A6 - the face Flashcards
how may bones make up the viscerocranium?
14
what is the common embryonic origin of the muscles of facial expression?
2nd pharyngeal arch
all the muscles of facial expressions are innervates by what?
facial nerve
where do the muscles of facial expression insert?
dermis of the skin
what is the muscle of the scalp?
occipitofrontalis
describe the occipitofrontalis
- consists of 2 bellies (frontal and occipital), joined in the middle by an aponeurosis
- the muscle moves the scalp on the skull, wrinkles the skin on the forehead and elevates the eyebrows
what are the 2 muscles of the eyelids?
orbicularis oculi and corrugator supercilii
what are the 2 parts of orbicularis oculi?
orbital and palpebral
what do the 2 different parts of orbicularis oculi do?
- orbital — wrinkles the eyelids and closes them tightly
- palpebral — closes the eyelids gently
what does corrugator supercilii do?
draws the eyelids medially forming wrinkles in the forehead
what are the 3 muscles of the nostrils?
nasalis, depressor septi nasi and procerus
label the 3 muscles of the nose
label the muscles that act on the lips
what is the muscle of the cheek and its function?
buccinator — required for blowing and sucking and is also used to keep the bolus of the food between the teeth when chewing
what is the muscle of the neck and its function?
= platysma
- depresses the mandible and the angle of the mouth and tenses the skin over the inferior face and neck
what innervates all the muscles of mastication?
the mandibular branch of the trigeminal nerve (V3)
what nerves exit at where the arrows are pointing? where do the nerves arise?
describe infraorbital and mental nerves
a - infraorbital nerve = terminal branch of the maxillary division of CN V
d - mental nerve = branch of inferior alveolar nerve which arises from the mandibular division of CN V
label the muscles A-H
what are the 5 layers of the scalp?
S — skin
C — connective tissue — a fibrofatty layer that attaches the skin to the underlying aponeurosis.
many arteries and vins form an anastomosing network in this layer
A — aponeurosis (of occipitofrontalis)
L — loose areolar connective tissue — connects the aponeurosis to the periosteum of the skull. it
contains important emissary veins that connect the superficial veins of the scalp with the
diploic veins of the skull with the dural venous sinuses
P — pericranium — the periosteum covering the bones of the skull
what are the muscles of mastication?
- masseter
- temporalis
- medial pterygoid
- lateral pterygoid
all the muscles of mastication insert into the ____ and act on the _____
- mandible
- temporomandibular joint
origin, insertion and action of temporalis
- O = temporal fossa
- I = coronoid process of mandible
- A = elevation and retraction of mandible
origin, insertion and action of masseter
- O = zygomatic arch
- I = lateral surface of ramus and angle of mandible
- A = elevation of mandible
origin, insertion and action of medial pterygoid
- O :
head 1 = medial aspect of lateral pterygoid plate
head 2 = tuberosity of maxilla - I = medial surface of ramus and angle of mandible
- A = laterally moves and protracts mandible
origin, insertion and action of lateral pterygoid
- O :
head 1 = infratemporal surface and crest of greater wing of sphenoid
head 2 = lateral surface of lateral pterygoid plate - I = neck of mandible
- A = laterally moves and protracts mandible
(protrusion of mandible if both sides contracting, lateral deviation of mandible if only one side contracting)
what other muscles assist in mastication in depressing the jaw?
digastric, geniohyoid and mylohyoid
describe the parotid gland
- a bilateral salivary gland
- the largest of 3 salivary glands
where is the parotid gland?
wedged between the ramus of the mandible anteriorly and the mastoid process and sternocleidomastoid posteriorly
what does the parotid gland extend superficially over?
the masseter muscle
what encapsulates the parotid gland?
parotid sheath
why is there fatty tissue between the lobes of the parotid gland?
to allow the gland to be flexible to accommodate the motion of the mandible
what type of salvia does the parotid gland produce?
serous
what are the boundaries of the parotid region?
> superiorly — zygomatic arch
inferiorly — inferior border of mandible
anteriorly — masseter muscle
posteriorly — external ear and sternocleidomastoid
the secretions of the parotid gland are transported to the oral cavity by what?
the Stensen duct
describe the course of the stensen duct
- arises from the anterior surface of the gland
- transverse the masseter muscle
- it then pierces the buccinator, moving medially
- opens into the oral cavity near the 2nd upper molar
what happens to CN VII in the parotid gland?
it divides into 5 (or more) branches which leaver the gland on the anteromedial surface to innervate the muscles of facial expression — none of these nerves innervate the parotid gland itself
what types of innervation does the parotid gland receive?
sensory and autonomic
what supplies sensory innervation to the parotid gland?
auriculotemporal and greater auricular nerves
what supplies paraysympathetic innervation to the parotid gland?
auriculotemporal nerve
(glossopharyngeal nerve IX synapses with the otic ganglion, the auriculotemporal nerve then carries PS fibres from the otic ganglion to the parotid gland)
effects of parasympathetic vs sympathetic stimulation of parotid gland
PS - increase in saliva production, thin watery saliva
S - reduce in secretion of saliva, thicken saliva
what happens to the external carotid artery in the parotid gland?
it splits into its 2 terminal branches
what are the 2 terminal branches of the ECA?
the maxillary artery, superficial temporal artery
what unites in the parotid gland?
superficial temporal and maxillary veins to form the retromandibular vein
blood supply of the parotid gland
branches of the ECA
- superficial temporal
- maxillary
(indirectly - the transverse facial arteries)
where does the facial artery arise from?
ECA
where can the facial artery be palpated and where does it pass to?
