Region 13 - Orbit, Nasal cavity and Oral Cavity Flashcards
(209 cards)
1
Q
What bone forms the superior border of the base (orbital margin) of the orbit?
A
Frontal bone
2
Q
What bone forms the inferior border of the base (orbital margin) of the orbit?
A
Maxilla
Zygomatic bone
3
Q
What bone forms the medial border of the base (orbital margin) of the orbit?
A
Ethmoid bone
Lacrimal bone
Maxilla
4
Q
What bone forms the lateral border of the base (orbital margin) of the orbit?
A
Zygomatic bone
Greater wing of sphenoid
5
Q
What bones form the superior wall of the orbit?
A
Frontal bone
Lesser wing of sphenoid (near apex)
6
Q
What bones form the inferior wall of the orbit?
A
Maxilla (mainly)
Zygomatic bone
Palatine bone:
- In wall of inferior orbital fissure
7
Q
What bones form the medial wall of the orbit?
A
Orbital plate of ethmoid bone Contributions from: - Maxilla - Lacrimal bone - Sphenoid
8
Q
What bones form the lateral wall of the orbit?
A
Frontal process of zygomatic bone
Greater wing of sphenoid
9
Q
What structure demarcates the border between the inferior and lateral walls of the orbit?
A
Inferior orbital fissure
10
Q
What is the strongest wall of the orbit and why?
A
Lateral wall
Most exposed to trauma
11
Q
Where is the apex of the orbit?
A
At the optic canal in the lesser wing of sphenoid:
- Medial to superior orbital fissure
12
Q
What are the contents of the orbit?
A
Eyeball Fat and connective tissues Extraocular muscles Nerves and blood vessels Most of the lacrimal apparatus
13
Q
What are the tarsal plates?
A
Dense bands of connective tissue strengthening the upper and lower eyelids
14
Q
Where do the fibres of the palpebral portion of orbicularis oculi lie in relation to the tarsal plates?
A
In the connective tissue superficial to the tarsi
15
Q
What do the tarsal glands in the tarsal plates secrete and what is its purpose?
A
Lipid secretion:
- Prevents eyelids sticking together when closes
- Forms a barrier that lacrimal fluid cannot cross
16
Q
How are the tarsal plates joined to the orbital margins?
A
Medial palpebral ligament
Lateral palpebral ligament
17
Q
What ligament is the origin of orbicularis oculi?
A
Medial palpebral ligament
18
Q
What does the orbital septum span between?
A
From tarsi to the orbital margins
19
Q
What is the orbital septum continuous with?
A
Periosteum
20
Q
What is the function of the orbital septum?
A
Keeps orbital fat pad contained
21
Q
What is the course of the medial check ligament?
A
From medial rectus
To lacrimal bone
22
Q
What is the course of the lateral check ligament?
A
From lateral rectus
To zygomatic bone
23
Q
What is the function of the check ligaments of the eye?
A
Limit abduction and adduction of eyeball by resisting pull of medial and lateral recti
24
Q
What is the name of the ‘sling’ formed by the check ligaments blending with the fascia of the inferior oblique and inferior rectus muscles?
A
Suspensory ligament of the eyeball
25
What is the function of the suspensory ligament of the eyeball?
Supports eyeball
26
How can the outer layer of the eyeball be described?
Fibrous
27
Describe the sclera.
```
Tough and opaque
Covers posterior 5/6 of eyeball
Provides attachment for:
- Intraocular muscles
- Extraocular muscles
```
28
Describe the cornea.
```
Transparent
Covers anterior 1/6 of eyeball
Completely avascular
Highly sensitive to touch:
- CN V1
```
29
How can the middle layer of the eyeball be described?
Vascular
30
Describe the choroid.
```
Largest part (lines most of sclera)
Dark and highly pigmented
Vascular bed lies externally in choroid
```
31
What is the ciliary body?
A ring-like thickening of the vascular middle layer of the eye
32
What does the ciliary body lie posterior to?
Corneoscleral juntion
33
What type of muscle is the ciliary body?
Smooth muscle
34
What does the ciliary body control the thickness of? How?
