Muscles of facial expression (A15) Flashcards
general structure of facial skin (layers from superficial to deep)
- epidermis
- dermis
- superficial fascia
- deep fascia
which layer of facial skin are the muscles of facial expression within
superficial fascia layer (most muscles of the body are deep to the deep fascia therefore the muscles of facial expression are very superficial and almost all attach directly to skin therefore you have to be careful when removing the skin during dissection)
what is special about the structure of facial skin
there is very little deep fascia on the face (there is only sufficient amounts around the masseter muscle and parotid gland at the back)
what is the origin of the muscles of facial expression
mainly have origin on bone or fascia or directly connect to facial bones and almost all attach directly to skin
importance of muscles of facial expression (and clinical importance)
communication without words (clinically important in conditions such as bells palsy as a viral infection of the facial nerve can cause lack of function of buccinator muscle etc and patient has difficulty moving food to back of mouth without aid of finger, or lack of facial expression muscle function can cause drooping of eye/drying of the eye/ulceration etc)
buccal (cheek) fat pad
dense fat pad deep inside cheeks, only not present when patient is malnourished and is more distinct/important in babies and children as it is thought to stop cheeks collapsing during suckling/ also thought to help masseter muscle move freely during facial expression movements
vermillion border
border that runs outside the lips/ transitional zone between the skin of face and the mucous membrane (lips themselves are a mucous membrane)
why are lips red
due to the very superficial blood supply
direction of facial wrinkles (formed during facial expression)
form at 90degree angles to the muscle fibre direction
muscles of facial expression
2 of each (1 on left and right side of face)
- frontalis
- orbicularis oculi
- quadratus superiorus (made up of 4 individual muscles)
- levator anguli oris
- depressors of the lip (depressor anguli oris, depressor labii inferioris)
- mentalis
- orbicularis oris
- buccinator
- platysma
frontalis muscle
big muscle of forehead, involved in wrinkling of forehead/raising eyebrows
orbicularis definition
orbit/ goes around
sphincter of the mouth
orbicularis oris
sphincter of the eye
orbicularis oculi
function of quadratus superioris
is attached to/helps move superior lip
4 muscles that make up quadratus superioris
- zygomaticus major
- zygomaticus minor
- levator labii superioris
- levator labii superioris alequae nasi
depressors of the lip
attach to either lower lip or angle of the lip and depress the lip
buccinator
muscle of cheek
zygomaticus major
(one of 4 muscles that make up quadratus superioris), attaches onto zygomatic bone and extends to the corner of the mouth, draws the mouth’s angle upward and outward)
zygomaticus minor
connects to the orbicularis oculi, arising at zygomatic bone, attaches at the top of the check below each eye and extends diagonally down and to the outside of each end of the upper lip
levator labii superioris
elevates superior/upper lip, shaped like a broad, flat sheet that starts next to the nose and extends to the zygomatic bone
levator labii superioris alaeque nasi
(alaeque nasi= wings of nose), attaches to wings of nose helping to flare nostrils/ dilate nostrils and elevates upper lip