Exam 3 anatomy and diseases

Question 1

SCALP

Answer 1

Composed of 5 layers –The first letter of each layer spells “SCALP”

S Skin
C Connective tissue (Dense) 
A Aponeurosis – (galea aponeurotica)
L Loose connective tissue 
P Pericranium-periosteum of skull

The scalp proper- The first three layers (Skin, Connective tissue, and Aponeurosis) is called the scalp proper. They are tightly held together and move as a unit (e.g., when wrinkling the forehead and moving the scalp).

Skin- contains sweat, sebaceous glands and hair follicles.

Connective tissue (Dense) – contains the blood vessels of the scalp. Arterial walls are firmly attached to connective tissue.

Aponeurosis –galea aponeurotica of the epicranial muscles frontalis an occipitalis.

  Loose connective tissue - called dangerous 	area 
-Includes potential spaces (may fill with fluid from 	injury or infection)

- Contains emissary veins that 	communicate with the 	dural sinuses within 	the cranium.
- Can pass infections intra cranially

Pericranium-periosteum of skull

Question 2

Scalp Lacerations

Answer 2

severe bleeding because the arteries in the second layer of the scalp (connective tissue layer) cannot retract and are held open

superficial lacerations do not gape because its margins are held together by aponeurosis (third layer of scalp)

deep transverse scalp lacerations gape widely owing to the pull of the frontal and occipital parts of the epicranial muscle in opposite directions .

Question 3

Scalp Infections

Answer 3

Infections in 4th layer of scalp (Loose connective tissue)-

can be transmitted to the-

	- cranial cavity (brain and meninges) through the emissary veins 
	- the eyelids and root of nose because frontalis attached to skin and 		subcutaneous tissue, “black eyes”

cannot pass into the -

	- neck because occipitalis attached to occipital and temporal bones
	- laterally beyond the zygomatic arches because epicranial 			aponeurosis continuous with temporal fascia that attached to the zygomatic arches

Question 4

Trigeminal Neuralgia

Answer 4

Characterized by episodes of brief, intense facial pain over one of the three areas of CN V distribution

Pain is so intense that patient winces, which produces a facial muscle tic

Etiology: uncertain
Usually affects Maxillary (V2) or Mandibular (V3) nerve unilaterally
Usually in those older than 50

Triggers: touch or draft of cool air

Question 5

Bell’s Palsy

Answer 5

Injury to facial n. or branches causes paralysis of the facial mm. (Bell’s Palsy), with or without loss of taste to anterior 2/3 of tongue or altered secretion of the lacrimal and salivary glands.

Location of lesion and structures affected:

1. Near origin from pons or geniculate ganglion – loss of motor, gustatory (taste) and autonomic functions (secretions)
2. Distal to geniculate ganglion, but proximal to origin or chorda tympani n. – same dysfunctions, but lacrimation is not affected
3. Near stylomastoid foramen or Parotid gland – loss of motor function only

The most common cause :

Inflammation of the facial n. near the stylomastoid foramen - Swelling from viral infection can compress nerve

Injury to the facial nerve may result from fracture of temporal bone.

Damage may occur during surgical procedures involving the parotid gland or infection of the middle ear

Question 6

Lesion of zygomatic branch of facial nerve

Answer 6

Loss of tonus of orbicularis oculi –

Inferior eyelid everts (falls away from eye)
Lacrimal fluid will not spread over cornea
Cornea is vulnerable to ulceration

Question 7

Lesion of buccal and marginal mandibular branches

Answer 7

Weakened/paralyzed buccinator and/or orbicularis oris mm.
Allows food to accumulate in oral vestibule-requires constant removal with finger
Corners of the mouth droop due to contraction of contralateral facial mm. and gravity
Food and saliva can dribble out of mouth

Weakened lip mm. –
Can affect speech
Impaired ability to produce B, M, P or W sounds
Cannot whistle or blow

Patients are constantly wiping face or eyes (to get rid of tears and saliva), May result in localized skin irritation

Question 8

Injury To Facial Nerve (upper motor neuron lesion)

Answer 8

Central facial palsy- Paralysis or Paresis of the lower half of one side of the face. It usually results from damage to upper motor neurons (motor cortex).

Question 9

Injury to facial nerve (A lower motor neuron lesion- )

Answer 9

paralysis of facial muscles (both upper and lower face)on the same side of the injury-is known asBell’s palsy.

If a cause, such as trauma or infection, cannot be identified - this situation is calledidiopathic palsy). Otherwise it is described by its cause.

Question 10

dangerous triangle of the face

Answer 10

Infections of the facial vein spreading to the cavernous venous sinuses may result from lacerations of the nose, or be initiated by squeezing pustules on the side of the nose and upper lip. This is called dangerous triangle of the face (from the root of the nose to the angles of the mouth)

Question 11

The Temporal Fossa

Answer 11

bounded by the superior temporal line (posteriorly and superiorly), the frontal and zygomatic bones (anteriorly), the infratemporal crest (inferiorly), and the zygomatic arch (laterally)

Contents of the temporal Fossa :

Superior portion of temporalis muscle and its covering temporal fascia

Deep temporal nerves and vessels

Auriculotemporal nerve- provides parasympatheric/secretomotor fibers to the parotid gland, and somatosensory to the superficial temporal region.

