contributes to the roof, lateral wall, and medial wall → Contains ethmoidal sinuses.
521
What connects the frontal sinus to the nasal cavity?
Frontonasal duct → Opens into the ethmoidal infundibulum.
522
Which bones form the skeletal framework of the nasal cavities?
Unpaired: ethmoid, sphenoid, frontal, vomer;
Paired: nasal, maxillary, palatine, lacrimal, inferior conchae
523
What is the cribriform plate and its function?
Perforated bone of ethmoid → Allows passage of olfactory nerve fibers to the cranial cavity.
523
What is the crista galli?
A vertical projection of the cribriform plate → Anchors the falx cerebri.
524
What is the perpendicular plate of the ethmoid bone?
A vertical sheet forming the upper part of the nasal septum
525
What are the superior and middle nasal conchae?
Curved processes of the ethmoid bone → Project into the nasal cavity.
526
What is the ethmoidal bulla?
A bulge formed by the middle ethmoidal cells on the lateral wall
527
What is the ethmoidal infundibulum?
A groove under the ethmoidal bulla → Leads to the frontal sinus via the frontonasal duct
528
What forms the external nose?
Bone and cartilage → Nasal bones, frontal process of maxilla, septal and alar cartilages
528
What forms the anterior part of the nasal septum?
Septal cartilage
529
Which cranial nerve carries smell from the nasal cavity?
Olfactory nerve (CN I)
530
Which nerve carries general sensation from the nasal cavity?
Trigeminal nerve (CN V) → V1 for anterior region, V2 for posterior region
531
Which nerve carries parasympathetic fibers to nasal glands?
Facial nerve (CN VII) → Via greater petrosal nerve and branches of V2
532
What are the main arteries supplying the nasal cavity?
Maxillary and facial arteries (from external carotid), and ethmoidal branches (from ophthalmic artery of internal carotid)
532
How do sympathetic fibers reach the nasal cavity?
From the T1 spinal level → Synapse in superior cervical ganglion → Travel along blood vessels or join V2 branches
533
How do paranasal sinuses develop?
As outgrowths from the nasal cavities that erode into surrounding bones.
533
What are the four paranasal sinuses?
Frontal, ethmoidal cells, sphenoidal, and maxillary sinuses → Named for the bones they occupy.
533
What are the common features of all paranasal sinuses?
They are lined by ciliated respiratory mucosa, open into the nasal cavity, and are innervated by branches of CN V.
534
Where are the frontal sinuses located?
In the frontal bone under the forehead, one on each side.
535
What is the shape and orientation of the frontal sinuses?
Triangular with a vertical base near midline and lateral apex.
535
How do frontal sinuses drain into the nasal cavity?
Via the frontonasal duct → Into the ethmoidal infundibulum of the middle meatus.
536
What nerve innervates the frontal sinuses?
Supraorbital nerve from the ophthalmic nerve (V1)
536
What is the arterial supply of the frontal sinuses?
Branches of the anterior ethmoidal arteries
537
Where are the ethmoidal cells located?
Within the ethmoidal labyrinth between the nasal cavity and the orbit.
538
What are the subdivisions of ethmoidal cells?
Anterior, middle, and posterior → Based on their drainage sites.
539
Where do anterior ethmoidal cells drain?
Into the ethmoidal infundibulum or frontonasal duct.
540
Where do middle ethmoidal cells drain?
Onto or just above the ethmoidal bulla.
541
Where do posterior ethmoidal cells drain?
Into the superior nasal meatus.
542
What nerves innervate the ethmoidal cells?
Anterior and posterior ethmoidal branches of nasociliary nerve (V1) and orbital branches of maxillary nerve (V2)
543
What arteries supply the ethmoidal cells?
Branches of the anterior and posterior ethmoidal arteries
544
What is the largest paranasal sinus?
Maxillary sinus → Located in the body of the maxilla
545
What is the shape of the maxillary sinus?
Pyramidal → Apex points laterally, base faces the nasal cavity.
546
Where does the maxillary sinus drain?
Into the middle meatus via the semilunar hiatus → Near the roof of the sinus.
547
What are the key anatomical relations of the maxillary sinus?
Superiorly: orbit; Inferiorly: roots of molar/premolar teeth; Posteriorly: infratemporal fossa
547
What nerves innervate the maxillary sinus?
Infraorbital and alveolar branches of maxillary nerve (V2)
548
Where do sphenoidal sinuses open?
Into the sphenoethmoidal recess on the posterior roof of the nasal cavity
549
What arteries supply the maxillary sinus?
Infraorbital and superior alveolar branches of maxillary artery
550
What are the anatomical relations of sphenoidal sinuses?
Above: pituitary gland and optic chiasm;
Lateral: cavernous sinus;
Below: nasal cavity
551
Why are sphenoidal sinuses clinically important?
They provide a surgical route to the pituitary gland through the nasal cavity.
552
What nerves innervate the sphenoidal sinuses?
Posterior ethmoidal nerve (V1) and orbital branches of maxillary nerve (V2)
553
What arteries supply the sphenoidal sinuses?
Pharyngeal branches of the maxillary artery
554
What forms the nasal septum?
Anterior: septal cartilage
Posterior: perpendicular plate of ethmoid and vomer
Additional: nasal crests, nasal spine of frontal bone, and rostrum of sphenoid
555
What forms the floor of the nasal cavity?
Hard palate → Palatine process of maxilla and horizontal plate of palatine bone
556
What is found near the front of the hard palate beneath the mucosa?
Superior aperture of the incisive canal → Lateral to the nasal septum
556
What forms the central roof of the nasal cavity?
Cribriform plate of the ethmoid bone
557
What forms the anterior part of the roof?
Nasal spine of frontal bone, nasal bones, septal and alar cartilages
557
What forms the posterior part of the roof?
Anterior surface of sphenoid, ala of vomer, sphenoidal process of palatine, vaginal process of medial pterygoid plate
558
What bones contribute to the bony lateral wall of the nasal cavity?
Ethmoid (labyrinth and conchae), perpendicular plate of palatine, medial pterygoid plate, lacrimal, maxilla, inferior concha
559
What cartilages support the lateral wall of the external nose?
Lateral process of septal cartilage, major and minor alar cartilages
560
What are the three conchae of the lateral wall?
Inferior, middle, and superior conchae → Create meatuses beneath each
561
What forms the ethmoidal bulla?
Middle ethmoidal cells bulging into the middle meatus
562
What is the semilunar hiatus and its relation to sinus drainage?
Curved groove under the bulla → Receives frontal and maxillary sinus drainage
563
Where does the nasolacrimal duct drain?
Inferior nasal meatus → Under the inferior concha
564
Where does the frontal sinus drain?
Middle meatus via frontonasal duct and ethmoidal infundibulum
565
Where do anterior ethmoidal cells drain?
Into the frontonasal duct or ethmoidal infundibulum
566
Where do middle ethmoidal cells drain?
Onto or just above the ethmoidal bulla
567
Where do posterior ethmoidal cells drain?