Contraction and relaxation of its smooth muscle controls thickness of the lens
35
Where are the ciliary processes? What do they do?
On internal surface of ciliary body
| Secrete aqueous humour
36
Where is the iris found?
On anterior surface of lens
37
What is the pupil?
A central aperture of the iris
38
What is the inner layer of the eyeball?
Retina:
| - A sensory neural layer
39
Why is the optic disc the 'blind spot'?
No photosensitive cells found here:
| - Sensory fibres of CN II and central artery of retina travel out of/into eye here
40
Where does the macula lutea lie?
Lateral to optic disc
41
What is the macula lutea?
An area with a high concentration of cone cells:
- High visual acuity
- AKA the fovea
42
What fluid fills the anterior segment of the eyeball?
Aqueous humour
43
What is the anterior segment of the eyeball divided into?
Anterior chamber:
- Between cornea and iris
Posterior chamber:
- Between iris and ciliary body
44
What is the route of flow of aqueous humour?
Produced in posterior chamber of anterior segment
Passes through pupil
Enters anterior chamber of anterior segment
Drains into scleral venous sinus at corneoscleral junction
45
Describe the vitreous humour
Embryological
Transparent
Jelly-like
46
What is the function of the vitreous humour?
Fills the posterior segment of the eyeball
| Supports retina
47
What is the function of the intraocular muscles?
Control size of pupil
48
How are the fibres of the dilator pupillae arranged?
Radially
49
What is the function of the dilator pupillae?
Increase diameter of pupil
50
What is the innervation of dilator pupillae?
SNS controlled:
| - Nerve fibres on ophthalmic branch of ICA
51
How are the fibres of the sphincter pupillae arranged?
Circularly
52
What is the function of the sphincter pupillae?
Decrease diameter of pupil
53
What is the innervation of sphincter pupillae?
PNS controlled:
| - Nerve fibres from CN III
54
How do PNS fibres reach the intraocular (sphincter pupillae) muscle?
ENter the ciliary ganglion and reach iris via the short ciliary nerves
55
How do SNS fibres reach the intraocular (dilator pupillae) muscle?
Travel with nasociliary branch of CN V1 and its long ciliary nerves
56
What is the ciliary muscle?
A ring of smooth muscle in the middle layer of the eyeball
57
How does the ciliary muscle behave in the absence of nervous stimulation? What does this cause?
Muscle is relaxed:
- Diameter of muscular ring increases
- Zonular fibres under tension
- Lens stretched and is thinner
- Refracts light for distant vision
58
How does the ciliary muscle behave in the presence of PNS stimulation? What does this cause?
Muscle contracts:
- Diameter of muscular ring decreases
- Zonular fibres relax
- Lens thickens as less stretched
- Refracts light for near vision
59
What is the process by which light is refracted for near vision?
Accommodation
60
What innervates the ciliary muscle?
PNS stimulation from CN III:
| - Via short ciliary nerves
61
What is the origin and insertion of levator palpebrae superioris?
From orbital roof
| To upper eyelid
62
What is the origin and insertion of the recti muscles?
```
From annular ring
To sclera (anterior to equator)
```
63
What is the origin and insertion of the superior oblique?
```
From lesser wing of sphenoid
To sclera (posterior to equator)
```
64
What is the origin and insertion of the inferior oblique?
```
From anterior floor of orbit
To sclera (posterior to equator)
```
65
Why can the eye muscles move eyes in more than one direction?
Due to difference between the optical axis and axis of orbit
66
What is the angle between the axis of each orbit?
45 degrees
67
What is the angle between the lateral walls of each orbit?
90 degrees
68
Why is the lateral side of the eyeball more exposed?
The medial wall extends further anteriorly than the lateral wall
69
What is the optical axis?
A line passing through the point in the lens at which no refraction will occur
70
What is the innervation to the extraocular muscles?
```
Oculomotor nerve:
- Levator palpebrae superioris
- Superior rectus
- Medial rectus
- Inferior rectus
- Inferior oblique
Trochlear nerve:
- Superior oblique
Abducent nerve:
- Lateral rectus
```
71
What are the functions of superior rectus?
