Clinical anatomy of the face Flashcards
What is the name of the skeleton of the head?
cranium
What are the 2 parts of the cranium?
Neurocranium and viscerocranium
What is the neurocranium?
bony covering of the brain and meninges
What disease causes inflammation of the meninges?
meningitis
What is the name of the roof of the neurocranium?
Calvaria
What is the name of the floor of the neurocranium?
cranial base
How many bones make up the neurocranium?
8 bones - frontal, parietal (2), temporal (2), occipital, ethmoid, sphenoid
What is the viscerocranium?
facial skeleton
How many bones make up the viscerocranium?
14 bones
Which cranial bones are pneumatised?
temporal, frontal, ethmoid, sphenoid, maxillary bones
What does it mean if a bone is pneumatised?
it contains air within the bone
Which bones are pneumatised in the form of containing paranasal sinuses?
frontal, ethmoid, sphenoid and maxillary bones
How are the temporal bones pneumatised?
contain mastoid air cells
Where is the mastoid process located?
posterior to ear
Which bones forms the crash-impact barrier of the face?
zygomatic bone
What are the names of the cranial sutures?
coronal (between frontal and parietal), sagittal (between parietal), lambdoid suture (between occipital and parietal)
What is the name of the thin projection of bone that is part of the temporal bone?
styloid process
Function of styloid process
anchoring site for muscles and ligaments
What is the thinnest bone of the viscerocranium?
lacrimal bone
What is the name of the ear canal?
external auditory meatus
What is the weakest point of the cranium?
pterion
Why is the pterion the weakest point of the cranium?
because it is where the frontal, sphenoid, temporal and parietal bones all meet
Why can trauma to the pterion be dangerous?
can cause the rupture of middle meningeal artery (and vein) which leads to an extra-dural haemorrhage
What is the name of the delay in symptoms during an extra-dural haemorrhage?
lucid interval
Why is there a lucid interval after an extra-dural haemorrhage?
takes time for blood to gather and cause the dura to separate from the skull
What percentage of non-verbal communication is provided by facial expression?
80-90%
What are the boundaries for the anterior aspect of the head?
from forehead to chin and from ear to ear
What does the the structure of our face depend on?
the underlying skeleton (viscerocranium)
The growth of the facial skeleton takes longer than the development of what features?
orbit, nasal cavity, paranasal sinuses, teeth
What is the importance of dividing the neck into triangles/regions?
for identifying lumps and bumps, and understanding where cancer may have spread (e.g. oral squamous cell carcinoma can spread to neck)
How may the number of lymph nodes and the distance cancer has spread affect the prognosis?
the more lymph nodes affected and the further the spread indicates a worse prognosis
What is the name of the area between the eyebrows and superior to the nose?
glabella
What is the name of the brow ridge (raised bone above superior margin of orbit)?
supraciliary arch
What is the name of the groove located superior to the upper eyelid and inferior to supraciliary arch?
suprapalpebral sulcus
Name of skin fold of the upper eyelid that covers the inner corner of the eye
epicanthal fold
Name of the groove located inferior to lower eyelid
infrapalpebral sulcus
Name of the region between the root and apex of the nose
dorsum of nose
Name of the lower lateral margin of the external nose (wing of nose)
ala of nose
Name of the rounded tip of the nose
apex of nose
Name of nostrils
nares
Name of the part of the nasal cavity that divides the left and right nares
nasal septum
Name of the central vertical groove between the nose and upper lip
philtrum
Name of the groove that extends from the corners of the nose to the corners of the mouth
nasolabial sulcus
Name of the protuberance at the centre of upper lip
tubercle of upper lip
Name of the opening of the mouth
oral fissure
Name of the corners of the mouth
labial commissure
Name of the line around the lips where labial mucosa transitions into skin
vermillion border
Name of the indentation that separates the lower lip from the chin
mentolabial sulcus
Name of the projection of the anterior, central area of the mandible
mental protuberance
How many spinal nerves exist?
31 pairs
How many spinal nerves have their roots in each portion of the vertebral column?