Superior nasal meatus
568
Where does the maxillary sinus drain?
Semilunar hiatus of middle meatus → Just below the ethmoidal bulla
569
Which sinus drains into the sphenoethmoidal recess (roof)?
Sphenoidal sinus → Only sinus that does not drain onto the lateral wall
570
What are the nares?
Oval anterior openings of the nasal cavities → Located on the inferior aspect of the external nose
571
What structures keep the nares open?
Alar and septal cartilages, inferior nasal spine, and adjacent margins of the maxillae
572
Which muscles widen the nares?
Nasalis, depressor septi nasi, and levator labii superioris alaeque nasi
573
What are the choanae?
Rigid, bony posterior openings between the nasal cavities and nasopharynx
574
What bones form the choanae?
Inferior: horizontal plate of palatine bone
Lateral: medial plate of pterygoid process
Medial: vomer
Roof: ala of vomer, vaginal process of medial pterygoid plate, body of sphenoid
575
What passes through the cribriform plate?
Olfactory nerve (CN I) fibers → Into the olfactory bulb
576
What else passes near the cribriform plate into the nasal cavity?
Anterior ethmoidal nerve (V1) and vessels
577
What does the foramen cecum connect in some individuals?
Nasal veins and the superior sagittal sinus → Acts as an emissary vein
578
What is the sphenopalatine foramen?
Communication between the nasal cavity and pterygopalatine fossa
579
What structures pass through the sphenopalatine foramen?
Sphenopalatine artery, nasopalatine nerve, superior nasal branches (V2)
580
What passes through the incisive canal?
Nasopalatine nerve (nasal to oral) and terminal part of greater palatine artery (oral to nasal)
581
Which nerves enter the nasal cavity through small foramina in the lateral wall?
Infraorbital branches (V2), alar branches of facial artery, inferior nasal branches from greater palatine nerve (V2)
582
Which arteries from the external carotid supply the nasal cavity?
Sphenopalatine, greater palatine, superior labial, and lateral nasal arteries
583
Which arteries from the internal carotid supply the nasal cavity?
Anterior and posterior ethmoidal arteries → From the ophthalmic artery
584
What is the largest artery of the nasal cavity?
Sphenopalatine artery → Terminal branch of maxillary artery
585
What areas does the sphenopalatine artery supply?
Lateral and medial walls → Via posterior lateral nasal and septal branches
586
How does the greater palatine artery reach the nasal cavity?
Via the incisive canal → Supplies anterior septum and floor
587
What is the blood supply to the anterior nasal septum?
Anastomoses of sphenopalatine, greater palatine, anterior ethmoidal, and superior labial arteries
588
What are the anterior ethmoidal artery’s branches?
Medial and lateral wall branches → Continues as external nasal artery
589
Where do veins from the nasal cavity drain?
Facial vein (anterior), pterygoid venous plexus (posterior), and superior ophthalmic vein (through ethmoidal veins)
590
What is the clinical significance of emissary veins in the nasal region?
They can transmit infections from the face to the cranial cavity
591
What nerve carries olfactory sensation?
Olfactory nerve (CN I) → Through cribriform plate to olfactory bulb
592
What nerves provide general sensation to the nasal cavity?
Ophthalmic nerve (V1) and maxillary nerve (V2)
593
Which V1 branches innervate the nasal cavity?
Anterior and posterior ethmoidal nerves → From nasociliary nerve
593
What does the anterior ethmoidal nerve supply?
Ethmoidal cells, frontal sinus, medial and lateral walls of nasal cavity, external nose (as external nasal nerve)
594
What does the posterior ethmoidal nerve supply?
Ethmoidal cells and sphenoidal sinus → Typically does not enter nasal cavity proper
595
Which V2 branches innervate the nasal cavity?
Posterior superior lateral and medial nasal nerves, posterior inferior nasal nerves, nasopalatine nerve, anterior superior alveolar nasal branch
596
What does the nasopalatine nerve innervate?
Nasal septum → Then passes to oral mucosa behind incisors via incisive canal
597
What provides parasympathetic innervation to nasal glands?
Facial nerve (VII) → Greater petrosal nerve → Pterygopalatine ganglion → Joins V2 branches
598
What provides sympathetic innervation to nasal mucosa?
T1 spinal level → Superior cervical ganglion → Deep petrosal nerve → Joins V2 branches
598
Where does lymph from anterior nasal cavity drain?
Forward to the face → Submandibular nodes
599
Where does lymph from posterior nasal cavity and sinuses drain?
Retropharyngeal nodes → Upper deep cervical lymph nodes
600
What are the lungs?
Organs of respiration located on either side of the mediastinum → Surrounded by pleural cavities
601
How does air enter and exit the lungs?
Via the main bronchi → Branches of the trachea
602
What is the role of pulmonary arteries and veins?
Pulmonary arteries: deliver deoxygenated blood from the right ventricle
Pulmonary veins: return oxygenated blood to the left atrium
602
Why is the right lung larger than the left?
Because the heart bulges more to the left
603
What are the parts of each lung?
Base, apex, costal and mediastinal surfaces, and three borders (anterior, posterior, inferior)
604
Where does the base of the lung sit?
On the diaphragm
604
What separates the lung surfaces and lobes?
Fissures (horizontal and oblique) and pleural invaginations
605
Where does the apex of the lung project?
Above the first rib into the root of the neck
606
What defines the costal and mediastinal surfaces?
Costal surface: adjacent to ribs
Mediastinal surface: faces mediastinum and vertebral column, contains hilum
607
Which lung border is smooth and rounded?
Posterior border
608
What is the lung root?
A collection of structures attaching the lung to the mediastinum → Covered by mediastinal pleura
608
What is the hilum?
The medial surface area where lung structures enter and exit → Outlined by pleural reflection
609
What is the pulmonary ligament?
A fold of pleura extending from the hilum to the mediastinum → Stabilizes the lung root during respiration
610
Which nerves pass relative to the lung roots?
Vagus nerve: posterior to root
Phrenic nerve: anterior to root
611
What structures are found in the lung root/hilum?
Pulmonary artery, two pulmonary veins, main bronchus, bronchial vessels, nerves, lymphatics
612
How many lobes and fissures does the right lung have?
3 lobes (superior, middle, inferior); 2 fissures (horizontal and oblique)
613
What does the horizontal fissure separate?
Superior lobe from the middle lobe
613
What does the oblique fissure separate?
Inferior lobe from both superior and middle lobes
614
Which mediastinal structures are related to the right lung?
Heart, SVC, IVC, azygos vein, esophagus
615
Which vessels arch over the superior lobe of the right lung?
Right subclavian artery and vein
616
How many lobes and fissures does the left lung have?
2 lobes (superior and inferior); 1 oblique fissure
617
What is the lingula of the left lung?
A tongue-like extension of the superior lobe → Overlaps the heart bulge
618
What structures are related to the left lung's medial surface?
Heart, aortic arch, thoracic aorta, esophagus
619
Which vessels arch over the superior lobe of the left lung?
