ALL THE THINGS Flashcards
How many territories is the face divided into?
8
What are the territories of the face?
mental (chin) oral (mouth) buccal (cheek) temporal zygomatic orbital infraorbital supraorbital
How many facial muscles are there and what do they allow us to express?
43 muscles that express universal emotions
What are the two trochlear regions of the face?
Supra and Infratrochlear regions
What is the function of the trochlear region of the face?
Supra/infratrochlear regions act as a pulley system for the superior oblique muscle. Important area for rhino surgeries
What are the important facial muscles?
Platysma Orbicularis oculi Orbicularis oris Zygomaticus major Buccinator Occipital Frontalis
What are the 3 parts of the orbicularis oculi?
Orbital part
Palpebral part
Lacrimal part
What is the orbital part of the orbicularis oculi responsible for?
for winking
What is the palpebral part of the orbicularis oculi responsible for?
responsible for blinking and wetting the cornea
What is the lacrimal part of the orbicularis oculi responsible for?
compresses lacrimal sac to release tears
What is the orbicularis oris responsible for?
purses lips, manipulates food
Why is the Zygomaticus major muscle important?
landmark for vessels running underneath
What is the buccinator muscle responsible for?
important for swallowing
How are the fibers of the buccinator muscle oriented?
at right angles to the plane of the face
important area for face lifts
What is the occipital frontalis associated with?
the galea aponeurotica
What is the galea aponeurotica?
a broad aponeurosis that extends over the head to the occipitalis major
What does the galea aponeurotica form?
one of the layers of the scalp
Motor functions of the facial nerve involve what?
UMNs and LMNs
What controls the muscles of mastication?
motor branch of CN V3
UMNs of the CN VII are located in what region of the motor homunculus?
facial region
LMNs are in the facial motor nucleus in the brainstem on what side?
in the brainstem on the opposite side
The facial motor nucleus activates LMNs to input what muscles?
muscles of facial expression
The muscles of mastication rare regulated by what nucleus?
the motor nucleus of V
Which specific muscles are innervated by the facial motor nucleus axons?
Stylohyoid muscle
Posterior belly digastric
muscles of facial expression
Stapedius muscle
Which specific muscles are innervated by the motor nucleus of V axons?
masseter
medial/lateral pterygoid muscles
temporalis anterior belly of digastric
tensor tympani
tensor palati
mylohyoid
Which muscle is involved in smiling?
Risorius
How many peripheral branches of CN VII are there?
5
What are the peripheral branches of CN VII on the face?
temporal zygomatic buccal mandibular cervical
What do the peripheral branches of CN VII innervate?
facial muscles
Where do ALL the peripheral branches of CN VII pass through?
the parotid gland
Bell’s palsy is a paralysis of what?
of the peripheral branches of the facial nerve
What is typically implicated as a cause of Bell’s Palsy?
Lyme disease
What causes the paralysis seen in Bell’s Palsy?
LMN lesion
What muscles are affected in a person with Bell’s Palsy? What are the symptoms associated?
orbicularis oris - drooling
buccinator - disrupted swallowing, speech
orbicularis oculi - tears cannot wet eyeball leading to ulceration
What can sometimes remedy Bell’s Palsy?
an end to end nerve anastomosis can remedy the symptoms
How does CN VII get to the stapedius in order to innervate it?
passes through the facial canal
What does the stapedius muscle do?
dampens sound
Where do the axons of the facial motor nucleus exit to innervate the stylohyoid and posterior belly of the digastric muscle?
exit the skull at the stylomastoid foramen
What are the locations of possible lesions of the facial nerve?
near the stylomastoid foramen
in the facial canal
What is the result of a lesion near the stylomastoid foramen?
Bell’s Palsy
What is the result of a lesion in the facial canal?
Bell’s palsy and hyperacusis
What is hyperacusis?
exaggerated sound
A lesion or neuroman at the internal acoustic (auditory) meatus will result in what?
Bell’s palsy, hyperacusis, and problems with hearing and balance
What group of glands is the Parotid gland apart of?
one of the 3 salivary glands
What is another name for the parotid duct?
Stensen’s duct
Describe how the parotid duct is positioned
crosses the face, wraps medial to the masseter muscle, pierces the buccinator muscle, and enters the mouth adjacent to 2nd maxillary molar tooth
What are some common problems associated with the parotid gland?
Parotitis (mumps)
Pleomorphic (mixed) adenomas
Parotitis is the result of what?
highly contagious viral infection of the parotid gland that is now controlled by vaccine
What does a parotitis affected individual present with commonly?
swelling and pain
Parotitis is common in _____ without complications, but is serious in ____ .
common in young without complications
serious in adults
In adults, what can the virus associated with parotitis cause?
orchitis (swelling of the testicles)
infertility (rarely)
increased chances for abortion
What are Pleomorphic adenomas?
mixed, benign tumors
What is clinically significant about the fact that the branches of CN VII go through the parotid gland in ONE plane?
the gland above and below can be surgically removed without damaging the nerve
Where are the pre-ganglionic parasympathetic neurons of the parotid gland located?
in the inferior salivatory nucleus
Where do the pre-ganglionic parasympathetic neurons of the parotid gland exit and where do they go after that?
exit in CN IX
take a circuitous route to the otic ganglion where they synapse on post ganglionic neurons
After synapsing, where do the postganglionic parasympathetic axons of the parotid go?
they enter the auriculo-temporal branch of V3 to the gland
What would happen to the parasympathetic axons if I removed the parotid gland?
the axons will be severed, but they will regenerate and innervate sweat glands
What is the result of the parasympathetic axons regenerating to innervate sweat glands upon removal of the parotid gland?