8 from cervical, 12 from thoracic, 5 from lumbar, 5 from sacral, 1 from coccygeal
How many cranial nerves exist?
12 pairs
Where do cranial nerves arise from?
brain and brainstem
What are the 12 cranial nerves?
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal
Function of olfactory nerve
sense of smell (sensation to nasal mucosa)
Function of optic nerve
vision (sensation to retina)
Function of oculomotor nerve
motor function to extraocular muscles
Function of trochlear nerve
motor innervation to superior oblique (extraocular) muscle
Function of trigeminal nerve
sensation to the face and anterior 2/3 of tongue. Motor innervation of muscles of mastication
Which trigeminal branches supply sensory innervation to the face?
ophthalmic, maxillary, mandibular
Which branch of the trigeminal nerve provides motor innervation to the muscles of mastication?
mandibular
Function of abducens nerve
motor innervation to lateral rectus muscle (extraocular)
Function of the facial nerve
motor innervation to muscles of facial expression; taste (special sensory); salivary secretions from sublingual and submandibular glands (parasympathetic fibres); and sensation to ear, nasal cavity, soft palate and anterior 2/3 of tongue
Function of vestibulocochlear nerve
hearing and balance (sensory nerve)
Function of glossopharyngeal nerve
motor innervation of pharyngeal constrictors. Taste (sensory). sensation to posterior 1/3 of tongue and epiglottis
Function of vagus nerve
Motor, sensory and parasympathetic innervation to thoracic an abdominal viscera (e.g. gut motility). Motor innervation to muscles of larynx and pharynx
Function of accessory nerve
motor innervation to trapezius and sternocleidomastoid (2 neck muscles)
Function of hypoglossal nerve
Motor function for most muscles of the tongue (except 1)
What are the branches of the trigeminal nerve?
ophthalmic nerve (Va), maxillary nerve (Vb), mandibular nerve (Vc)
Function of the trigeminal nerve
sensory innervation to the face and motor innervations of muscles of mastication
Function of the ophthalmic division of the trigeminal nerve (CN Va)
sensory innervation to the forehead, scalp, paranasal sinuses, upper eyelid and conjunctiva, cornea and dorsum of nose
Function of the maxillary division of the trigeminal nerve (CN Vb)
sensory innervation to the lower eyelid and conjunctiva, cheeks, maxillary sinus, nasal cavity, lateral nose, upper lip/teeth/gingiva, superior palate
Function of the mandibular division of the trigeminal nerve (CN Vc)
Sensory innervation of floor of oral cavity, external ear, lower lip/teeth/gingiva, chin, anterior 2/3 of tongue. Motor innervation of muscles of mastication
Which nerve supplies taste on the tongue?
branch of the facial nerve CN VII called chorda tympani
What are the names of viruses that can lie dormant in the ganglia and travel down nerve fibres of the trigeminal nerve branches?
Herpes simplex virus (HSV) and Varicella zoster virus (VZV)
Which branches of the trigeminal nerve may be affected by HSV?
maxillary or mandibular (cold sores form around corners of mouth)
What is the difference between type 1 and type 2 HSV?
type 1 common in mouth whereas type 2 is common in genitalia
What are the muscles of mastication?
temporalis, masseter, medial and lateral pterygoids
Function of the masseter
elevates the mandible and closes the mouth
Where does the masseter originate?
zygomatic arch
Where does the masseter insert itself?
mandibular angle
Function of the temporalis
elevates mandible (closes mouth) and retracts the mandible
Where does the temporalis originate?
frontal/parietal bones
Where does the temporalis insert itself?
coronoid process of mandible
Function of the medial pterygoid
elevates the mandible (closing mouth)
Function of the lateral pterygoid
bilateral contraction - protrusion of mandible, unilateral contraction - moves mandible to opposite side
How can you test the muscles of mastication clinically?
As patient to clench and relax while palpating the masseter and temporalis, looking for symmetry
How many muscles are there in the face?