Left subclavian artery and vein
620
Where does the trachea bifurcate?
At TIV/V level → Into right and left main bronchi
621
What is the carina?
A hook-shaped ridge at the tracheal bifurcation between the main bronchi
622
Why do inhaled objects more often lodge in the right lung?
Right main bronchus is wider and more vertical
623
What are the divisions of the bronchial tree?
Main bronchi → Lobar bronchi → Segmental bronchi → Bronchioles
624
What is a bronchopulmonary segment?
A lung region supplied by a segmental bronchus and pulmonary artery → Smallest resectable unit
625
How many bronchopulmonary segments are in each lung?
Ten → Some fuse on the left
626
Where do the pulmonary arteries originate?
From the pulmonary trunk → Carry deoxygenated blood to lungs
627
Describe the course of the right pulmonary artery.
Passes anterior to the right bronchus and tracheal bifurcation → Posterior to SVC and aorta
628
Describe the course of the left pulmonary artery.
Passes anterior to descending aorta and posterior to superior pulmonary vein
629
What do pulmonary veins do?
Return oxygenated blood from lungs to left atrium → Superior and inferior veins on each side
630
What do bronchial arteries supply?
Bronchial walls, visceral pleura, and pulmonary vessels → Nutritional supply
631
Where do bronchial arteries originate?
Right: from 3rd posterior intercostal artery (or left bronchial)
Left: 2 branches directly from thoracic aorta
631
Where do bronchial veins drain?
To pulmonary veins or left atrium, azygos (right), and superior intercostal or hemiazygos veins (left)
632
Which plexuses innervate the lungs?
Anterior and posterior pulmonary plexuses
633
What type of fibers do these plexuses carry?
Visceral afferent and efferent → From vagus nerve and sympathetic trunks
633
What is the autonomic effect of the vagus nerve on bronchioles?
Constriction
633
What is the autonomic effect of sympathetic innervation on bronchioles?
Dilation
634
What are the two lymphatic networks in the lungs?
Superficial (subpleural) and deep
635
Where do lung lymphatics drain?
Into tracheobronchial nodes → Then into bronchomediastinal trunks
636
Where do the bronchomediastinal trunks drain?
Into deep veins at the base of the neck, right lymphatic duct, or thoracic duct
636
What are the pleural cavities?
Spaces surrounding each lung → Located on either side of the mediastinum
637
How far do pleural cavities extend?
Superiorly: above rib I into the neck
Inferiorly: just above the costal margin
638
What forms the medial wall of each pleural cavity?
The mediastinum
639
What are the two types of pleura?
Parietal pleura and visceral pleura
640
What is the parietal pleura?
Pleura lining the walls of the pleural cavity
641
What is the visceral pleura?
Pleura covering the lung surface → Continuous with parietal pleura at the hilum
642
What lies between the visceral and parietal pleura?
A potential space with a thin layer of serous fluid
643
What are the subdivisions of parietal pleura based on location?
Costal, diaphragmatic, mediastinal, and cervical pleura
644
What is the cervical pleura (pleural cupola)?
Dome-shaped pleura lining the apex of the pleural cavity into the root of the neck
645
What supports the cervical pleura?
Suprapleural membrane → Attached to rib I and transverse process of CVII
646
Where are the parietal and visceral pleura continuous?
At the lung hilum → Surrounding the root of the lung
647
What nerves innervate the costal pleura?
Intercostal nerves → Pain referred to thoracic wall
647
What is the pulmonary ligament?
A fold of mediastinal pleura extending from the hilum to the mediastinum → Stabilizes the lung root
648
What nerves innervate the diaphragmatic and mediastinal pleura?
Phrenic nerves (C3–C5) → Pain referred to neck and shoulder
649
Is the visceral pleura sensitive to pain?
No → It has visceral afferents, but not pain fibers
650
How far above the first costal cartilage can the pleura project?
Up to 3–4 cm → But not above the neck of rib I
651
Where is the inferior boundary of the pleura in different planes?
Midclavicular line: rib VIII
Midaxillary line: rib X
Posterior: vertebra TXII
652
What marks the inferior limit of the lung itself?
Midclavicular: rib VI
Midaxillary: rib VIII
Posterior: vertebra TX
653
What are pleural recesses?
Spaces where parietal pleura folds onto itself → Not fully occupied by lung
654
What is the costomediastinal recess?
Where costal pleura meets mediastinal pleura → Largest on the left over the heart
654
What is the costodiaphragmatic recess?
Between costal and diaphragmatic pleura → Largest and clinically most important
655
When are the costodiaphragmatic recesses deepest?
After forced expiration → Shallowest after deep inspiration
656
Why are pleural recesses clinically significant?
They are sites where fluid can accumulate and be aspirated
657
Where are the sympathetic trunks located in the posterior abdominal region?
Anterolateral to lumbar vertebral bodies → Continue into pelvic cavity
658
What do the sympathetic paravertebral ganglia contain?
Postganglionic sympathetic neuronal cell bodies
659
What do lumbar splanchnic nerves carry?
Preganglionic sympathetic fibers + visceral afferent fibers → From sympathetic trunk to abdominal plexuses
660
How many sympathetic ganglia are typically found in the posterior abdomen?
Four
661
What is the abdominal prevertebral plexus?
Network of nerves around the abdominal aorta → Extends from aortic hiatus to aortic bifurcation
662
What are the three major subdivisions of the abdominal prevertebral plexus?
Celiac plexus, abdominal aortic plexus, superior hypogastric plexus
663
What fibers pass through the abdominal prevertebral plexus?
Thoracic/lumbar splanchnic (sympathetic), vagus (parasympathetic), pelvic splanchnic (parasympathetic)
664
What are the prevertebral ganglia and where are they found?
Celiac, superior mesenteric, aorticorenal, and inferior mesenteric ganglia → Along abdominal aorta branches
665
What spinal nerves form the lumbar plexus?
T12 (subcostal) + L1–L4 anterior rami
666
Where does the lumbar plexus form?
Within the substance of the psoas major muscle
667
What is the positional relationship of lumbar plexus branches to psoas major?
Anterior: genitofemoral
Medial: obturator
Lateral: iliohypogastric, ilio-inguinal, femoral, lateral cutaneous nerve of thigh
668
Where does the iliohypogastric nerve travel?
Across quadratus lumborum → Pierces transversus abdominis → Runs between transversus & internal oblique
669
What does the iliohypogastric nerve innervate?
Motor: abdominal muscles
Cutaneous: posterolateral gluteal skin (lateral branch), pubic region (anterior branch)
670
What is the course of the ilio-inguinal nerve?
Crosses quadratus lumborum and iliacus → Pierces transversus and internal oblique → Through inguinal canal
671
What does the ilio-inguinal nerve innervate?
Motor: abdominal muscles
Cutaneous: upper medial thigh, root of penis and scrotum (men) / mons pubis and labium majus (women)
672
Where does the genitofemoral nerve emerge?