Superficial temporal vessels

Question 12

The infratemporal fossa

Answer 12

Bounded by the ramus of the mandible (laterally), the angle of the mandible (inferiorly), the tympanic plate and styloid process (posteriorly), the lateral pterygoid plate (medially), the posterior aspect of the maxilla (anteriorly), and the inferior surface of the sphenoid bone (superiorly)

Contents of the infratemporal fossa:

Muscles-
Inferior part of the temporalis muscle.
Lateral and medial pterygoid muscles.

Arteries-
Maxillary artery and its branches

Veins-
Pterygoid venous plexus

Nerves-
Mandibular n. (CNV3) and its branches

Chorda tympani nerve ( branch of Facial nerve)

Otic ganglion (cranial parasympathetic ganglion-CNIX)

Question 13

Pterygopalatine fossa

Answer 13

The contents of the pterygopalatine fossa :

The maxillary artery (pterygopalatine or third part), and the initial parts of its branches, and accompanying veins.

Maxillary nerve (CN V2)

&

its branches

Pterygopalatine ganglion

Pterygopalatine fossa connected with:

Orbit- via inferior orbital fissure 

Nasal cavity- via sphenopalatine foramen

Oral cavity via greaterpalatine canal

 Middle cranial fossa  via foramen rotundum (maxillary nerve)

Infratemporal fossa via pterygomaxillary fissure

Question 14

Maxillary Nerve Block

Answer 14

Extensive dental surgery may require total nerve block of the maxillary branch of the trigeminal nerve (CNV2). Themaxillary nerve in the pterygopalatine fossa is most often approached intraorally viathegreater palatine canal.

Question 15

Chronic Epistaxis

Answer 15

The sphenopalatine artery is often referred to as the artery ofepistaxis(nosebleed). In cases of chronic epistaxis, the pterygopalatine fossa can be surgically approached via the maxillary sinus, and the artery ligated to control bleeding.

Question 16

Maxillary Artery

Answer 16

Subdivided into three parts:
1st or mandibular part- Deep to mandible

2nd or pterygoid part- Superficial or deep to lateral pterygoid muscle

3rd or pterygopalatine part- Enters pterygomaxillary fissure into pterygopalatine fossa.

Mandibular Part

Deep auricular 
Anterior tympanic
Middle meningeal
Inferior alveolar

2nd or
Pterygoid Part

Muscular branches

3rd or 
Pterygopalatine Part

Posterior superior alveolar
Infraorbital
Artery to pterygoid canal
Pharyngeal branch
Descending palatine 
Sphenopalatine 
terminal branch

Question 17

Mandibular Nerve

Answer 17

Branches

1. Motor branches- to muscles of mastication
2. Auriculotemporal: somatosensory to the superficial temporal regions, TMJ. parasympathetic/secretomotor fibers (carries from otic ganglion) to parotid gland.
3. Lingual: sensory to the anterior two thirds of the tongue, the floor of the mouth, and the lingual gingivae.
4. Inferior alveolar : Enter Mandibular canal through mandibular foramen along with inferior alveolar artery and vein.The mental nerve: branch of the inferior alveolar nerve) passes through the mental foramen.

Supplies the skin and mucous membrane of the lower lip, skin of the chin, and the vestibular gingiva of the mandibular incisor teeth.

5. Buccal: sensory to the skin over buccinator muscle, mucous membrane of cheek and gums.

Question 18

The chorda tympani nerve

Answer 18

The chorda tympani nerve and otic ganglion -Located in the infratemporal fossa :
The chorda tympani nerve -a branch of the CN VII facial nerve joins the lingual nerve in the infratemporal fossa.

Carrying taste fibers from the anterior two thirds of the tongue.

Supplies parasympathetic/secretomotor fibers to the submandibular and sublingual gland.

Question 19

Otic ganglion

Answer 19

Otic ganglion- Parasympathetic ganglion lies just inferior to foramen ovale

Presynaptic parasympathetic fibers from CN-IX (glossopharyngeal) nerve synapse in the otic ganglion.

 Postsynaptic parasympathetic fibers from otic ganglion pass through the auriculotemporal nerve to parotid gland (secretomotor).

Question 20

pterygopalatine ganglion

Answer 20

Thepterygopalatine ganglion (Meckel’s ganglion, nasal ganglion or sphenopalatine ganglion)is one of four parasympatheticgangliaof the head and neck.. It is located in the pterygopalatine fossa.

The pterygopalatine ganglion supplies:

Secretomotor/parasympathetic and vasoconstrictive/ sympathetic fibers to-
Lacrimal, nasal, palatine, and pharyngeal glands

Sensory fibers to –
the mucosa of nasal cavity, palate and uppermost pharynx.