Elevation
Adduction
Intorsion
72
What are the functions of inferior rectus?
Depression
Adduction
Extorsion
73
What is the function of medial rectus?
Adduction
74
What is the function of lateral rectus?
Abduction
75
What are the functions of superior oblique?
Depression
Abduction
Intorsion
76
What are the functions of inferior oblique?
Elevation
Abduction
Extorsion
77
Where does CN VI run in the cavernous dural venous sinus?
Through the middle
| Close to ICA
78
Where do CNs III, IV, V1 and V2 run in the cavernous dural venous sinus (from superior to inferior)?
In lateral wall of cavernous dural venous sinus
79
Where does the frontal branch of CN V1 lie?
Superior to eyeball
80
What are the two branches of the frontal branch of CN V1 and where do they leave to enter onto the forehead?
Supraorbital nerve:
- Leaves via supraorbital notch
Supratrochlear nerve:
- Leaves medial to supraorbital nerve
81
What are the functions of the lacrimal branch of CN V1?
Sensory to lacrimal gland
| Carries PNS secretomotor fibres from pterygopalatine ganglion (greater petrosal nerve of CN VII)
82
What does the nasociliary branch of CN V1 give sensory fibres to?
Ciliary ganglion
83
What are the branches of the nasociliary nerve?
Anterior and posterior ethmoidal branches
84
What does the superior division of CN III do?
Motor supply to:
- Levator palpebrae superioris
- Superior rectus
85
What does the inferior division of CN III do?
```
PNS to ciliary ganglion and via short ciliary nerves to:
- Ciliary muscle
- Sphincter pupillae
Motor supply to:
- Medial rectus
- Inferior rectus
- Inferior oblique
```
86
How does the central artery of the retina reach the eye?
Arises inferior to CN II then pierces its sheath and runs within CN II to the eyeball
87
What artery does the central artery of the retina arise from?
Ophthalmic artery
88
What do the short posterior ciliary arteries supply?
Choroid
89
What do the long posterior ciliary arteries supply?
Ciliary plexus:
- Ciliary muscle
- Iris
90
How many short posterior ciliary arteries are there per eye?
6
91
How many long posterior ciliary arteries are there per eye?
2
92
What is the course of the long posterior ciliary arteries?
Pass between sclera and choroid
Anastomose with anterior ciliary arteries:
- From lacrimal artery
93
What are the other branches of the ophthalmic artery>
Supraorbital and supratrochlear arteries
| Anterior and posterior ethmoidal arteries
94
What veins drain to the superior ophthalmic vein?
Supraorbital vein
| Vorticose veins
95
What does the superior ophthalmic vein drain to?
Cavernous sinus
96
What do the vorticose veins drain to mainly?
Inferior ophthalmic vein:
| - Drains to pterygoid venous plexus
97
Where does the facial vein drain?
Inferior ophthalmic vein
98
Where does the lacrimal gland lie?
In fossa for lacrimal gland:
- Superolaterally in orbit
- In frontal bone
99
What are the parts of the lacrimal gland?
Orbital (superior)
| Palpebral (inferior)
100
What is the route of flow of lacrimal fluid from the lacrimal gland?
1. Fluid secreted into lateral part of superior conjunctival fornix
2. Fluid flows inferiorly
3. Fluid accumulates in lacrimal lake
4. Drains through lacrimal puncta and lacrimal canaliculi
5. Drains into lacrimal sac
6. Fluid drains into inferior nasal meatus via nasolacrimal duct
101
How do PNS fibres reach the lacrimal gland?
PNS fibres run in CN VII:
- PNS fibres in greater petrosal nerve (presynaptic)
- Joins deep petrosal nerve (SNS) from ICA plexus
- PNS (and SNS) fibres in nerve of pterygoid canal
- To pterygopalatine ganglion
- Zygomatic nerve (CN V2) brings fibres to lacrimal nerve (CN V1)
102
What is the arterial supply to the nasal cavity?