From anterior surface of psoas major → Descends retroperitoneally posterior to ureter
673
What does the genital branch innervate?
Cremaster muscle (men) + skin of scrotum or labium majus
674
What does the femoral branch innervate?
Skin of upper anterior thigh
675
What is the course of the lateral cutaneous nerve of thigh?
From lateral border of psoas → Across iliacus → Posterior to inguinal ligament → Into thigh
676
What area does it supply?
Skin of anterior and lateral thigh to the level of the knee
677
What is the course of the obturator nerve?
Emerges medially from psoas → Along pelvic wall → Through obturator canal into thigh
678
What does the obturator nerve supply?
Muscles: obturator externus, pectineus, adductors, gracilis
Skin: medial thigh
Joints: hip and knee (via saphenous nerve association)
679
Where does the femoral nerve emerge?
From lower lateral border of psoas major → Between psoas and iliacus → Enters thigh beneath inguinal ligament
680
What muscles does the femoral nerve innervate?
Iliacus, pectineus, sartorius, rectus femoris, vastus medialis, intermedius, lateralis
681
What skin areas does the femoral nerve supply?
Anterior thigh (via medial and intermediate cutaneous nerves)
Medial leg (via saphenous nerve)
682
Where are the kidneys located?
Retroperitoneal in the posterior abdominal wall → Lateral to the vertebral column
683
Which vertebral levels do the kidneys span in the supine position?
From TXII to LIII → Right kidney lies lower than the left
684
Which kidney is longer and more slender?
The left kidney → Also lies closer to the midline
685
What covers the superior pole of the right kidney?
Right suprarenal gland
686
What lies against the upper anterior surface of the right kidney?
The liver → Separated by peritoneum
687
What structures relate to the inferior pole of the right kidney?
Laterally: right colic flexure
Medially: loops of small intestine (intraperitoneal)
688
Which digestive organ lies medially to the right kidney?
Descending (second) part of the duodenum → Retroperitoneal
689
What covers the superior medial pole of the left kidney?
Left suprarenal gland
690
What intraperitoneal organs cover the superior pole of the left kidney?
Stomach and spleen
691
What retroperitoneal organ lies in front of the mid-left kidney?
Pancreas
692
What are the inferior anterior relations of the left kidney?
Laterally: left colic flexure + beginning of descending colon
Medially: jejunum (intraperitoneal)
693
Which structures lie posterior to both kidneys (medial to lateral)?
Psoas major → quadratus lumborum → transversus abdominis
694
Which ribs are posterior to the kidneys?
Right kidney: rib XII
Left kidney: ribs XI and XII
695
What lies between the posterior kidneys and ribs?
Costodiaphragmatic recesses of pleural sacs
696
What nerves and vessels pass posterior to the kidneys?
Subcostal nerves and vessels, iliohypogastric nerve, ilio-inguinal nerve
697
What is the perinephric (perirenal) fat?
Fat surrounding the kidney and suprarenal gland → Enclosed by renal fascia
698
What is the renal fascia?
A membranous condensation of extraperitoneal fascia surrounding the perinephric fat
699
How is the suprarenal gland separated from the kidney?
By a thin septum within the renal fascia
700
What happens to the renal fascia laterally?
Anterior and posterior layers fuse → May blend with transversalis fascia
701
What happens to the renal fascia superiorly?
Fuses and blends with diaphragm fascia
702
What happens to the renal fascia medially?
Anterior layer blends with connective tissue around aorta and IVC
Posterior layer fuses with fascia of psoas major
703
What do the anterior and posterior renal fascia layers enclose inferiorly?
The ureters
704
What is paranephric (pararenal) fat?
Fat located posterior and posterolateral to the kidney → Outside the renal fascia
704
What covers the external surface of each kidney?
A fibrous capsule → Easily stripped except in disease
705
What is the hilum of the kidney?
A vertical slit on the medial border → Entry/exit for renal vessels, lymphatics, nerves, and renal pelvis
706
What is the renal sinus?
Internal space continuous with the hilum → Contains renal vessels, fat, lymphatics, calices, and renal pelvis
707
What are the two main internal regions of the kidney?
Renal cortex (outer) and renal medulla (inner)
708
What are renal pyramids and how are they arranged?
Triangular medullary structures → Base faces cortex, apex (papilla) points to renal sinus
709
What surrounds each renal papilla?
A minor calyx → Receives urine from papillary ducts
710
How do the calices and renal pelvis form?
Minor calices → form major calices → form renal pelvis → becomes ureter
711
Where do the renal arteries arise from?
Abdominal aorta → Just below the superior mesenteric artery (L1–L2)
712
Which renal artery is longer and why?
Right renal artery → Passes posterior to inferior vena cava
713
Where are renal veins located relative to arteries?
Anterior to the renal arteries
714
What is clinically significant about the left renal vein?
It crosses anterior to the aorta and posterior to the superior mesenteric artery → Can be compressed
714
What are accessory renal arteries?
Extra arteries from aorta → May enter kidney directly (extrahilar)
715
Where does lymph from the kidneys drain?
To lateral aortic (lumbar) lymph nodes at origin of the renal arteries
715
What is the ureter and where does it begin?
A muscular tube → Begins at ureteropelvic junction (from renal pelvis)
716
Describe the path of the ureter to the bladder
Retroperitoneal → Descends on psoas major → Crosses pelvic brim over iliac vessels → Enters bladder wall
717
Why are ureteric constrictions clinically relevant?
Common sites for kidney stone (calculus) impaction
718
Which arteries supply the ureters?
Upper: renal arteries
Middle: aorta, gonadal, common iliac arteries
Lower: internal iliac artery branches
719
What are the 3 physiological constrictions of the ureter?
Ureteropelvic junction
Crossing iliac vessels at pelvic brim
Entrance to the bladder wall
720
How is the ureteric arterial supply organized?
Vessels divide into ascending and descending branches → Form longitudinal anastomoses
721
Where does lymph from the ureter drain?
Upper: lateral aortic nodes
Middle: common iliac nodes
Lower: external + internal iliac nodes
722
What innervates the ureters?
Renal, aortic, superior/inferior hypogastric plexuses → Sympathetic + parasympathetic
723
Where is ureteric pain referred to?
T11–L2 dermatomes → Posterolateral abdominal wall, pubic region, scrotum/labia majora, upper thigh
724
Where are the suprarenal glands located?
Associated with the superior pole of each kidney
→ Right gland is pyramid-shaped; left is semilunar and larger
725
What structures lie anterior to the right suprarenal gland?
Right lobe of liver and inferior vena cava
726
What lies anterior to the left suprarenal gland?
Stomach, pancreas, and occasionally the spleen
727
What lies posterior to both suprarenal glands?
Diaphragm
728
What surrounds the suprarenal glands?
Perinephric fat and renal fascia
→ A thin septum separates each gland from its associated kidney
729
What are the three arterial sources supplying the suprarenal glands?
Superior, middle, and inferior suprarenal arteries
→ Superior from inferior phrenic arteries, middle from aorta, inferior from renal arteries
730
What innervates the suprarenal glands?