Question 21

4 parasympathetic ganglions:

Answer 21

C The ciliary ganglion - associated with CN:III (3)
Supplies- ciliary and constrictor pupillae, accommodation for near vision. Via Short Ciliary nerve

O The Otic ganglion -associated with CN: IX (9)
Supplies-Parotid gland ( saliva) via auriculotemporal n.

P The pterygopalatine ganglion - associated with CN:VII (7)
Supplies- Lacrimal gland (Tear and mucosal glands of oral and nasal cavity- mucous production)

S The submandibular ganglion - associated with CN:VII (7)
Supplies- Submandibular and sublingual salivary glands ( saliva) via chorda tympani n.

COPS

Question 22

Dislocation of TMJ

Answer 22

Causes:
Yawning
Large bite
Excessive contraction of lateral pterygoids muscle.
Depressed mandible (can not close mouth)
Anterior-the heads of the mandibles to dislocate anteriorly
Posterior dislocation is uncommon.

Question 23

Arthritis of TMJ

Answer 23

Inflammation from degenerative arthritis
Dental occlusion problems and joint clicking

Injury to articular branches of the auriculotemporal nerve (Associated with traumatic dislocation and rupture of the joint capsule and lateral ligament)—
leads to laxity and instability of the TMJ.

Question 24

Cleft Palate

Answer 24

Can be w/ or w/o cleft lip.
Occurs in ~1/2500 births and more common in females than men
May involve only the uvula or may extend through the soft and hard regions of the palate.

Congenital
About a 3% chance that their children will have it.

Because of the gap, there is a hyper nasal resonance of the voice.
May also experience ear infections, feeding problems, and teething issues

May require speech therapy later in life or surgery.

Question 25

Tongue Gross Features:

Answer 25

Sulcus Terminalis or Terminal sulcus - a V-shaped groove that divides the anterior 2/3 of the tongue in mouth from the posterior 1/3 in oropharynx

Foramen Cecum - located at the apex of the sulcus terminalis.
Is an embryological remnant of the thyroid gland and a site of upper end of the thyroglossal duct in the embryo

Lingual Papillae and Taste Buds - papillae are located on the dorsum of the tongue.

The Lingual Tonsil is on the posterior one third of the dorsum of the tongue.

Inferior/under surface of the tongue

The frenulum of the tongue- A single median mucosal fold is continuous with the mucosa covering floor of the oral cavity. It allows the anterior part of the tongue move freely. A deep lingual vein is visible on each side of the frenulum.

Sublingual caruncle (papilla)- on each side of the base of the frenulum, It contains the opening of duct from the submandibular glands.

Sublingual fold - contains many openings of ducts from the sublingual glands.

Question 26

Muscles of the tongue

Answer 26

A. Extrinsic M. (attaching the tongue to something else)
B. Intrinsic M. (inside the tongue)

Extrinsic M. (attaching the tongue to something else)-Move tongue

Palatoglossus M.- Elevates the tongue and depresses the soft plate.

Styloglossus M.- Retrudes tongue and curls (elevates) its sides

Hyoglossus M.-Depress tongue, pulling sides inferiorly, Shortens tongue.

Genioelossus M.- Bilateral - depresses tongue, creating central longitudinal furrow, and protrude tongue. Unilateral – deviates tongue to contralateral side

Intrinsic M. (inside the tongue)
Change shape of tongue

• Inferior and Superior Longitudinal Muscle
• Transverse Muscle
• Vertical Muscle

Question 27

Innervation to the Tongue

Answer 27

Motor:
All extrinsic and intrinsic muscles are supplied by Hypoglossal N. CN XII (except palatoglossus in. – CN X)

2. General Sensation:

Anterior 2/3: lingual n., br. of V3

b. Posterior 1/3: CN IX Glossopharyngeal N.
c. epiglottis: CN X Vagus N.

3. Special Sensation (Taste):

a. anterior 2/3: CN VII, chorda tympani n.
b. posterior 1/3: CN IX Glossopharyngeal N.
c. epiglottis: CN X Vagus N.

Question 28

Lymphatic Drainage of the tongue

Answer 28

Posterior third– Sup. Deep cervical lymph nodes

Medial part of the anterior two thirds– Inferior deep cervical lymph nodes

Lateral part of anterior two thirds— Submandibular lymph nodes

Apex and frenulum– submental lymph nodes

Question 29

Lingual Carcinoma

Answer 29

In the posterior part of the tongue

Metastasizes in the deep cervical lymph nodes on both sides

Question 30

Sublingual Absorption of Drugs

Answer 30

Used for quick absorption
Medication dissolves and enters the deep lingual veins in less than a minute

Eg. Nitroglycerine for angina pectoralis, or any other drug that dissolves in saliva

Question 31

Frenectomy

Answer 31

Overly large lingual frenulum

Can interfere with tongue movements and speech

Question 32

Paralysis of the Genioglossus

Answer 32

When the genioglossus muscle is paralyzed, the tongue tends to fall posteriorly.
It can obstruct the airway and present the risk of suffocation.
Total relaxation during anesthesia, so an airway is inserted to prevent the tongue from relapsing.