43
How are the muscles of the face arranged?
arranged around the orifices (mouth, nose, eyes, ears
What are the muscles of the face attached to?
bone or fascia, and then attached to the skin
Which nerve supplies the muscles of facial expression?
facial nerve (CN VII)
What actions can you produce in the upper lip and lower lip?
elevate, retract, evert (e.g. pout/push forward)
Which muscle of facial expression is unpaired and forms a ring around the mouth?
orbicularis oris
Where does orbicularis oris originate from?
maxilla and cheek muscles
Where does orbicularis oris insert into?
the skin and mucous membrane of the lips
Which nerve supplies orbicularis oris?
buccal branch of the facial nerve (CN VII)
Where does the buccinator originate?
Maxilla and mandible
Where does the buccinator insert itself?
blends with orbicularis oris and skin of the lip (at the modiolus - corner of mouth)
Function of buccinator
pulls cheeks inward, pushing food and fluid into centre of oral cavity. Puffs out cheeks
Which nerve supplies the buccinator?
buccal branch of the facial nerve
What are the muscles of the orbital (eye) opening?
palpebral part and orbital part of orbicularis oculi
Where is the palpebral part of the orbicularis oculi located?
In eyelids
Function of the palpebral part of orbicularis oculi
soft closure of the eyes including blinking
Function of the orbital part of orbicularis oculi
Strong closure of the eyes
What are the names of the muscles of the ear?
auricularis superior, auricularis anterior and auricularis posterior muscles
Functions of the auricular muscles
Vestigial - no useful function in humans
What type of secretion is produced by the parotid duct?
Serous
Where does the parotid duct enter the oral cavity?
Opposite the second upper molars (17, 27)
Where is the parotid gland located?
anterior and slightly inferior to ear
What 3 major structures pass through the parotid gland from deep to superficial?
external carotid artery, retromandibular vein, facial nerve
How is the retromandibular vein formed?
by the superficial temporal and maxillary veins uniting
What are the 2 terminal branches of the ECA that pass through the parotid gland?
maxillary and superficial temporal arteries
What is the inciting agent for mumps?
paramyxovirus
Symptoms of mumps
swelling of parotid gland and lymph nodes (including those inside gland - hamster appearance), painful, possible weakness of face
Why may mumps be painful?
the fascia surrounding the parotid gland is stretched
Why may mumps cause weakness of the face?
the swollen parotid gland can press on branches of the facial nerve
Possible complications that can arise from mumps/paramyxovirus
deafness, infertility, meningitis
How is mumps treated?
it usually clears itself. Only supportive treatments like analgesia and bed rest are used.
What is facial palsy/paralysis?
weakness and loss of function of the muscles of facial expression
What is the name for the surgical removal of the parotid gland?
parotidectomy
What is the most common cranial neuropathy?
Bell’s palsy
Symptoms of Bell’s palsy
facial paralysis on one side (left or right)
When is Bell’s palsy diagnosed?
once other causes have been excluded (e.g. stroke) and no specific cause can be identified
Which diseases can cause Bell’s palsy?
Herpes simplex virus, herpes zoster, (HIV, TB, cold)
What are the 2 treatments for Bell’s palsy?
Prednisolone (steroid - reduces inflammation), Acyclovir (helps with viral infection)
Cause of Bell’s palsy
swelling of the facial nerve as it passes through the stylomastoid foramen
What percentage of all head and neck tumours are found in the parotid gland?
3%
What percentage of tumours of the salivary glands are found in the parotid gland?
75-85%
What percentage of parotid tumours are benign?
70-80%
What are the 5 main branches of the facial nerve (CN VII)?