Preganglionic sympathetic fibers from T8–L1
→ They pass through the sympathetic trunk and prevertebral plexus without synapsing
730
What is the venous drainage of the suprarenal glands?
Single suprarenal vein from each gland
→ Right drains into IVC; left drains into left renal vein
731
Where does the abdominal aorta begin and end?
Begins at TXII and ends at LIV vertebra
→ Bifurcates into right and left common iliac arteries
732
What are the three unpaired visceral branches of the abdominal aorta?
Celiac trunk, superior mesenteric artery, and inferior mesenteric artery
733
What are the paired visceral branches of the abdominal aorta?
Middle suprarenal, renal, and testicular/ovarian arteries
734
What are the posterior branches of the abdominal aorta?
Inferior phrenic arteries, lumbar arteries, and median sacral artery
735
Where do the inferior phrenic arteries arise and what do they supply?
Below the aortic hiatus; supply diaphragm and suprarenal glands
736
How many pairs of lumbar arteries are there?
Usually four pairs
→ They supply the body wall and spinal cord
737
What is the course of the median sacral artery?
Arises above aortic bifurcation; descends over lumbar vertebrae and sacrum
738
Where does the inferior vena cava (IVC) begin and end?
Begins at LV level from union of common iliac veins; ends at TVIII piercing diaphragm
739
What are the tributaries of the IVC?
Common iliac veins, lumbar veins, right gonadal vein, renal veins, right suprarenal vein, inferior phrenic veins, hepatic vein
740
Which lumbar veins may drain into the ascending lumbar veins?
First and second lumbar veins
741
What do ascending lumbar veins connect?
Common iliac and lumbar veins with azygos and hemiazygos veins
742
What is the main lymphatic drainage pathway from below the diaphragm?
Thoracic duct
743
What are the two main groups of abdominal lymph nodes?
Pre-aortic nodes and lateral aortic (lumbar) nodes
744
What do lateral aortic (lumbar) nodes drain?
Body wall, kidneys, suprarenal glands, testes or ovaries
745
What do pre-aortic nodes drain?
GI tract, spleen, pancreas, gallbladder, and liver
746
What are the names of the pre-aortic nodes?
Celiac, superior mesenteric, and inferior mesenteric nodes
747
What do the lumbar and intestinal lymph trunks form?
Cisterna chyli
→ Located behind the right side of the abdominal aorta at LI–LII; it is the origin of the thoracic duct
747
What structures make up the pelvic part of the urinary system?
Terminal ureters, bladder, and proximal urethra
748
Where do the ureters enter the pelvic cavity?
Through the pelvic inlet, anterior to the bifurcation of the common iliac artery
749
What structures cross the ureters in the pelvis?
Ductus deferens in men; uterine artery in women
750
Where is the bladder located when empty?
Entirely in the pelvic cavity
751
Where does the bladder expand when full?
Superiorly into the abdominal cavity
752
What are the main surfaces and features of the empty bladder?
Apex, base, superior surface, two inferolateral surfaces
753
What structure extends from the apex of the bladder to the umbilicus?
Median umbilical ligament (remnant of the urachus)
754
What is the trigone of the bladder?
Smooth triangular area between ureteric and urethral openings on the bladder base
755
What supports the inferolateral surfaces of the bladder?
Levator ani and obturator internus muscles
755
What is the neck of the bladder?
The lowest and most fixed part of the bladder, surrounding the origin of the urethra
756
What ligaments support the bladder neck in women?
Pubovesical ligaments
757
What ligaments support the bladder neck in men?
Puboprostatic ligaments
758
Where is the bladder located at birth?
Mostly abdominal, with urethra beginning near the upper margin of the pubic symphysis
759
How long is the male urethra?
About 20 cm
760
How many bends are in the male urethra when the penis is flaccid?
Two bends: at the root of the penis and between the root and body
761
What happens to the urethral bend during erection?
The bend between root and body disappears
762
What are the four parts of the male urethra?
Preprostatic, prostatic, membranous, and spongy
763
What is the preprostatic urethra associated with?
Internal urethral sphincter (smooth muscle preventing semen backflow)
764
What structure surrounds the prostatic urethra?
Prostate gland
765
What are the prostatic sinuses?
Depressions on either side of the urethral crest where prostatic ducts empty
766
What is the seminal colliculus?
Enlargement on the urethral crest marking the opening of the ejaculatory ducts
767
What is the prostatic utricle?
Blind-ended pouch on the seminal colliculus (homologue of uterus)
768
What part of the urethra passes through the deep perineal pouch?
Membranous urethra
769
What muscle surrounds the membranous urethra?
External urethral sphincter (skeletal muscle)
770
What surrounds the spongy urethra?
Corpus spongiosum (erectile tissue of the penis)
771
Where do the bulbourethral glands open?
Into the bulb of the spongy urethra
772
What is the navicular fossa?
Enlarged end of the spongy urethra
773
What is the external urethral orifice?
Sagittal slit at the tip of the penis
774
What are the main components of the male reproductive system?
Testes, epididymis, ductus deferens, ejaculatory ducts, urethra, and penis
775
What are the accessory glands of the male reproductive system?
Prostate (single), seminal vesicles (pair), bulbo-urethral glands (pair)
776
Where do the testes originate embryologically?
High on the posterior abdominal wall
777
Where do the testes descend to before birth?
Through the inguinal canal into the scrotum
778
Where do the lymphatics of the testes drain?
Lateral aortic (lumbar) and preaortic nodes
779
What covers the sides and anterior aspect of the testis?
Tunica vaginalis (a remnant of peritoneum)
780
What is the tunica albuginea?
Thick connective tissue capsule surrounding the testis
781
Where are sperm produced in the testis?
Seminiferous tubules
782
What is the mediastinum testis?
Connective tissue wedge where seminiferous tubules drain into the rete testis
783
How many efferent ductules drain into the epididymis?
Approximately 12–20
784
What forms the head of the epididymis?
Efferent ductules coiled into a mass at the posterior superior pole
785
What is the body and tail of the epididymis formed by?
A single coiled duct descending posterolaterally along the testis
786
What are the functions of the epididymis?
Sperm maturation and storage
787
What is the function of the ductus deferens?
Transports sperm from epididymis to ejaculatory duct
788
What structure does the ductus deferens travel through?
Spermatic cord and inguinal canal
789
What arteries does the ductus deferens cross in the pelvis?
Crosses external iliac artery and vein
790
What structure does the ductus deferens cross near the bladder?
Ureter (posterior to the bladder)
791
What is the ampulla of the ductus deferens?
Expanded portion between the ureter and ejaculatory duct
792
What are seminal vesicles?
Blind-ended, coiled accessory glands developing from the ductus deferens
793
Where are seminal vesicles located?
Between the bladder and rectum, lateral to the ductus deferens
794
What forms the ejaculatory duct?
Duct of the seminal vesicle + ductus deferens
795
What do seminal vesicles contribute to?