- can be palpated as it wraps around the inferior border of the mandible just anterior to the masseter
- it passes superficially across the face to the medial canthus of the eye
what supplies the skin with blood over the frontal and parietal bones?
superficial temporal artery
what artery supplies the skin over the chin?
mental artery
where does the mental artery arise from?
maxillary artery = terminal branch of ECA
where do the supraorbital and supratrochlear arteries arise from?
ophthalmic artery = terminal branch of ICA
what gives rise to the transverse facial artery which supplies the parotid gland and duct, masseter and overlying skin?
superficial temporal
label the arteries
describe the veins forming from the superficial temporal and maxillary veins
label the veins
what does lymph from the scalp, face and neck drain into?
superficial ring of lymph nodes = submental, submandibular, parotid, mastoid and occipital — located at the junction of the head and neck
all lymphatic vessels from the head and neck drain directly or indirectly into what?
the deep cervical lymph nodes (a chain of nodes mainly located along the IJV in the neck)
where does lymph from the deep cervical nodes pass?
to the jugular lymphatic trunk which joins the thoracic duct on the LHS and the IJV or brachiocephalic vein on the RHS
what are the main functions of the tongue?
articulation, squeezing food into the oropharynx as part of deglutition (swallowing) and also involved in mastication, taste, and oral cleansing
what is the dorsal surface of the tongue covered in?
specialised mucosa for tase, keratinised stratified squamous epithelium
what demarcates the anterior and posterior parts (signifies junction between anterior 2/3 and posterior 1/3) on the dorsal tongue?
terminal sulcus
what is the foramen cecum?
frequently absent, but when present is the non-functional remnant of the proximal part of the embryonic thyroglossal duct from which the thyroid gland developed
what are the 4 types of papillae?
- vallate
- foliate
- fungiform
- filiform
which papillae contain taste receptors?
vallate, folate and fungiform
what papillae are for general sensation only?
filiform
which papillae are arranged in a v-shaped row and lie directly anterior to the terminal sulcus?
vallate
what is visible on either side of the lingual frenulum?
deep lingual vein
what is present on each side of the base of the frenulum that includes the opening of the submandibular duct from the submandibular salivary gland?
sublingual caruncle (papilla)
what is the epithelium of the ventral surface of the tongue?
lining mucosa, containing lamina propria and submucosa
the muscles from each side of the tongue meet where?
at a middle fibrous septum
describe the intrinsic muscles of the tongue
- there are 4 paired intrinsic muscles and they are named in the direction by which they travel:
- superior longitudinal, inferior longitudinal, transverse
and vertical - they affect the size and shape of the tongue (eg. tongue rolling) and have a role in a illustrating speech, eating and swallowing
the superior and inferior intrinsic tongue muscles act together to do what?
make the tongue short and thick and to retract the protruded tongue
the transverse and vertical intrinsic tongue muscles act together to do what?
make the tongue long and narrow
what supplies the motor innervation for the intrinsic tongue muscles?
hypoglossal nerve (CNXII)
what are the 4 extrinsic tongue muscles?
- geniohyoidus
- genioglossus
- hyoglossus
- styloglossus
label the extrinsic tongue muscles
origin, insertion and action of genioglossus
> O = superior mental spine of mandible
I = body of hyoid bone and intrinsic muscles of tongue
A = inferior fibres protrude the tongue, middle fibres depress the tongue, and superior fibres draw the tip back and down
origin, insertion and action of hyoglossus
> O = greater horn of hyoid bone
I = inferior aspects of lateral part of tongue
A = depresses and retracts tongue
origin, insertion and action of styloglossus
> O = styloid process of hyoid bone
I = sides of tongue
A = retracts and elevates tongue
origin, insertion and action of palatoglossus
> O = palatine aponeurosis
I = lateral aspect of tongue
A = elevates tongue, brings palatoglossal arches together
what provides general sensation to the anterior 2/3 of the tongue?
lingual nerve (posterior branch of V3)
what provides taste sensation to the anterior 2/3 of the tongue?
chorda tympani (branch of facial nerve)
what provides general sensation to posterior 1/3 of the tongue?
CN IX
what provides taste sensation to posterior 1/3 of tongue?
CN IX
what provides motor to muscles of the tongue? exception?
hypoglossal except palatoglossus = vagus
why would an UMN lesion not affect the platysma? LMN lesion?
- because the upper part of the facial motor nucleus is bilaterally innervated therefore the facial motor nucleus will still receive innervation from one side of the motor cortex
- however a LMN lesion would causes weakness/paralysis of the platysma
what crosses the infratemporal fossa on route to the pterygopalatine fossa?
maxillary artery
where does the maxillary artery arise?
in the parotid gland
what is the auriculotemporal nerve a branch of?
V3
what foramina transmits the inferior alveolar nerve?
mandibular foramen = T
what does U transmit?
mental foramen — mental nerve
what inserts at V, X and Z?
V = temporalis
X = medial pterygoid
Z = masseter
the submandibular gland receives PS innervation from what?
chorda tympani
what is the mneumonic for the branches of the ECA?
some anatomists like freaking out poor medial students
what are the 3 anterior branches of the ECA?
- superior thyroid
- lingual
- facial
what is the medial branch of the ECA?
ascending pharyngeal
what are the 2 posterior branches of the ECA?
occipital and posterior auricular
what are the 2 terminal branches of the ECA?
maxillary and superficial temporal
say all of the branches of the ECA and where they arise
what is the anastomoses between the ECA and ICA?
ophthalmic artery from ICA
What type of tissue underlies the mucosa of the posterior third of the tongue and is responsible for its nodular appearance?
lymphoid