```
From ophthalmic artery:
- Anterior ethmoidal artery
- Posterior ethmoidal artery
From maxillary artery:
- Sphenopalatine artery
- Greater palatine artery
From facial artery:
- Septal branch of superior labial artery
- Lateral nasal arteries
```
103
What is the nerve supply to the external nose?
CN V1:
- Infratrochlear nerve = Skin lateral to root of nose
- External nasal branch of anterior ethmoidal nerve = Dorsum of nose
CN V2:
- Nasal branches of infraorbital nerve (alae)
104
What is the nerve supply to the medial wall of the internal nose (nasal septum)?
Anterosuperiorly is CN V1:
- Anterior ethmoidal nerve
Posteroinferiorly is CN V2:
- Nasopalatine nerve
105
What is the nerve supply to the lateral wall of the internal nose?
Anterosuperiorly is CN V1:
- Anterior ethmoidal nerve
Posteroinferiorly is CN V2:
- Branches of pterygopalatine ganglion
106
What bones contribute to the bony part of the nasal septum?
```
Perpendicular plate of ethmoid bone (superiorly)
Vomer bone (inferiorly)
Small contributions from:
- Palatine bone
- Maxilla
```
107
What bones contribute to the roof of the nasal cavity?
Nasal bone (and frontal)
Ethmoid bone
Sphenoid bone
108
What bones contribute to the floor of the nasal cavity?
Palatine process of maxilla (anteriorly)
| Horizontal plates of palatine bones (posteriorly)
109
What bones contribute to the lateral wall of the nasal cavity?
```
Ethmoid bone:
- Superior concha
- Middle concha
Inferior concha bone
Frontal process of maxilla
Palatine bone
Medial pterygoid plate of sphenoid
```
110
What is the vestibule of the nasal cavity?
Entrance
111
What are the choanae?
Opening of posterior nasal cavities into nasopharynx
112
What lies beneath each concha of the nasal cavities?
A meatus
113
What are the functions of the nasal conchae?
Warm air
Filter air
Turbulence
114
How does the frontal sinus drain into the nasal cavity?
Opens into middle meatus via:
- Ethmoidal infundibulum
- Semilunar hiatus
115
How do the anterior and middle ethmoidal sinuses drain into the nasal cavity?
Opens into middle meatus via:
- Ethmoidal infundibulum
- Can drain directly
116
How does the maxillary sinus drain into the nasal cavity?
Opens into middle meatus via:
- Maxillary ostium
- Semilunar hiatus
117
How does the posterior ethmoidal sinus drain into the nasal cavity?
Opens into superior meatus directly
118
How does the sphenoidal sinus drain into the nasal cavity?
Opens into sphenoethmoidal recess directly
119
What is the nerve supply to the frontal sinus?
Supraorbital nerve (CN V1)
120
What is the nerve supply to the anterior and middle ethmoidal sinuses?
Nasociliary nerve (CN V1)
121
What is the nerve supply to the maxillary sinus?
Superior alveolar nerve (CN V2)
122
What is the nerve supply to the posterior ethmoidal sinus?
Nasociliary nerve (CN V1)
123
What is the nerve supply to the sphenoidal sinus?
Posterior ethmoidal nerve (CN V1)
124
What do the posterior ethmoidal air cells form?
Bulge of the ethmoidal bulla
125
In an anterior view of a coronal section through the jaw, what is the order of muscles from most superficial (inferior) to the tongue?
```
Platysma
Anterior bellies of digastric
Mylohyoid
Geniohyoid
Tongue (genioglossus)
```
126
What is the course of mylohyoid?
Mandible to body of hyoid
127
What is the innervation to mylohyoid?
CN V3 (branch of inferior alveolar nerve)
128
What are the functions of mylohyoid?
Elevates hyoid and floor of mouth
| Depresses mandible
129
What is the course of the anterior belly of digastric?
Mandible to the body and greater horn of hyoid
130
What is the innervation to anterior belly of digastric?
CN V3
131
What are the functions of the anterior belly of digastric?
Elevates hyoid
| Depresses mandible
132
What is the course of the posterior belly of digastric?
Temporal bone to the body and greater horn of hyoid
133
What is the innervation to the posterior belly of digastric?
