Anatomy: Face, Scalp, Parotid gland

Question 1

5 layers of skin?

Answer 1

S: skin
C: CT - dense - contains vessels and nn.
A: aponeurosis epicranius
L: loose CT - usually this is plane during scalp injury
P: pericranium (periosteum, outer CT of flat bones of skull)

Question 2

why do scalps bleed so much?

Answer 2

scalp is highly vascular and because the vessels are embedded within the dense ct of layer 2 there is limited constriction when lacerated. There are many anastomoses as well, and there is no single vessel to compress to stop the bleeding.

Question 3

how is scalp innervated?

Answer 3

spinal nerves posterior portion of head

trigeminal n. anterior portion of head

Question 4

what are spinal nn. innervating scalp?

Answer 4

greater occipital: straight middle back of head
C3: inferior posterior scalp
Lesser occipital: behind ear
great auricular: underneath ear

Question 5

what cranial nn. innervate scalp?

Answer 5

Trigeminal branches:
auriculotemporal of V3 (in front of ear and up)
zygomaticotemporal V2 (temple and up)
supraorbital V1 (forehead and above eyes)
supratrochlear branch of V1 (nose/midline forehead)

Question 6

what is the arterial supply of the scalp?

Answer 6

from external carotid a: occipital, posterior auricular, superficial temporal

from internal carotid a: supraorbital a, supratrochlear a.

Question 7

how does scalp drain?

Answer 7

vena comitantes of aa. 
emissary vv (drain through bones of skull to dural venous sinuses)

Question 8

why are scalp infections potentially dangerous?

Answer 8

scalp infection/bleeding can spread easily within the loose connective tissue layer (layer 4); can spread within the eyelids and dorsum of the nose and cause “ecchymosis” (extravasation of blood under skin).

Question 9

how are facial expression muscles innervated?

Answer 9

SVE portion of facial n.

- all are derived from pharyngeal arch 2

Question 10

orbicularis oculi

Answer 10

muscles associated with eyes/eyebrows
- orbital part: surrounds orbit and forcefully closes eye
palpebral portion: within eyelid to gently close eye
lacrimal portion: within medial corner of eye, helps with lacrimal fluid drainage

Question 11

corrugator supercilli

Answer 11

draws eyebrows down and in - worried look

Question 12

occipitofrontalis

Answer 12

muscles associated with scalp and forehead

• frontal belly: elevates eyebrows, wrinkles skin of forehead
• occipital belly- retract scalp, helps with “suprised” expression

Question 13

orbicularis oris

Answer 13

closes lips/mouth

Question 14

buccinator

Answer 14

keeps cheeks in contact with gums to food does not accumulate in vestibule of mouthg

Question 15

levator labii superioris

Answer 15

elevates upper lip

Question 16

levator anguli oris

Answer 16

elevates upper lip; widens mouth

Question 17

zygomaticus major

Answer 17

elevates upper lip “main smile muscle”

Question 18

zygomaticus minor

Answer 18

elevates upper lip

Question 19

risorius

Answer 19

stretches lips laterally into wide muscle

Question 20

levator labii superioris alaeque nasi

Answer 20

elevates upper lip and flares nostrils

Question 21

depressor anguli oris

Answer 21

depresses lower lip; frown

Question 22

depressor labii inferioris

Answer 22

depresses lower lip; pout/frown

Question 23

mentalis

Answer 23

protrudes lower lip: pout mm.

Question 24

procerus

Answer 24

wrinkles skin over dorsum of nose

Question 25

nasalis

Answer 25

flares nostrils

Question 26

platysma

Answer 26

depresses mandible, tenses skin of lower face and neck

Question 27

where does facial nerve travel?

Answer 27

exits brainstem and enters internal acoustic meatus. courses laterally between cochlea and semicircular canals and along posterior wall of middle ear, exits facial canal via stylomastoid foramen

Question 28

branches of facial nerve?

Answer 28

1. posterior auricular n. - supplies occipital belly of occipitofrontalis 2. digastric n. 3. stylohyoid n. 4. temporofacial trunk: - temporal branch (above eye), - zygomatic branch (side of eye/upper cheek) - buccal branch (to nose/mouth) 5. cervicofacial trunk: - buccal branches (transversely across face) - marginal mandibular branches (lower mandible border) - cervical branch (to platysma )

Question 29

Bell's Palsy

Answer 29

= facial n. paralysis - many cases are idiopathic; although linked to herpes virus, trauma or lesion along course of nerve - results in paralysis of facial expression - facial asymmetry and drooping - drooping of lower eyelid causes drainage of tears and ulceration of eye - paralysis of orbicularis oris causes dribbling of saliva from mouth - loss of buccinator = food accumulation within cheek and teeth - impaired speech

Question 30

What does V1 supply?