Question 33

Injury to Hypoglossal Nerve

Answer 33

May result in paralysis or atrophy of one side of the tongue.

Deviates to the paralyzed side during protrusion.

Question 34

Salivary Glands

Answer 34

A. Parotid Glands –
located in the retromandibular region.

Parotid duct opens opposite the upper 2nd molar tooth

B. Submandibular Glands –

lies along the body of the mandible (partly deep and partly inferior to the mandible)

within the submandibular triangle in the neck.

Submandibular duct or Wharton duct passes at the midportion of the triangle and lingual nerve passes under the duct

Submandibular duct empties into the mouth at the sublingual caruncle.

C. Sublingual Glands - located deep to the sublingual fold in the mouth. Its numerous ducts opens onto the sublingual fold.

Innervation :

Submandibular and sublingual salivary glands —
-parasympathetic secretomotor fibers of the chorda tympani n ( from Facial n. CN VII) that travel with the lingual n.

Parotid gland—
parasympathetic secretomotor fibers of the glossopharyngeal n. (CN IX) that travel with the auriculotemporal n ( a branch of mandibular n.).

Question 35

Infection of Parotid Gland

Answer 35

The parotid gland may become infected by infectious agents -as occurs in mumps.

The mumps virus also may cause inflammation of the parotid duct, producing redness at the opening of the duct into the superior oral vestibule.

Because the pain produced by mumps may be confused with a toothache.

Parotid gland disease often causes pain in the auricle, external acoustic meatus, temporal region, and temporomandibular joint (TMJ) because the auriculotemporal nerve, from which the parotid gland receives sensory fibers, also supplies sensory fibers to the skin over the temporal fossa and auricle.

Question 36

Parotiditis

Answer 36

Parotid abscess
Bacterial infection of the parotid glands.
Often caused by poor dental hygiene.

Question 37

Parotidectomy

Answer 37

80% of salivary gland tumors occur in the parotid glands
Surgical excision of the parotid gland is often performed as part of treatment
It is important to identify, isolate, and preserve the facial nerve during surgery.

Question 38

Sialolith

Answer 38

Sialolith ( blockage of the parotid duct)

Sialoliths, or salivary stones, are the most common disease of the salivary glands in middle-aged patients.

More than 80% of salivary sialoliths occur in the submandibular duct or gland,
6 to 15 % occur in the parotid gland

2% are in the sublingual and minor salivary glands.

Sialography
Injection of radio opaque fluid into salivary gland duct (parotid and submandibular).
Due to small size of sublingual gland duct sialography is not usually performed.
Used for visualization of the duct in disease states

Question 39

Innervation of the head muscles Rules

Answer 39

Rule 1
If a muscle has “tensor” in its name, it is innervated by V3, the mandibular division of Trigeminal i.e., tensor tympani, tensor veli palatini

Rule 2
If a muscle has “palat-“ in its name, it is innervated by CN X, Vagus, unless Rule 1 applies. i.e., palat oglossus, levator veli palat ini, (there are more) but NOT tensor veli palatini.

Rule 3
If a muscle has “glossus” in its name – it is innervated by CN XII – Hypoglossal, unless Rule 2 applies. E.g., stylo glossus , genio glossus, hyoglossus, but NOT palatoglossus

Question 40

Fascia of the neck

Answer 40

1. Superficial cervical fascia
   
   2. Deep cervical fascia
2. Superficial fascia of the Neck
   Superficial cervical fascia-
   Deep to the skin a thin layer of subcutaneous tissue.

It contains- cutaneous nerves, blood vessels, lymph vessels and Platysma muscle.

Platysma m.- covers the anterolateral aspect of the neck.

2. Deep Cervical Fascia-

Deep to the superficial layer is the membranous deep cervical fascia.

4 layers/sheaths of deep cervical fascia are-
Investing layer- surrounds trapezius and SCM
Prevertebral layer- surrounds cervical vertebral column and muscles associated with it
Carotid sheath- surrounds internal carotid, internal jugular, and vagus n
Pretracheal layer- surrounds infrahyoid, thyroid gland, larynx, and trachea

These layers surrounds and supports the cervical muscles and viscera.

Question 41

Tissue spaces

Answer 41

The space between the fascial layers of the neck defines a number of potential ‘spaces’ .

Retropharyngeal Space-
Lies posterior to pharynx and esophagus.
It is bounded:
Anteriorly-bucccopharyngeal (continuation of pretracheal fascia) fascia
Posteriorly-prevertebral fascia (prevertebral muscles)
Laterally -carotid sheath.

This space opens inferiorly into the mediastinum to the level of the diaphragm.

It permits movements of pharynx, esophagus, larynx & trachea during swallowing.

It divided into two space by alar fascia- true retropharyngeal space and danger space.