Volume of semen (ejaculate)
796
Where is the prostate located?
Inferior to the bladder, anterior to the rectum
797
What shape is the prostate?
Inverted rounded cone (base superior, apex inferior)
798
What muscles cradle the prostate?
Levator ani muscles
799
How does the prostate develop?
From 30–40 glands that grow from the urethral epithelium
800
Where do the prostatic ducts open?
Into prostatic sinuses on the posterior urethral wall
801
What passes through the prostate?
Ejaculatory ducts (open into prostatic urethra)
802
here are the bulbo-urethral glands located?
In the deep perineal pouch, lateral to the membranous urethra
803
Where do the ducts of the bulbo-urethral glands open?
Into the bulb of the spongy urethra
804
What is the function of the bulbo-urethral glands?
Lubrication of the urethra and pre-ejaculatory secretion
805
Where do the ovaries originate embryologically?
High on the posterior abdominal wall
806
Where do ovaries descend to before birth?
Lateral wall of the pelvic cavity (not through the inguinal canal)
807
What is the function of the ovaries?
Site of oogenesis and ovulation → Mature eggs are released into the peritoneal cavity
808
What directs ovulated eggs into the uterine tubes?
Fimbriae and cilia on the uterine tube infundibulum
809
Where is the uterus located?
In the midline between the bladder and rectum
809
What are the main parts of the uterus?
Body, cervix → Body joins the uterine tubes, cervix joins the vagina
809
What is the superior rounded part of the uterus above the tubes?
The fundus
810
What suspends the ovary?
The mesovarium (a part of the broad ligament)
811
Where do uterine tubes open?
Into the peritoneal cavity adjacent to the ovary
811
What happens to the uterus during pregnancy?
It expands superiorly into the abdominal cavity
811
Where does the blastocyst implant?
In the body of the uterus
812
What are the four parts of the uterine tube (lateral to medial)?
Fimbriae, infundibulum, ampulla, isthmus
812
What are the openings of the cervical canal?
External os (into vagina), internal os (into uterine cavity)
812
What supports the uterine tubes?
The mesosalpinx (part of the broad ligament)
812
Where does fertilization normally occur?
In the ampulla of the uterine tube
812
What is the vaginal vault?
Enlarged internal end of the vaginal canal
812
What is the cervix?
The inferior cylindrical portion of the uterus
812
What is the fornix of the vagina?
The gutter around the cervix → Posterior, anterior, and lateral fornices
812
What is the normal position of the uterus relative to the cervix and vagina?
Anteflexed on the cervix and anteverted on the vagina
812
What is the vagina?
Distensible fibromuscular tube, copulatory organ in women
812
What lies posterior to the vagina?
Rectum
812
What is the introitus?
External vaginal opening in the vestibule
812
What lies anterior to the vagina?
Bladder and urethra → Urethra is embedded in the anterior vaginal wall
812
Where is semen deposited during intercourse?
Vaginal vault → Sperm travels through cervix, uterus, and tubes
812
What happens to the vaginal canal at rest?
It is normally collapsed → Anterior and posterior walls in contact
812
What does pelvic fascia surround and form?
It surrounds the pelvic walls and viscera, and forms sheaths for vessels and nerves.
→ It’s a continuation of the extraperitoneal connective tissue of the abdomen.
812
What does the rectovaginal septum separate in women?
The posterior surface of the vagina from the rectum.
813
Which fascial ligaments help stabilize the uterus?
Pubocervical, transverse cervical (cardinal), and uterosacral ligaments.
→ The transverse cervical ligaments are the most important.
813
What does the prostatic fascia contain in men?
The prostatic venous plexus.
→ It is continuous posteriorly with the rectovesical septum.
813
What is the vesico-uterine pouch?
A shallow peritoneal recess between the bladder and uterus.
813
What is the recto-uterine pouch (pouch of Douglas)?
A deep recess between the uterus and rectum.
→ It’s the most dependent part of the peritoneal cavity in women.
813
What is the broad ligament?
A peritoneal fold that supports the uterus, uterine tubes, and ovaries.
→ It includes the mesometrium, mesosalpinx, and mesovarium.
813
What does the suspensory ligament of the ovary contain?
Ovarian vessels, lymphatics, and nerves.
813
What embryological structure gives rise to the ligament of the ovary and round ligament of the uterus?
The gubernaculum.
813
What pouch lies between the bladder and rectum in men?
The rectovesical pouch.
813
What are the contributions to the sacral plexus?
Lumbosacral trunk (L4–L5) and anterior rami of S1–S4.
813
What does the sciatic nerve innervate?
Posterior thigh, leg, and foot muscles; skin of lateral leg and foot.
813
What are the components and function of the pudendal nerve?
S2–S4; innervates perineal muscles and external sphincters.
→ It passes through both sciatic foramina and follows the internal pudendal vessels.
813
What do the motor branches of the sacral plexus innervate?
Gluteal region, pelvic wall, and pelvic floor muscles.
→ Includes gluteal nerves and nerves to obturator internus, quadratus femoris, piriformis, and levator ani.
813
What do the sensory branches of the sacral plexus supply?
Skin of inferior gluteal region, posterior thigh, and upper leg.
→ Via perforating cutaneous nerve and posterior cutaneous nerve of the thigh.
813
What muscles are innervated by the superior gluteal nerve (L4–S1)?
Gluteus medius, gluteus minimus, tensor fasciae latae.
813
What muscle is innervated by the inferior gluteal nerve (L5–S2)?
Gluteus maximus.
813
Which nerve passes through both sciatic foramina to supply obturator internus?
Nerve to obturator internus (L5–S2).
813
Which nerve innervates quadratus femoris and inferior gemellus?
Nerve to quadratus femoris.
813
What nerve supplies skin over the inferior buttocks?
Perforating cutaneous nerve.
813
Which nerves do not leave the pelvis but go directly to pelvic muscles?
Nerve to piriformis and nerves to levator ani and coccygeus.
813
What forms the coccygeal plexus?
Anterior rami of S4, S5, and Co.
813
What do the anococcygeal nerves innervate?
Skin in the anal triangle of the perineum.
813
How do sympathetic trunks enter the pelvic cavity?
Over the sacral ala, medial to lumbosacral trunks and posterior to iliac vessels.
813
What is the ganglion impar?
Terminal fusion of both sympathetic trunks anterior to the coccyx.
814
What is the function of gray rami communicantes in the pelvis?
Carry postganglionic sympathetic fibers to anterior sacral rami.
815
What do sacral splanchnic nerves carry?
Preganglionic sympathetic fibers to pelvic prevertebral plexuses.
816
Where are hypogastric nerves located?
Medial to internal iliac vessels at the pelvic inlet.
817
What forms the inferior hypogastric plexuses?
Hypogastric nerves + pelvic splanchnic nerves (S2–S4).
818
What are the four main subsidiary plexuses of the pelvic plexus?
Rectal, uterovaginal, prostatic, and vesical plexuses.
819
What do sympathetic fibers in the pelvis do?