Answer 30

opthalmic nerve - skin of forehead, upper eyelid, nose - branches: supratrochlear n. supraorbital n, lacrimal n, infratrochlear n, external nasal n.

Question 31

What does V2 supply?

Answer 31

Maxillary n. - provides skin of temporal region, upper cheek and lip, lower eye lid, ala of nose Branches: zygomaticotemporal, zygomaticofacial, infraorbital n.

Question 32

what does V3 supply?

Answer 32

mandibular nerve - lower cheek, lower lip, chin - provides: auriculotemporal n, buccal n, mental n.

Question 33

trigeminal neuralgia

Answer 33

a neurological condition characterized by episodes of brief, intense facial pain over an area of CN V distribution. - cause believed to be demyleination of axons within the sensory root of CNV. some cases can be due to compression by the superior cerebellar a. - divisions affected: V2>V3>V1

Question 34

nerve block administration?

Answer 34

- infraorbital n: injected around infraorbital foramen - mental n: injected around the mental foramen on chin - buccal n: injected via the oral vestibule just posterior to the 3rd mandibular molar

Question 35

hepres zoster

Answer 35

often affects the trigeminal ganglion - due to reactivation of previous infection of dorsal root or sensory ganglion by varicella zoster virus - rash confined to one dermatome - most often affects V1 and can lead to scarring/ulceration of cornea

Question 36

facial artery?

Answer 36

1. facial artery: branches from external carotid, through submandibular gland, arches over mandible just anterior to masseter to enter face. takes tortuous course along angle of mouth to lateral side of nose/medial eye angle (gives off: inferior and superior lalbial branches, lateral nasal and angular a.)

Question 37

superficial temporal artery?

Answer 37

terminal brnch of external carotid a. | - gives off transverse facial a, frontal branches and parietal branches.

Question 38

maxillary a?

Answer 38

branch off of external carotid a. | - gives infraorbital a, buccal a, and mental a.

Question 39

opthalmic a.

Answer 39

``` branch of internal carotid a. - gives off: supraorbital supratrochlear middle palpebral lacrimal dorsal nasal a. ```

Question 40

retromandibular vein

Answer 40

formed from union of superficial temporal and maxillary vv. - divides ant/post division - anterior division merges with facial v. - posterior division merges with posterior auricular v. to form the external jugular v.

Question 41

facial v.

Answer 41

begins at medial corner of eye as angular v. - joins anterior division of retromandibular v. to make common facial v. which then drains to IJV - communicates with deeper plexuses: with pterygoid plexus via deep facial v, with cavernous sinus via opthalmic vv.

Question 42

infection from face

Answer 42

the central face area is a "danger area" for infection to travel into the skull or deep face b/c the facial v. anastamoses with pterygoid plexus and cavernous sinus

Question 43

lymphatic drainage

Answer 43

- lymph drains to submental, submandibular, parotid lymph nodes - all ultimately flow to deep cervical lymph nodes along internal jugular v.

Question 44

where does parotid duct exist?

Answer 44

- leaves anterior border of gland and crosses the masseter muscle - pierces buccinator muscle and mucosa of cheek to enter the oral cavity opposite the 2nd upper molar tooth - abcesses or infections of dental origin may spread to the parotid gland via the parotid duct

Question 45

what are important structures embedded within the parotid gland?

Answer 45

1. facial n. 2. retromandibular v. 3. external carotid a. * during parotidectomy these structures must be isolated and protected in order to preent damage.

Question 46

what are chief complaints of problems with the parotid gland?

Answer 46

eyes dry and red dry mouth eyes are droopy

Question 47

Parasympathetic innervation of parotid gland?

Answer 47

Preganglionic: glossopharyngeal nerve with cell bodies located in salivatory nucleus in brain stem - CN IX exits at jugular foramen and gives a tympanic branch, the tympanic n. then enters the middle ear via tympanic canaliculuous. Travels through the middle ear and transforms into lesser petrosal n. Lesser petrosal n. - Lesser petrosal n. in the middle cranial fossa exits via the foramen ovale, once in the infratempora fossa it synapses in otic ganglion. Postganglionic: Cell bodies are located in otic ganglion. Postganglionic fibers travel with auriculotemporal branch of V3 Function: stimulates grand secretion from parotid gland

Question 48

sympathetic innervation to parotid gland

Answer 48

preganglionic cell bodies located in spinal cord at levels T1-4 Postganglionic cell bodies in superior cervical symp. ganglion - postganglionic fibers travel with external carotid n. to parotid tissue function: vasomotor: alters type of secretion

Question 49

Parotiditis

Answer 49

inflammation of the parotid gland - painful due to stretching of parotid sheath - pain can be carried via V3 and great auricular n. - often pain will "refer" to auricle, TMJ and external acoustic meatus

Question 50

sialolith

Answer 50

calcified concretion that can sometimes form in the parotid gland if it passes into the parotid duct the duct can become blocked and it is quite painful