Clinical significance- infections can easily spread above downwards.

Prevertebral space-situated between the prevertebral fascia anteriorly and the vertebral bodies posteriorly. It extends from the skull base to the coccyx.

Question 42

Major triangle divisions of the Cervical Regions

Answer 42

Posterior Triangle or (lateral cervical region)-

Bounded by posterior border of the SCM and anterior border of the trapezius muscle.

B. Anterior Triangle-

Bounded by the anterior border of SCM and anterior mid line of the neck.

Question 43

Posterior Triangle divisions

Answer 43

Posterior

Contains: Occipital
CNXI (Spinal accessory), Trunks of brachial plexus

Clinical significance: Swollen lymph nodes in the posterior triangle may irritate this nerve, producing spasmodic torticollis. Lesion to the CNIX- inability to shrug the shoulder.

Subclavian

Contains: 3rd part of subclavian artery
Arterial pulsation

Clinical significance: Pressure point- Compression of 3rd part of subclavian artery against 1st rib can control bleeding of the upper limb

Question 44

Anterior Triangle divisions

Answer 44

Submental

Contains: Lymph nodes, small veins

Submandibular

Contains: Submandibular gland, CNXII (hypoglossal),

Clinical significance: glandular area

Carotid

Contents: Carotid sheath containing common carotid artery and its branches, internal jugular vein and vagus nerve

Clinical significance: vascular area/ Carotid Pulse or neck pulse

Muscular

Contents: Thyroid and parathyroid glands, sternothyroid and sternohyoid M.

Question 45

Torticollis

Answer 45

Wry Neck
means a twisted neck.

Spasmodic torticollis-
Occurs in adults

Characterized by unilateral spasms of the sternocleidomastoid and trapezius muscles and possibly the deeper muscles of the neck.

Congenital torticollis-

Results from damage to the sternocleidomastoid muscle following a difficult delivery.

Damaged muscle fibers and a hematoma develop into scar tissue that causes spasm.

The neck is pulled to the ipsilateral side, and the face is turned to the contralateral side

Question 46

strap muscles

Answer 46

(below the hyoid bone)

Sternohyoid

Sternothyroid

Thyrohyoid

Omohyoid

Question 47

Carotid sinus and Carotid body

Answer 47

Carotid sinus-
Is dilatation located at the origin of the internal carotid artery,
which functions as a pressoreceptor (Baroreceptor) reacts with arterial pressure.
Innervated by a branch of glossopharyngeal and a branch of vagus nerve.

Carotid body-
Lies at the bifurcation of the common carotid artery as an ovoid body.
Is a Chemoreceptor-monitors oxygen level in blood.
Is stimulated by the low level of oxygen and initiates reflexes that increase the rate and depth of respiration, cardiac rate and blood pressure.

Question 48

Lymph drainage of the Head and Neck

Answer 48

Superficial Lymph Nodes are:

1. Occipital:from the occipital area of the scalp.
2. Mastoid/retro auricular: from the posterior neck, upper ear and the back of the external auditory meatus (the ear canal).
3. Parotid:fromthe nose, the nasal cavity, the external acoustic meatus, the tympanic cavity and the lateral borders of the orbit,nasal cavities and the nasopharynx.
   Buccal/fascial-
4. Submental:from the central lower lip, the floor of the mouth and the apex of the tongue.
5. Submandibular: from the cheeks, the lateral aspects of the nose, upper lip, lateral parts of the lower lip, gums and the anterior tongue. They also receive lymph from the submental and facial lymph nodes.
6. Superficial Cervical:lie along external jugular vein and collect lymph from superficial surfaces of the neck.

Deep Lymph Nodes:

The deep (cervical) lymph nodes: receive all of the lymph from the head and neck –either directly or indirectly via the superficial lymph nodes.

Question 49

Thyroid Ima Artery

Answer 49

Artery-Small, unpaired artery arising from brachiocephalic trunk, arch of aorta, right common carotid, subclavian, or internal thoracic arteries. Runs along anterior trachea and enters isthmus of thyroid gland.

Approximately 10% of people. Keep in mind during surgery.

Question 50

Goiter

Answer 50

Enlargement of thyroid gland: Goiter
During menstruation and pregnancy( non – neoplastic and noninflammatory enlargement)
Lack of Iodine

Swelling of the neck
Compress the trachea, esophagus, and recurrent laryngeal nerve

Question 51

Thyroidectomy

Answer 51

Surgeons try to preserve the posterior lobes of the thyroid during thyroidectomy or isolate the parathyroid glands if all of the thyroid must be removed.

Question 52

Injury to the Recurrent Laryngeal Nerves

Answer 52

Closely related to the inferior pole of the thyroid, pass along with inferior thyroid artery,
Can result in post-operative hoarseness, aphonia, dysphonia, and laryngeal spasm.

Question 53

Ectopic Thyroid

Answer 53

Lingual thyroid gland - Occurs when the gland fails to descend from its embryonic position in the tongue.
Incomplete descent – locations high in the neck, or just below the hyoid
bone can be confused for a thyroglossal duct cyst.

