4: Skull, Face & Scalp Flashcards
where are all preganglionic sympathetics for the head located
lateral horn of T1
where are all postganglionic sympathetics for the head located
superior cervical ganglion
what nerves serve as the parasympathetics for the head
CN III
CN VII
CN IX
why are lymphatics important
that’s where infections spread
neurocranium
cranial bones to protect the brain
8 bones
viscerocranium
facial bones to protect airway
15 bones
pterion
point where bones can readily break
blood from the middle meningeal artery can be a problem here
what is the orientation of the foramen on the face
vertical; important for the trigeminal branches (V1, V2, V3)
calvaria
skull cap
bones of the neurocranium
frontal ethmoidal sphenoidal occipital temporal (2) parietal (2)
bones of the viscerocranium
ethmoid vomer mandible maxilla (2) inferior nasal concha (turbinate) (2) zygomatic (2) palatine (2) nasal (2) lacrimal (2)
features of maxilla & mandible
alveolar processes mental foramen (mandible) infraorbital foramina (maxilla) coronoid process condyloid (condylar) process (TMJ) head, neck, ramus, body & angle mandibular notch & foramen mylohyoid groove mental spines or genial tubercles (superior & inferior)
boundaries of orbit
frontal bone=roof
zygomatic bone=lateral wall
maxilla bone=floor & part of medial wall
lacrimal & ethmoid bones=rest of medial wall
sphenoid bone=posterior wall
features of the orbit
supraorbital foramen/notch: in superciliary arch
optic canal (foramen): in median wall
superior orbital fissure: in medial wall
inferior orbital fissure: in floor
lacrimal groove (nasolacrimal canal): communicates with nasal cavity
boundaries of the nasal cavity
nasal bones + frontal sinus + ethmoid + sphenoid sinus = roof
maxillary bones = floor & lateral wall
palatine horizontal plate = floor
vomer & perpendicular plate of ethmoid bones = medial wall
nasal septum = medial wall
features of the nasal cavity
nasal conchae = projections from lateral wall
superior nasal conchae = ethmoid bone
middle nasal conchae = ethmoid bone
inferior nasal conchae = separate bones
conchae = turbinates
most of these features have a nasal mucosal membrane
what are the 3 cranial fossa
anterior cranial fossa (frontal lobes)
middle cranial fossa (temporal lobes)
posterior cranial fossa (cerebellum & brainstem)
features of paranasal sinuses
4 pairs of paranasal sinuses
spaces within skull bones
make bones lighter
add resonance to voice
lined by mucosal membrane
continuous with nasal cavity
what are the paranasal sinuses
frontal sinuses (2)
ethmoid air cells (3-13)
sphenoid sinuses (2)
maxillary sinuses (2)
cribriform plate
olfactory n. (CN I)
optic canal
optic nerve (CN II), ophthalmic a.
superior orbital fissure
CN III, IV, VI, ophthalmic (CN V1)
foramen rotundum
maxillary n. (CN V2)
foramen ovale
mandibular n. (CN V3)
foramen spinosum
middle meningeal a.
foramen lacerum
nothing passes thru it
jugular foramen
IJV, CN IX, X & XI
internal acoustic foramen
CN VII & VIII
stylomastoid foramen
CN VII
hypoglossal canal
CN XII
foramen magnum
vertebral arteries, spinal cord, CN XI
carotid canal
internal carotid a. (enter skull here)
layers of the scalp
Skin Connective tissue Aponeurosis (epicranial aponeurosis) Loose Connective Tissue Pericranium
skin
thin (except occipital region)
many sweat and sebaceous glands and hair follicles
lots of arteries, veins, and lymphatic drainage
connective tissue
thick, vascularized subcutaneous layer
many cutaneous nerves
aponeurosis
strong tendinous sheet
covers calvaria
attachment for frontal and occipital bellies of occipitofrontalis m. and superior auricular m.
together = musculoaponeurotic epicranius
loose connective tissue
sponge-like layer
potential spaces that may distend with fluid upon injury/infection
allows free movement of scalp proper (1st 3 layers) over underlying calvaria
pericranium
dense layer of connective tissue
forms external periosteum of neurocranium and is firmly attached
parts of it are continuous with fibrous tissue in cranial sutures
scalp lacerations
in C layer
tend to bleed a lot bc well vascularized
can result in death
deep wounds into A layer gape, bc muscle is pulling aponeurotic sheet apart
clinical note: loose areolar tissue
danger space of scalp
infections spread easily here
infections travel into cranial cavity thru emissary veins to meninges
fluid can move anteriorly into eyelids & root of nose
occipitofrontalis m.
moves scalp back and forward
occipital m. + galea aponeurotica + frontalis m. (epicranial aponeurosis)
anterior auricularis m.
protract ear
superior auricularis m.
elevate ear
posterior auricularis m.
retract ear
frontalis m.
raises eyebrow (surprise)
corrugator supercilii m.
draws eyebrow in (frowning)
orbicularis oculi m.
closes eye (winking)
orbital and palpebral portions
origin of mm. of eye
either bone or connective tissue
termination of mm. of eye
always bone
procerus m.