Temporal, zygomatic, buccal, marginal mandibular, cervical
Which muscles of facial expression does the temporal branch of the facial nerve innervate?
frontalis, orbicularis oculi (upper part), corrugator supercilii
Function of the corrugator supercilii muscles
draws eyebrows together to produced frowning
Which muscles of facial expression are innervated by the zygomatic branch of the facial nerve?
orbicularis oculi (lower part)
Which muscles of facial expression are innervated by the buccal branch of the facial nerve?
orbicularis oris (upper part), buccinator, zygomaticus muscles (zygomatic bone -> angle of mouth)
Which muscles of facial expression are innervated by the marginal mandibular branch of the facial nerve?
mentalis muscle, depressor muscles, orbicularis oris (lower part)
Which muscle is innervated by the cervical branch of the facial nerve?
platysma
Which structures must surgeons be careful not to damage during a parotidectomy?
facial nerve (CN VII)
What are the 2 types of parotidectomy?
anterograde and retrograde
What is an anterograde parotidectomy?
identifying the main trunk of facial nerve and tracing out to finer branches
What is a retrograde parotidectomy?
identifying the smaller branches of the facial nerve and tracing back towards the parotid gland
Why are electrodes placed on the face of the patient during a parotidectomy?
Surgeons need to identify the facial nerve first. They do so by buzzing the suspected structures and seeing if impulses of nerves/muscles are picked up by the electrodes.
What is the name of the incision made during a parotidectomy?
modified blair incision
Where does a modified blair incision cut?
pre-auricular incision (infront ear to below ear), over the mastoid process and into skin crease of the neck
Why is the incision during a parotidectomy made into a neck crease?
better healing and scar will be less visible
What is the name of the orange, iodine, antiseptic solution used in surgeries?
betadine
Which nerve can be used in a nerve graft if the facial nerve is damaged?
great auricular nerve (only innervates small area of skin on mandible)
Where does the great auricular nerve originate?
C2-3
Function of sternocleidomastoid
unilateral contraction moves neck to opposite side whereas bilateral contraction flexes the neck
Function of the external jugular vein
drains superficial structures of the head
Where does the external jugular vein travel along?
just inferior to the parotid gland, EJV travels obliquely superficial to the sternocleidomastoid towards the clavicle and drains into the subclavian vein.
Which veins unite to form the external jugular vein?
posterior auricular vein and posterior division of the retromandibular vein
Before the facial nerve branches into 5, it bifurcates into which 2 main branches?
Cervicofacial and temporofacial
What is the name of the procedure used to bring the face back to life after impairment of the facial nerve?
facial reanimation
What needs to be taken into consideration before a facial reanimation is deemed appropriate?
level of injury (skull/brainstem or further out in branches across face) and the duration of paralysis
What are the 3 types of facial reanimation?
immediate/early reconstruction (dynamic), intermediate reconstruction (dynamic), late reconstruction (static)
After what time frame is dynamic facial reanimation not possible?
> 12 months as nerves and motor end plates die and muscle atrophies
Function of dynamic facial reanimation
to bring back movement and function of the face (muscles of facial expression)
Purpose of static facial reanimation
cosmetic purposes - to make the face more symmetrical and reduce sagging
Which nerves undergo anastomosis during dynamic facial reanimation?
hypoglossal (CNXII) and facial (CNVII)
Are the muscles of the tongue still functional following facial-hypoglossal anastomosis?
Yes - part of hypoglossal nerve is still intact
Side effects observed after dynamic facial reanimation
patients had twitching of the face while eating/drinking
How were the functions of the tongue and muscles of facial expression isolated following dynamic facial reanimation?
craniofacial physiotherapy and botulinum toxin type B injections
How is static facial reanimation conducted?
a trouser graft is made of fascia lata and inserted under the skin from the corner of the mouth to the hairline
What is the fascia lata?
fibrous avascular band that runs along the lateral aspect of the thigh and plays a very minor role in hip movement and knee stabilisation
What is the name of the thickened aspect of the fascia lata?
iliotibial tract
How is the fascia lata removed from the thigh?
using endoscope - instead of making large s-shaped incision
What is the advantage of using an endoscope instead of s incision to remove the fascia lata?
a small incision is required - better healing, less scarring, lower infection risk
Why is the fascia lata graft called a ‘trouser’ graft?
the fascia lata is split into 2 with each end of the split attaching onto the upper and lower lips.
Where is the fascia lata attached to in the face?
zygomatic bone and modiolus (corner of mouth - upper and lower lip)