Question 54

Thyroglossal Duct Cyst

Answer 54

Cystic remnant of the thyroglossal duct. (Thyroglossal duct usually disappears)

Associated with development of the thyroid gland

May be found at the root of the tongue

Most common congenital anomaly of the neck. Equal girl/boy occurence

2-4% of all neck masses. 7% population prevalence

Question 55

palatine tonsil inflamation

Answer 55

The palatine tonsils can becomes inflamed due to a viral or bacterial infection.
A swollen tonsil may compress the glossopharyngeal nerve against the styloid, with pain referred to the pharynx and ear.

Chronic infection can be treated with their removal, a tonsillectomy. `Glossopharyngeal nerve is vulnerable to injury

Question 56

Emergency Tracheotomy

Answer 56

Cricothyroid ligament/membrane- connects cricoid and thyroid cartilages. This ligament is cut during emergencyairway puncture (Emergency Tracheotomy). It is below the vocal fold level.

Question 57

Damage to recurrent laryngeal nerves

Answer 57

close to inferior thyroid artery, so at risk during surgery; also in lung cancer, thyroidcancer, aortic anuerism, etc

unilateral palsy results in one vocal cord being paralyzed; can lead to hoarseness of voice

bilateral palsy closes the rima glottis (opening between vocal cords), impairing breathing and requires emergency surgery intervention to restore airway

Question 58

Cancer of Larynx

Answer 58

The incidence of cancer of the larynx is high in individuals who smoke cigarettes or chew tobacco.

Most persons present with persistent hoarseness, often associated with otalgia (earache) and dysphagia.

Enlarged pretracheal or paratracheal lymph nodes may indicate the presence of laryngeal cancer.

Question 59

Eyelids

Answer 59

• Contains medial and lateral canthus (corners of eye), upper and lower eyelid, and palpebral fissure where they eye can be seen through the eyelids
• Formed by cartilage structures- the superior and inferior tarsus
• Has ligaments on the corners called the lateral and medial palpebral ligaments
• Covering is called conjunctiva
  
  • Extends over the inner aspect of the lid and covers the surface of the eye
  • The palpebral conjunctiva on the inside of the eyelids folds back at the superior and inferior conjunctival fornix and runs on the surface of the eye ball, then called th palpebral conjunctiva
  • Also have eyelashes and sebaceous glands in the eyelids
  • On inner eyelid, there are palpebral glands that are modified sweat glands

Question 60

styes

Answer 60

• Infected sabaceous glands of the eyelids are called styes

Question 61

chalazions

Answer 61

• Infection of the tarsal glands are further away from the eyelid boarders and are called chalazions

Question 62

• Lacrimal apparatus

Answer 62

• The lacrimal gland is superior and lateral to the eye and has an orbital and a palpebral part
• Tears run from the lacrimal gland infra medially to the lacrimal canaliculi which are connected to the lacrimal sac and the nasolacrimal duct where they enter the nasal cavity
• Excess tears escape the eyes and run down the face
• Inneration:
  
  • PSNS is done from CN VII in the pons, through the pterygopalatine ganglion, through piggybacking on trigeminal nerve branches to the lacrimal gland. It goes to the lacrimal gland through the lacrimal nerve, but the lacrimal nerve is from CN V, so if asked where the innervation of PSNS of lacrimal gland comes from, CN VII (facial nerve) is correct, not lacrimal nerve
  • SNS is done by T1-2 of spinal cord to superior cervical ganglion, through nerves, and to lacrimal gland. Piggybacks through maxillary nerve to lacrimal nerve, but is separate from the lacrimal nerve

Question 63

Oculomotor nerve paralysis

Answer 63

eye deviates laterally because the lateral rectus is only major muscle still working

Question 64

Trochlear nerve paralysis

Answer 64

eye is in extorsion and adduction because the superior oblique is paralyzed. Also leads to upward deviation; patient rotates head and looks to the opposite side as the affected side

Question 65

Abducens nerve paralysis

Answer 65

head turned to involved side to focus the image on the corresponding points. Due to lateral rectus paralysis

Question 66

Orbital floor injury

Answer 66

limitation of upward gaze caused by entrapment of fracture defect. Can lead to infection from transmission of the bacteria in the teeth/oral cavity. Causes clouding on radiology due to prolapse of orbital fat body and muscle

Question 67

Chronic Sinusitis

Answer 67

> 3 months
Mucosal thickening is the hallmark, often circumferentially
Can involve one or several sinuses
Over years can slowly develop reactive sinus wall bony sclerosis and thickening and sinus shrinkage

Question 68

Acute Sinusitis

Answer 68

< 1 month
Layering fluid is the hallmark, sometimes with frothy bubbles
Can involve one or several sinuses
Can have acute mucosal thickening or be superimposed upon chronic disease