Constrict vessels, close internal sphincters, stimulate ejaculation.
819
What are cavernous nerves and what do they innervate?
Extensions of the prostatic plexus (men) → innervate erectile tissue of penis.
820
What do parasympathetic fibers (S2–S4) in the pelvis do?
Vasodilation, bladder contraction, erection, modulate distal colon motility.
821
What type of fibers carry visceral pain to the spinal cord?
Visceral afferent fibers.
→ Most follow sympathetic fibers to thoracic/lumbar levels; cervix/bladder may follow parasympathetics to sacral levels.
822
What is the main artery of the pelvis and perineum?
Internal iliac artery.
→ Arises from the common iliac artery at LV–SI level.
823
What are the two terminal branches of the internal iliac artery?
Anterior trunk and posterior trunk.
824
What are the branches of the posterior trunk of the internal iliac artery?
Iliolumbar, lateral sacral, and superior gluteal arteries.
825
What does the iliolumbar artery supply?
Posterior abdominal wall and iliac fossa.
→ Via lumbar and iliac branches; lumbar branch supplies cauda equina.
825
What do the lateral sacral arteries supply?
Sacrum, sacral canal structures, and skin/muscle posterior to sacrum.
826
What is the largest branch of the internal iliac artery?
Superior gluteal artery.
→ Exits above piriformis and supplies gluteal region and pelvic wall muscles.
827
What artery gives rise to the superior vesical artery?
Umbilical artery.
→ Becomes the medial umbilical ligament postnatally.
828
What does the superior vesical artery supply?
Superior bladder and distal ureter.
→ May also supply ductus deferens in men.
829
What does the inferior vesical artery supply?
Bladder, ureter, seminal vesicle, and prostate (men).
→ Vaginal artery is its female equivalent.
830
What does the vaginal artery supply?
Vagina, adjacent bladder, and rectum.
831
What artery supplies the rectum and anastomoses with superior and inferior rectal arteries?
Middle rectal artery.
832
What artery travels through the obturator canal to supply the medial thigh?
Obturator artery.
→ Travels with the obturator nerve and vein.
833
What is the main artery of the perineum?
Internal pudendal artery.
→ Exits pelvis via greater sciatic foramen, re-enters via lesser foramen.
834
What artery supplies the erectile tissues of the penis and clitoris?
Internal pudendal artery.
835
What artery exits below the piriformis to supply the gluteal region and hip joint?
Inferior gluteal artery.
836
What is the major blood supply to the uterus?
Uterine artery.
→ Crosses ureter at base of broad ligament and anastomoses with ovarian artery.
837
From where do the ovarian arteries originate?
Abdominal aorta.
→ They descend to the pelvis and travel in the suspensory ligament of the ovary.
838
What ligament do ovarian arteries travel through to reach the ovary?
Suspensory ligament of the ovary (infundibulopelvic ligament).
839
With which artery do the ovarian arteries anastomose?
Uterine artery.
840
Where does the median sacral artery originate?
Posterior surface of the abdominal aorta, just superior to the aortic bifurcation.
840
What happens to ovarian arteries during pregnancy?
They enlarge significantly to help supply the uterus.
841
What does the median sacral artery supply?
Sacrum, coccyx, and gives off the last pair of lumbar arteries.
842
What do pelvic veins generally follow?
The course of internal iliac artery branches, except for the umbilical and iliolumbar arteries.
843
Where do pelvic veins drain?
Into internal iliac veins, which join the common iliac veins.
844
What is the pelvic venous plexus?
A network of interconnected veins around pelvic viscera (e.g., bladder, rectum, prostate, uterus, vagina).
844
How does the pelvic venous plexus contribute to portal-caval anastomoses?
Via the rectal venous plexus, connecting superior rectal veins (portal) and middle/inferior rectal veins (caval).
845
What are internal hemorrhoids?
Varices of the internal rectal plexus, above the pectinate line.
845
What are external hemorrhoids?
Varices of the external rectal plexus, subcutaneous around the external anal sphincter.
845
Where does the deep dorsal vein of the penis/clitoris drain?
Directly into the pelvic cavity via a gap near the perineal membrane, joining the prostatic or vesical plexus.
846
Where do the ovarian veins drain?
Right ovarian vein → inferior vena cava
Left ovarian vein → left renal vein
847
Where does the median sacral vein drain?
Into the left common iliac vein or at the junction of the common iliac veins.
848
Where does lymph from most pelvic viscera first drain?
Internal and external iliac nodes.
849
Where do lymphatics from the ovaries and uterine tubes drain?
Directly into lateral aortic (lumbar) nodes, following ovarian arteries.
850
What is the final destination of pelvic lymph drainage?
Lateral aortic (lumbar) nodes → lumbar trunks → thoracic duct.
851
What else drains into internal iliac nodes besides viscera?
Gluteal region and deep perineum.
852
What is the perineum?
A diamond-shaped region inferior to the pelvic floor, between the thighs.
→ It lies between the pubic symphysis (front), coccyx (back), and ischial tuberosities (sides).
853
What structures form the ceiling of the perineum?
Levator ani and coccygeus muscles (pelvic diaphragm).
854
How is the perineum divided?
Urogenital triangle (anterior) and anal triangle (posterior).
855
What are the main neurovascular supplies to the perineum?
Pudendal nerve (S2–S4) and internal pudendal artery.
856
What does the urogenital triangle contain?
Openings of the urinary and reproductive systems and external genitalia.
857
What supports the external genitalia?
Perineal membrane and deep perineal pouch.
858
What passes through the urogenital hiatus?
Urethra (both sexes) and vagina (in women).
859
What lies between the perineal membrane and superficial fascia?
Superficial perineal pouch containing erectile tissues and associated muscles.
860
What does the anal triangle contain?
Anus, external anal sphincter, and ischio-anal fossae.
861
What is the function of the ischio-anal fossae?
Allow expansion of the anal canal during defecation.
862
What muscle blends with the deep part of the external anal sphincter?
Levator ani.
862
What innervates the external anal sphincter?
Inferior rectal nerves (from pudendal nerve) and S4 branches.
863
What is the perineal membrane?
A thick fibrous sheet forming the floor of the deep perineal pouch.
864
What is located superior to the perineal membrane?
Deep perineal pouch containing external urethral sphincter and neurovasculature.
865
What are the erectile bodies in both sexes?
Corpora cavernosa (paired, dorsal)
Bulbs of vestibule (F) or corpus spongiosum (M) (ventral)
866
What forms the body of the clitoris or penis?
Distal ends of the paired corpora cavernosa.
867
What is the male equivalent of the bulbs of vestibule and glans clitoris?
Corpus spongiosum and glans penis.
868
What erectile tissue encloses the urethra in men?
Corpus spongiosum.
869
What supports the body of the clitoris?
A suspensory ligament attaching to the pubic symphysis.
870
What structures make up the clitoris?
Two corpora cavernosa and the glans clitoris → Root = crura; body = unattached corpora cavernosa.
871
What structures make up the penis?