Frey’s Syndrome
What is Frey’s syndrome?
when the paraysmpathetic system is activated by eating, the sweat glands are activated
How is the parotid gland innvervated sympathetically?
Preganglionic ganglionic sympathetic neurons from Lamina 7, T1-2, travel up synapse in the superior cervical ganglion, post ganglionic neurons follow blood vessels to the gland
What is the result of sympathetic innervation of the parotid gland?
saliva is NOT released, but it’s viscosity is regulated
Are the muscles of mastication activated individually?
Nope
Mastication results from the activation of what?
a dedicated UMN circuit
When the UMN circuit is activated, what happens?
the axons at the circuit descend the cortico-bulbar tract
After the axons descend the cortico-bulbar tract, what is the next step to activate the muscles of mastication?
as they descend the tract, the axons synapse on group of LMNs in the motor nucleus of V
Once the group of LMNs in the motor nucleus of V are synapsed on, what happens?
the axons of the LMNs produce a coordinated activation of the muscles resulting in mastication
Afferent innervation of the orofacial region involve the 3 division of which nerve? Name the divisions as well.
CN V - Trigeminal nerve
V1 - Opthalmic
V2 - Maxillary
V3 - Mandibular
What is the Tragal Line?
Dividing line between the cranial system and the spinal system.
V3 branch sensation stops at the Tragal Line
Each branch of CN V occupies what?
a specific territory anterior to the tragal line
Each branch of CN V innervates its territory —
Exclusively!
THERE IS NO DERMATOME OVERLAP AS IN SPINAL NERVES!
The terminal cutaneous branches of CN V include what?
V1 - supraorbital, supratrochlear, infratrochlear, lacrimal
V2 - infraorbital, small zygomaticofacial, zygomaticotemporal
V3 - mental, buccal, auriculo-temporal
CN V conveys sensations from where else?
the teeth, gums, meninges, cerebral blood vessels, and the cornea all via the internal branches of CN V
The majority of the sensory innervation of the face is carried out via which terminal cutaneous branches of CN V?
V1 - Supraorbital nerve
V2 - Infraorbital nerve
V3 - Mental nerve
A unique feature of CN V is that there is no overlap in its peripheral branches. What does this allow us to do?
each branch can be tested and anesthetized separately
procedures can then be performed under local anesthesia
What pathology is associated specifically with CN V?
Trigeminal neuralgia (Tic Doloroux)
What is trigeminal neuralgia?
horrendous, debilitating pain that usually involves the infraorbital nerve
How is the pharmacology of CN V unique?
drugs effective in alleviating nervous disorders in other regions of the body are not as effective in dealing with CN V disorders
How does CN V refer pain to skin to skin areas of the forehead and eye?
afferents of V1 from cerebral blood vessels refer the pain to skin areas that are a branch of the same nerve
All of the blood to the head region comes from what?
the external carotid
What provides blood to the brain?
the internal carotid artery
What are the two divisions of the carotid artery?
internal and external
Does the internal carotid artery have external branches?
Nope
What is the primary artery of the face?
the facial branch of the external carotid artery
What is unique about the facial branch of the external carotid artery?
it takes a tortuous course near the mouth to avoid stretching when the mouth is opened
What supplies circulation to the scalp?
the superior temporal artery and its branches
Why do the branches of the superior temporal artery bleed copiously?
they are not end arteries, so blood will emerge from both cut ends
What does the facial vein begin as and where does it course?
begins as the angular vein and courses to the lower border of the mandible
Where does the facial vein receive tributaries from?
lips (labial)
palpebral (eyelids)
external nasal areas
Below the mandible, angular vein becomes what?
the common facial vein
The common facial vein joins what vein and terminates at what vein?
joins the retromandibular vein and terminates in the internal jugular vein
Since the facial vein doesn’t have valves, what makes it a potential danger area?
its connections to opthalmic veins can convey an embolism to the cavernous sinuses
Since the facial vein has no valves, what determines flow?
posture
The facial skull consists of how many bones?
14
Where are the most common fractures of the facial skull seen?
Nasal bone - readily repaired
Mandible
More serious facial skull fractures are classified according to what?
Le Fort classification
Describe a Le Fort type I fracture
horizontal across maxillae
Describe a Le Fort type II fracture
through maxillary sinuses, infraorbital foramina, bones of medial orbit and then across the bridge of the nose
Entire central part of the face becomes separated from the skull
Describe a Le Fort type III fracture
horizontal through superior orbital fissure of the orbit
Causes separation from the skull
Why are Le Fort types II and III the most serious?
they involve the orbit and its contents
What is the clinical benefit of the Le Fort fracture lines?
the skull can be disarticulated along the lines to correct facial anomalies
applicable to Crouzon’s Syndrome
What does the scalp offer the skull?
considerable protection from injury
How many layers make up the SCALP?
5 layers
What are the layers of the SCALP?
Skin
Connective tissue
Aponeurosis (galea aponeurotica)
Loos connective tissue
Periosteum
Describe the connective tissue layer of the SCALP and what it contains
dense and contains the extensive network of superficial blood vessels and nerves
What does the aponeurosis layer of the SCALP cover?
the temporalis, frontalis, occipitalis muscles.
is firm and difficult to penetrate
Describe the loose connective tissue layer of the SCALP and why it is considered a danger area
forms a potential space under the galea aponeurotica that is easily filled with blood
blood can extravasate into the peri orbital region resulting in ecchymosis (Raccoon Eyes)
Infections can move through the same way and gain access to the meninges and brain via emissary veins
What are the blood vessels and arteries of the scalp called?
the Superficial Temporal Arteries