Question 69

Sinonasal Polyposis

Answer 69

Most common in ethmoid and maxillary sinuses and nasal cavity
Often results in complete sinus opacification, expands maxillary sinus ostium, +/- expansion of maxillary or ethmoid sinuses or nasal cavity
Antrochoanal polyps extend posteriorly from the maxillary antrum through the nasal cavity and past the choana into the nasopharynx

Question 70

Orbital Abscess Caused by Acute Sinusitis

Answer 70

Orbital subperiosteal abscess development can be a complication of acute ethmoid or frontal sinusitis (but seldom maxillary sinusitis b/c thicker bony wall along orbital floor)
The medial orbital wall (ethmoid lamina papyracea) is quite thin and porous, which can facilitate the intraorbital migration of bacteria in cases of ethmoid sinusitis
Intraorbital abscesses tend to displace intraocular structures such that the globe moves anteriorly and away from them, often causing diplopia
Imaging findings consist of
Nearby sinus opacification
A centrally non-enhancing pus pocket with rim enhancement that abuts the orbital wall peripheral to the extraocular muscle cone
Displacement of the muscle cone and globe away from the abscess and protrusion of the globe too far anteriorly (proptosis)
Periorbital and extraconal intraorbital inflammatory soft tissue stranding elsewhere

Question 71

Thyroid Associated Orbitopathy

Answer 71

Thyroid associated orbitopathy (TAO) is the most common cause of bulging eyes (aka proptosis or exophthalmos)
Is most frequently associated with Graves disease, but rarely is present with Hashimoto thyroiditis
Can cause optic nerve compression at the orbital apex when severe, potentially leading to blindness
In an abnormal immune response the extraocular muscles (EOMs) are infiltrated with inflammatory cells (lymphocytes, macrophages, plasma cells and eosinophils), and increased mucopolysaccharide deposition
Imaging characteristics are
Enlargement of the extraocular muscle (EOM) bellies with sparing of their tendinous insertions Involvement is more common and more pronounced for inferior > medial > superior > lateral rectus muscles
Proptosis (exophthalmos)
Increased intraorbital fat volume overall (this contributes to proptosis) and fatty infiltration of the EOM muscles over time
Usually bilateral (70-90%) and symmetrical (70%)
No significant contrast enhancement

Question 72

Thyroglossal Duct Cyst

Answer 72

Thyroglossal duct cysts (TGDC) are the most common congenital neck anomaly (70%) and are the most common midline neck mass in young patients.
They typically present during childhood (90% before the age of 10), or remain asymptomatic until they become infected, in which case they can present at any time.
They are the second most common benign neck mass, after lymphadenopathy.
The cysts can occur anywhere along the course of the thyroglossal duct, although the infrahyoid location is most common:
suprahyoid: 20-25% (less common in adults ~5%)
at the level of hyoid bone: ~30% (range 15-50%)
infrahyoid: ~45% (range 25-65%)
(Anterior surgical triangle & visceral space)
Typically, they are located along the anterior midline (~70%) or just off midline.
On CT and MRI they have a fairly simple appearance, with minimal thin wall enhancement, sometimes embedded in the strap muscles
They can become thick-walled and more complex when infected

Question 73

Branchial Cleft Cyst

Answer 73

Cysts arising along embryologic branchial cleft fistula tract remnants
2nd branchial cleft cysts are by far most common (95%), so they account for all examples in this DSA
They usually present as a neck mass in childhood, or they will present at any age if they become infected
Located in anterior surgical triangle laterally and the carotid space, anteromedial to the sternocleidomastoid muscle
By imaging are usually circumscribed unilocular cysts with only minimal rim contrast enhancement, but can become multilocular & complex if infected

Question 74

Lymphangioma

Answer 74

Lymphangiomas are benign lesions of vascular origin that show lymphatic differentiation (the lymphatic equivalent of a hemangioma of blood vessels)
The vast majority are located in the neck or axillary regions (95%)
In the neck they are in the posterior surgical triangle and posterior cervical space, located posterolateral to the sternocleidomastoid muscle
They can present at any age, but most often occur in the pediatric population (~90% in those less than 2 years old).
On imaging they typically have a multiloculated cystic appearance without significant contrast enhancement – they can be quite large

Question 75

Rupture of the Tympanic Membrane

Answer 75

The tympanic membrane can be ruptured by material within the external acoustic meatus.
An ear infection, especially in children, can damage the tympanic membrane.
Head trauma and a loud noise can induce a perforated tympanic membrane.

Question 76

Acute otitis externa

Answer 76

Acute otitis externa, also called swimmer’s ear, is an inflammation, infection, or edema of the external acoustic meatus and its walls.

Question 77

The Middle Ear (The tympanic cavity)

Answer 77

Middle ear connects :

    Anteromedially-  with the nasopharynx via pharyngotympanic/Auditory tube  

   Posterosuperiorly- with the mastoid air cells via the mastoid antrum.

