face and scalp Flashcards
where does the thickened fascia of the parotid gland arise from?
it is an extension of the deep fascia
the layer of deep cervical fascia covers the masseter and inserts into the parotid gland
describe the composition of fronto-occipitalis
there are two bellys:
- frontalis
- occipitalis
what is the innervation common to all muscles of facial expression?
the facial nerve
what is the function of platysma?
tightens the skin on the neck and contributes to facial expression
what nerve innervates platysma?
the facial nerve
what is the function of buccinator?
prevent food from collecting between the teeth and the cheek
what is the function of obicularis oculi?
it forms a circle around the eye and acts to close the eye
what is the function of orbicularis oris?
it forms a circle around the mouth and acts to close the mouth
is a more complex sphincter than obicualris oculi
what is the function of zygomaticus?
acts to raise the corners of the mouth
what is the function of levator labii?
acts to elevate the lips
what is the function of levator angulii superioris?
acts to elevate the corners of the mouth
what is the function of depressor labii?
acts to pull down the lips
what is the function of depressor anguli oris?
acts to pull down the corners of the mouth
what is the function of mentalis?
it is a small muscle that helps pull down the lower lip
where does risorius arise from and what is its function?
arises from the fascia above the carotid and attaches to the corner of the mouth and is used to make a happy smiling impression
what is the function of levator labii superiors alaeque?
it is a small muscle that helps to move the skin of the nasal area
what is the function of the facial nerve?
innervates the muscles of facial expression and so is motor supply to the face
what is the function of the trigeminal nerve?
supplies sensory innervation to the face and motor innervation to temporalis and masseter
how does the facial nerve emerge onto the face?
passes through the parotid gland
where does the facial artery arise from?
the third anterior branch of the external carotid artery
explain the course of the facial artery
it crosses the anterior surface of the mandible and forms branches that supply the face
it is torturous in shape and forms many bends as it crosses the face
explain the arterial supply to the forehead
the supratrochlear and supraorbital branches derived from branches of the internal carotid artery supply the forehead
explain the venous drainage of the face
the face is drained by the facial vein which drains into the internal jugular vein
what plexus does the facial vein communicate w/?
the pterygoid venous plexus that lies inside the infratemoporal fossa
what are the layers of the scalp from external to internal?
external:
S - skin
C - connective tissue
A - aponeurosis (between frontalis and occipitais)
L - loose areolar connective tissue
P - periosteum (pericardium)
how can the facial vein be differentiated from the facial artery?
the facial vein is much less torturous
explain the arterial supply to the anterior part of the scalp
supratrochlear and supraorbital arteries are derived from branches of the internal carotid artery and supply the anterior part of the scalp
describe the arterial supply to the rest of the scalp (not the anterior part)
the rest of the scalp is supplied by posterior branches of the external carotid artery and the superficial temporal artery which is a terminal branch of the external carotid
how do the veins of the scalp communicate w/ the sagittal dural venous sinus inside the skull?
via emissary veins
describe the potential route for infection to spread from superficial structures to the meninges
the emissary veins pass through the skull to the sagittal dural venous sinus
which nerve innervates the superior, anterior and lateral surfaces of the scalp?
branches of the trigeminal nerve
describe the innervation of behind the auricle and posterior surface of the head
behind the auricle and the posterior surface of the head are innervated by local nerves derived from C2 an C3 nerve roots
what nerve supplies sensory innervation to the face?
the trigeminal nerve
how does the supraorbital nerve reach the forehead?
exits the skull at the supraorbital notch
how does the infraorbital nerve reach the lateral sides of the nose and lip?
it leaves the skull at the infraorbital foramen
how does the inferior alveolar nerve end?
ends as it passes through the mental foramen to form the mental nerve that passes onto the side of the mandible
why is there no C1 dermatome?
because it is replaced by the divisions of the trigeminal nerve
where do the C2 and C3 dermatomes cover?
C2 - posterior part of the head
C3 - much of the neck
ultimately where does lymph from the face and scalp drain into?
deep cervical nodes which lie close to the internal jugular vein