wrinkles bridge of nose
nasalis m.
compresses & dilates nostril
levator labii superioris alaeque nasi m.
dilates nostril
orbicularis oris
closes mouth
levator labii superioris
elevates upper lip
zygomaticus major/minor
draws mouth up
depressor anguli oris
depresses angle of mouth
depressor labii inferioris
depresses lower lip
risorius
retracts corner of the mouth
mentalis
protrudes lower lip
buccinator
compresses cheek & assists with mastication
levator anguli oris
elevates angle of mouth
depressor labii inferioris
depresses lower lip
temporalis
elevates & retracts mandible
masseter
elevates & clenches mandible
medial pterygoid
elevates, protracts & rotates mandible
lateral pterygoid
protrudes & rotates mandible; opens mouth
trigeminal n. (CN V)
sensory to the face & scalp
cervical n. (C2-C3)
sensory to the back of the head, ears & jaw
facial n. (CN VII)
motor to the mm. of facial expression
mandibular n. (CN V3)
motor to mm. of mastication
V1 sensory branches
supraorbital n. - to central forehead
supratrochlear n. - to medial forehead
infratrochlear n. - to upper nose
external nasal n. - to lower nose
lacrimal n. - to lateral brow
V2 sensory branches
zygomaticotemporal n. - to temple
zygomaticofacial n. - to upper cheek
infraorbital n. - to maxilla & upper lip
V3 sensory branches
auriculotemporal n. - to ear & temple
buccal n. - to lower cheek
mental n. - to chin & lower lip
parotid gland
anterior/inferior to ear
calculus formation is assoc. w/chronic parotiditis (all 3 salivary glands) (stones can get caught in duct, VERY PAINFUL)
salivary fistulas (opening/communication to outside)
neoplasms (85-90% of mixed tumors involve parotid)
Frey’s Syndrome
facial n. (CN VII) passes thru gland and can be in danger during parotidectomy (damage can cause paralysis of facial mm. on affected side)
Frey’s Syndrome
gustatory sweating
following a procedure, nn. get parasympathetic layer on top of them when healing
instead of salivating, your face sweats a lot in the parotid area
weird af
nerve branches from parotid gland
pharyngeal arch 2 derivatives
nn. to posterior belly of digastric and stylohyoid mm.
posterior auricular n.
temporofacial branch
temporal branches
buccal branches
marginal mandibular branches
cervical branches
cervicofacial branch
“People To Zanzibar By Motor Car”
motor innervation of facial n. (CN VII)
temporal branches - superiorly to temples
zygomatic branches - inferiorly to arch
buccal branches - medially to buccinator m.
marginal mandibular branches - along inferior mandible
cervical branches - inferiorly to platysma m.
posterior auricular branches - posteriorly to lower ear
clinical note: facial n. (CN VII)
injury produces m. paralysis on affected side
n. may be inflamed at stylomastoid foramen
edema & compression of n. in facial canal
Bell’s Palsy: most common non-traumatic cause of facial paralysis (unilateral) (most resolve in 2-3 weeks, rarely permanent)
buccal fat pad
anterior to masseter m.
covers buccinator m.
protects parotid duct and buccal branch of CN VII
gives cheeks fuller appearance
buccal nn. of buccinator m.
buccal branch of facial n. - CN VII motor to buccinator m.;lateral to masseter m.
buccal branch of trigeminal n. - CN V3 sensory to buccal mucosa & skin of cheek (V3 ONLY PIERCES BUCCINATOR M. BUT DOES NOT SUPPLY IT)
superficial temporal a.
branch of external carotid a.
at superior margin of parotid gland, runs anterior to ear to temporal region
travels with auriculotemporal n.
superficial temporal v.
drains to retromandibular v.
runs anterior to ear to temporal region
travels with auriculotemporal n.
lose it once it dives under parotid gland
transverse facial a. & v.
branches of superficial temporal vessels
cross masseter m. btwn zygomatic arch & parotid duct
supply blood to upper cheek region
facial a. & v.
artery is tortuous & anterior to vein; branch of external carotid, superior to lingual artery
both cross mandible at ant. border of masseter m.
at angle of mouth
continue to medial angle of eye to angular a. & v.
IJV branches
angular v. facial v. superior thyroid v. retromandibular v. pterygoid plexus (deep temporal vv.)
deep venous plexus connects w/emissary vv.
EJV branches
anterior jugular v. occipital v. posterior auricular v. maxillary v. superficial temporal v. retromandibular v. pterygoid plexus (deep temporal vv.)
deep venous plexus connects w/emissary vv.
lymphatic drainage of head & neck
ipsilateral
medial to lateral (neck)
drains inferiorly & superficial to deep
ultimately to the right lymphatic duct or the thoracic duct
submental nodes
inf and post to the chin
drain from medial lower lip to the chin
ipsilateral
submandibular nodes
superficial to gland and inf to body of mandible
drain from medial corner of orbit, most external of nose, medial part of cheek, upper lip, lateral lower lip
preauricular & parotid nodes
ant to ear
drain most of eyelids, part of ext nose, lateral cheek