Two corpora cavernosa and one corpus spongiosum (which contains the urethra).
872
What is the root of the penis composed of?
Two crura (corpora cavernosa) + bulb (corpus spongiosum).
873
What is the glans penis?
The expanded distal part of the corpus spongiosum over the ends of the corpora cavernosa.
874
What ligaments support the penis?
Suspensory ligament of the penis (pubic symphysis) and fundiform ligament (linea alba).
875
What nerves cause erection of the penis and clitoris?
Parasympathetic fibers from S2–S4 (pelvic splanchnic nerves).
876
What do these parasympathetic fibers stimulate?
Relaxation of arteries in erectile tissues → blood fills → erection.
877
What arteries supply the penis and clitoris?
Branches of the internal pudendal artery.
878
What nerves carry sensory input from the penis and clitoris?
Pudendal nerves (S2–S4).
879
What are the greater vestibular glands and where are they located?
Female mucous glands in the superficial perineal pouch, posterior to the bulbs of the vestibule.
880
What is the male equivalent of the greater vestibular glands?
Bulbo-urethral glands (in the deep perineal pouch).
880
What do the greater vestibular glands do?
Produce lubrication during sexual arousal.
881
What muscles are found in the superficial perineal pouch?
Ischiocavernosus, bulbospongiosus, superficial transverse perineal muscles.
881
What does the ischiocavernosus muscle do?
Covers the crura and compresses them to force blood into the body of the penis/clitoris.
882
What is the bulbospongiosus muscle attached to in women?
Perineal body, vestibular bulb, perineal membrane, blends with ischiocavernosus.
883
What is the bulbospongiosus muscle attached to in men?
Raphe over bulb of penis, perineal body, covers corpus spongiosum.
884
What are the functions of bulbospongiosus in both sexes?
Compress erectile tissue and force blood into the glans.
885
What are additional functions of bulbospongiosus in men?
Empty urethra after urination
Cause pulsatile emission of semen during ejaculation
886
What is the function of the superficial transverse perineal muscles?
Stabilize the perineal body → Attach from ischial tuberosities/rami to perineal body.
887
What structures make up the vulva?
Clitoris, vestibular apparatus, labia minora & majora, mons pubis.
888
What forms the frenulum of the clitoris?
Medial folds of the labia minora.
889
What forms the prepuce of the clitoris?
Lateral folds of the labia minora.
890
What is the hymen?
A ring-like membrane partially covering the vaginal opening.
890
Where do para-urethral (Skene’s) glands open?
On each side of the urethral orifice.
891
Where do greater vestibular (Bartholin’s) glands open?
Posterolateral to the vaginal orifice.
891
What is the mons pubis?
Fatty elevation over the pubic symphysis formed by united labia majora.
892
What is the male equivalent of the labia majora?
The scrotum.
893
What is the midline raphe of the scrotum?
Remnant of fusion of labioscrotal swellings.
894
What forms the glans penis?
The expanded end of the corpus spongiosum.
895
What is the prepuce?
A fold of skin covering the glans; removed during circumcision.
896
What is Colles' fascia and where is it located?
Membranous layer of superficial fascia in the urogenital triangle.
896
What is the frenulum of the glans?
A fold of skin attaching the glans to proximal skin of the penis.
897
Where is Colles’ fascia attached?
Posteriorly to perineal membrane, laterally to ischiopubic rami.
898
Can fluid in the superficial perineal pouch spread into the thigh?
No, because Colles' fascia fuses with deep fascia at the thigh border.
899
What is the main somatic nerve of the perineum?
Pudendal nerve (S2–S4).
900
Through what path does the pudendal nerve enter the perineum?
Greater sciatic foramen → wraps around sacrospinous ligament → lesser sciatic foramen → pudendal canal.
901
What are the three terminal branches of the pudendal nerve?
Inferior rectal nerve
Perineal nerve
Dorsal nerve of the penis/clitoris
902
What does the inferior rectal nerve innervate?
External anal sphincter, levator ani, and anal skin.
903
What does the perineal nerve innervate?
Muscles in superficial and deep perineal pouches; skin (posterior labial/scrotal branches).
904
What is the sensory nerve for the glans penis/clitoris?
Dorsal nerve of the penis/clitoris.
905
What other somatic nerves contribute sensory fibers to the perineum?
Ilio-inguinal, genitofemoral, posterior femoral cutaneous, anococcygeal nerves.
906
What fibers stimulate erection and how do they reach the perineum?
Parasympathetic fibers (S2–S4 via pelvic splanchnic nerves) → through deep perineal pouch.
907
What type of autonomic fibers travel along the pudendal nerve to skin?
Postganglionic sympathetic fibers.
908
What is the main artery of the perineum?
Internal pudendal artery → Branch of anterior trunk of internal iliac artery.
909
Through which foramen does the internal pudendal artery enter the perineum?
Greater sciatic foramen → wraps around ischial spine → lesser sciatic foramen.
910
Which canal does the internal pudendal artery travel in?
Pudendal canal → On lateral wall of the ischio-anal fossa.
911
What are the main branches of the internal pudendal artery?
Inferior rectal artery, perineal artery, arteries to erectile tissues (e.g., deep, dorsal, urethral, bulb).
912
What supplies the corpus spongiosum and bulb of the penis?
Artery of the bulb of the penis.
913
What artery supplies the penile urethra and surrounding tissue?
Urethral artery.
913
What supplies the crus and corpus cavernosum?
Deep artery of the penis.
914
What supplies the glans and dorsal surface of the penis?
Dorsal artery of the penis.
915
What supplies the bulbs of the vestibule?
Artery of the bulb of the vestibule.
916
What supplies the crura and corpus cavernosum of the clitoris?
Deep artery of the clitoris.
917
What supplies the glans clitoris and surrounding tissue?
Dorsal artery of the clitoris.
917
What do the external pudendal arteries supply?
Skin of the penis and scrotum or clitoris and labia majora → From femoral artery.
918
What artery supplies the testes?
Testicular artery → From abdominal aorta.
919
What artery accompanies the spermatic cord or round ligament?
Cremasteric artery → From inferior epigastric artery.
920
What is the main venous drainage of the perineum?
Internal pudendal veins → Drain to internal iliac vein.
921
What vein drains the glans and corpora cavernosa?
Deep dorsal vein of the penis/clitoris → Joins prostatic or vesical venous plexus.
922
What veins drain skin of penis/clitoris and scrotum/labia?
Superficial dorsal and external pudendal veins → Drain to femoral vein.
923
Where do lymphatics from deep perineal structures drain?
Internal iliac nodes.
924
Where do superficial tissues of penis/clitoris and labia/scrotum drain?
Superficial inguinal nodes.
925
Where do glans penis, glans clitoris, labia minora, and lower vagina drain?
Deep inguinal and external iliac nodes.
926
Where do the testes drain lymph?
Lateral aortic (lumbar) and pre-aortic nodes → At vertebral levels LI–LII.
927
927
928
928
929
930
931
931
932