CN VII
134
What is the course of stylohyoid?
Styloid process (of temporal bone) to body of hyoid
135
What is the innervation to stylohyoid?
CN VII
136
What is the function of stylohyoid?
Elevates hyoid
137
What is the course of geniohyoid?
Mandible to body of hyoid
138
What is the innervation to geniohyoid?
C1 via CN XII
139
What is the function of geniohyoid?
Elevates hyoid
140
What is the location of the submandibular glands?
Along body of mandible:
- Partly superior and partly inferior to posterior half
Partly superficial and partly deep to mylohyoid
141
How long is the submandibular duct?
~5cm
142
Where does the submandibular duct arise?
From part of gland between mylohyoid and hyoglossus muscles
143
What nerve loops under the submandibular duct anteriorly?
Lingual nerve
144
Where does the submandibular duct open?
On a sublingual papilla beside the base of the lingual frenulum
145
What is the nerve supply to the submandibular gland?
PNS fibres from chorda tympani (CN VII) running in the lingual nerve (CN V3)
146
Where do the sublingual glands lie?
In floor of mouth between mandible and genioglossus
147
Where do the sublingual ducts open?
Floor of mouth along sublingual folds
148
What is the nerve supply to the sublingual glands?
PNS fibres from chorda tympani (CN VII) running in the lingual nerve (CN V3)
149
Where is the anterior part of the tongue (the body) found?
Oral cavity
150
What divides the anterior part of the tongue in half?
Midline groove
151
What are the lingual papillae on the anterior part of the tongue?
Fungiform
Filiform
Vallate
Foliate
152
What are the most numerous lingual papillae on the tip of the tongue?
Fungiform
153
What lingual papillae lie laterally?
Foliate
154
Which lingual papillae have no taste receptors?
Filiform
155
What is the innervation to the anterior tongue?
CN V3 - General sensory
| CN VII - Taste
156
Where is the root of the tongue?
In oropharynx
157
What divides the anterior and posterior parts of the tongue? Where is this found?
Terminal sulcus:
| - Lies immediately posterior to the v-shaped row of vallate papillae
158
What lingual papillae are found on the posterior part of the tongue?
None
159
What structure do the underlying lymphoid nodules form in the posterior tongue?
Lingual tonsil
160
What is the innervation to the posterior tongue?
CN IX:
- General sensory
- Taste
Small patch via internal laryngeal nerve (CN X)
161
What is the apex of the division between the anterior and posterior parts of the tongue called?
Foramen cecum:
| - Remnant of median thyroid diverticulum
162
What are the intrinsic tongue muscles?
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
163
Describe the intrinsic tongue muscles?
Change shape of tongue
Fibres in different orientations
All within tongue
All innervated by CN XII
164
What are the functions of genioglossus?
Depresses tongue
| Protrudes tip
165
What is the function of palatoglossus?
Elevates tongue
166
What are the functions of styloglossus?
Elevates and retracts tongue
167
What is the function of hyoglossus?
Depresses tongue
168
Where do the extrinsic muscles of the tongue originate and insert?
Originate outside tongue
| Insert into tongue
169
What is the innervation to the extrinsic muscles of the tongue?
```
CN XII:
- Genioglossus
- Styloglossus
- Hyoglossus
CN X in pharyngeal plexus:
- Palatoglossus
```
170
What are the branches of the lingual artery that supply the tongue?
```
Dorsal lingual arteries:
- Supplies root of tongue (posterior 1/3)
Deep lingual arteries:
- Supply body of tongue (anterior 2/3)
Sublingual arteries:
- Supply sublingual glands
```
171
What is the venous drainage of the tongue?
```
Dorsal lingual veins drain root:
- Accompany lingual artery
Deep lingual veins start at tip of tongue
Meet and form lingual vein:
- Drains to IJV
```
172
What is the lymphatic drainage of the tip of the tongue?
Submental nodes:
| - Very middle tip drains bilaterally
173
What is the lymphatic drainage of the lateral parts of the anterior 2/3 of the tongue?