Contents:
Auditory ossicles/ bones (three) (lateral to medial):
1. Malleus (Latin. a hammer)

 2. Incus ( L. an anvil) 
3. Stapes (L. a stirrup)

2 muscles:
1. Tensor tympani

2. Stapedius

1. Roof(tegmental wall), 2. Anterior wall (carotid wall), 3. Posterior wall (mastoid wall)
2. Floor(jugular wall) 5. Lateral wall (membranous wall) 6. Medial wall (labyrinthine wall)

Roof (tegmental wall):

A thin plate of bone, called tegmen tympani

It separates the tympanic cavity from the dura matter of the middle cranial fossa.

Floor (jugular wall):

It separates the tympanic cavity from the superior bulb of the internal jugular vein

Carotid Wall (Anterior Wall):

Opening for the tensor tympani muscle tendon above
Opening of the Auditory or pharyngotympanic tube lies in the middle
The inferior part is separated from the internal carotid artery

Mastoid Wall (Posterior Wall):

Opening or aditus through which middle ear communicates with mastoid or tympanic antrum.

The tendon of the stapedius muscle passes through the junction of the posterior and medial walls.

Canal for CN VII facial n. descends between wall and antrum.

Lateral wall (membranous wall):
The tympanic membrane.
The handle of the malleus is attached to the tympanic membrane.

Medial Wall (Labyrinthine Wall): It Separate the tympanic cavity from the inner ear.
Features –
The promontory- a bulging produced by the first turn of the cochlea.

The oval window - closed by the foot plates /base of the stapes. Scala Vestibule of cochlea begins at oval window.

The round window- is inferior to the promontory. It is closed by a secondary tympanic membrane. Scala Tympani of cochlea terminates at round window.

The prominence of the facial canal just above the oval window, it transmits CN VII (Facial nerve).

Question 78

Skeletal Muscles associated with Osscles:

Answer 78

Tensor Tympani m. –
Origin from the auditory tube and adjoining bone
It inserts on the handle of the malleus.
Prevent damage to inner ear when exposed to loud sounds
Innervated by a branch of CN V 3 (Mandibular nerve).
During Chewing-
Pulls handle of malleus medially to tense tympanic membrane and pulls the membrane inward.
Therefore it reduces vibration of the malleus in response to noise produced by chewing.
Note: Mandibular nerve injury produce hyperacusis (mainly to the sound produced from chewing).

Stapedius m. –
Its tendon inserts near the posterior surface of the neck of the stapes (ear osscicles).
It pulls the stapes posteriorly into the oval window and prevents excessive movement of the stapes.
Innervated by a branch of CN VII (Facial nerve).
Action: damping effect on sound waves
Loss of damping effect results in hyperacusis
The Attenuation Reflex

Loud sound causes tensor tympani and stapedius muscle contraction.
Stepedius muscle reduces the vibration of the stapes.
Paralysis of this muscle as result of facial nerve palsy, produce hyperacusis (whereby normal sounds are perceived as annoyingly loud).

Question 79

Otitis Media

Answer 79

Is an inflammation of the middle ear.
Infection can damage auditory ossicle- can cause- hearing loss: prolonged infection can spread through the Tegmen tympani (roof ) to brain.

Note: Ear infections are more common in children (<15 years of age) because the tube is horizontal and shorter, which limits drainage by gravity, thus providing a route for infection from the nasopharynx.

Question 80

Mastoiditis

Answer 80

Infections of the mastoid antrum and mastoid cells (mastoiditis) result from a middle ear infection that causes inflammation of the mastoid process).
During operations for mastoiditis, surgeons are conscious of the course of the facial nerve to avoid injuring it.
At present, most mastoidectomies are endaural (incision through the external auditory canal)

Question 81

Blockage of Auditory/Pharyngotympanic Tube:

Answer 81

The infection to pass from the nasopharynx to the middle ear or tympanic cavity.
This tube is easily blocked by swelling of its mucous membrane, even as a result of mild infections (e.g., a cold), because the walls of its cartilaginous part are normally already in apposition.

Question 82

Ménière’s disease

Answer 82

The cause of Ménière’s disease is thought to result from an increase in the volume of endolymph, thus this disorder is also called idiopathic endolymphatic hydrops.
A rupture of the membranous labyrinth may allow endolymph to mix with perilymph.
The disorder can lead to destruction of the hair cells within the inner ear, thus hearing loss.
Some of the symptoms include dizziness, tinnitus, pressure in the ear, loss of hearing and nausea.
Sensitivity to visual stimuli can cause the eyes to jump, termed nystagmus.

Question 83

Otosclerosis

Answer 83

Bone deposition at the oval window, called otosclerosis, can fuse the stapes to this site, resulting in hearing loss.

Question 84

Kiesselbach plexus (Little’s area)

Answer 84

located on the anterior nasal septum
formed by anastomosis of septal branches of 4 arteries: 
ethmoidal aa.
sphenopalatine a.**
superior labial a.**
greater palatine a.
**largest contributors
exposed to drying effect of inspired air that predisposes it to crack and bleed
site of 90% of epistaxis