Submandibular nodes (ipsilaterally)
174
What is the lymphatic drainage of the middle part of anterior 2/3 of the tongue?
Inferior deep cervical nodes (bilaterally)
175
What is the lymphatic drainage of the posterior 1/3 of the tongue?
Superior deep cervical nodes (bilaterally)
176
Where does lymph from the tip and the lateral parts of the anterior 2/3 of the tongue eventually drain to?
Deep cervical nodes
177
What bones form the hard palate?
Maxillae:
- Palatine processes
Palatine bones:
- Horizontal plates
178
What is the incisive fossa of the hard palate?
Midline depression
| Posterior to central incisors
179
What is the palatine raphe of the hard palate?
Midline structure marking site of palatal process fusion
180
What folds radiate laterally from the incisive fossa?
Transverse palatine folds
181
Where do the palatine glands lie and what do they secrete?
Deep to mucosa
| Secrete mucus
182
What is the greater palatine foramen of the hard palate?
A passage for the greater palatine vessels and nerves into the palate:
- Lies medial to 3rd upper molar
183
What is the lesser palatine foramen of the hard palate?
A passage transmitting the lesser palatine vessels and nerves to soft palate
184
What is the innervation to the hard palate?
Greater palatine nerves:
- Branch of pterygopalatine ganglion
- Sensory via CN V2
185
What is the arterial supply to the hard palate?
Greater palatine arteries:
| - Branch of descending palatine artery from maxillary artery
186
What is the venous drainage of the hard palate?
Drains to pterygoid venous plexus
187
What strengthens the soft palate anteriorly and what does it attach to?
Palatine aponeurosis:
| - Attaches to posterior edge of hard palate
188
What is the curved free margin of the soft palate?
Uvula
189
Where is the soft palate continuous with the walls of the pharynx and how are they joined?
Laterally
| Joined by palatopharyngeal arch
190
How is the soft palate connected to the tongue?
Palatoglossal arch
191
What do the tensor veli palatini and levator veli palatini both attach to?
Palatine aponeurosis
| Cartilage of pharyngotympanic tube
192
What does tensor veli palatine loop around?
Pterygoid hamulus of medial pterygoid plate of sphenoid
193
What is the innervation to tensor veli palatini?
CN V3
194
What are the remaining muscles of the soft palate that are innervated by CN X in pharyngeal plexus?
Levator veli palatini
Palatoglossus
Palatopharyngeus
Musculus uvulae
195
What is the sensory innervation to the soft palate?
```
Lesser palatine nerves:
- From pterygopalatine ganglion
- CN V2
Uvula supplied by CN IX:
- Sensory limb of gag reflex
```
196
What is the arterial supply to the soft palate?
Lesser palatine arteries:
| - Branch of descending palatine artery from maxillary artery
197
What is the venous drainage of the soft palate?
Drains to pterygoid venous plexus
198
What bone lies between the roots of different teeth?
Interalveolar septa (alveolar bone)
199
What bone lies between the roots of the same tooth (eg. a molar)?
Interradicular septum (alveolar bone)
200
What are the layers of a tooth from external to internal?
Enamel
Dentine
Pulp
201
What are the pointed eminences on teeth?
Buccal cusps
202
How many permanent teeth are there in adults?
32
203
What nerve supplies the maxillary incisors and canines?
Anterior superior alveolar nerve (CN V2)
204
What nerve supplies the maxillary premolars and 1/2 of first molar?
Middle superior alveolar nerve (CN V2)
205
What nerve supplies the other 1/2 of the first molar and the 2nd and 3rd molars?
Posterior superior alveolar nerve (CN V2)
206
What nerve supplies the mandibular incisors and canines?
Incisive branch of inferior alveolar nerve (CN V3)
207
What nerve supplies the mandibular premolars and molars?
Dental branches of inferior alveolar nerve (CN V3)
208
What is the arterial supply to the maxillary teeth?
Branches of maxillary artery:
- Anterior superior alveolar artery
- Posterior superior alveolar artery
209
What is the arterial supply to the mandibular teeth?
Inferior alveolar arteries (from maxillary artery)
