Muscles of Facial Expression and sensory innervation to the face Flashcards
What are the different muscles of facial expression? (7)
- Frontalis
- Orbicularis oculi
- Quadratus superioris
- Depressors of the lip
- Buccinator
- Orbicularis oris
- Platysma
Describe the direction that ‘wrinkles’ follow.
They form at 90 degrees to muscle fibre detection (muscle fibre direction is up an downwards )
What can the quadratus (4) superioris be split up into? - from lateral to medial
4 PARTS:
- zygomaticus major
- zygomaticus minor
- levator (lift) labii (lip) superioris (towards top)
- levator (lift) labii (lip) superioris (towards top) alaequae (wing) nasi (nose)
what is the point of the buccal fat pat in the cheeks
it gives the cheeks volume to the face, without it, the cheeks would have a very sunken appearance.
what is the levator anguli oris
Lifts the angle of the mouth upwards
what is the depressor labii inferioris
this is a muscle which lowers the lip downwards
what is the depressor anguli oris
this is a muscle that brings the angle (corner) of the mouth downwards
what is the mentalis
This is a muscle sitting on the chin
what is the orbicularis oris
this is a muscle that circles the mouth
what is the connective tissue structure that we can refer to within the face?
the MODIOLOUS
what is the modiolous
located at the corner of the mouth on rhs and lhs and is a common site for multiple attachments of muscles used in facial expression.
What is the buccinator?
this is the muscle of the cheek - it attaches anteriorly to the orbicularis oris. posteriorly it attaches to the pterygomandibular raphe.
what is the frontalis muscle?
frontalis muscle sits at the front of the head and is connected via a tendon called the epicranial aponeurosis to a muscle called the occippitalis - forms a fronto-occipital complex (forms scalp)
what 2 parts is the orbicularis oculi composed of?
- orbital (external) - allows us to scrunch our eyes tightly.
- palpebral (internal/eyelid)- allows us to close our eyes gently.
list the 5 layers of the scalp superficial to deep
Skin
Connective tissue (HIGHLY VASCULARISED eg splitting head open)
Aponeurosis (tensile tendon - keeping arteries open preventing from them heeling naturally)
Loose connective tissue (thinner version of connective layer but not vascularised)
Pericranium (layer in direct contact with bones of skull)
what is the motor nerve supply to all muscles of facial expression?
ALL INNERVATED BY THE FACIAL NERVE CNVII
How can we test motor function of the facial nerve (CNVII) - BILATERALLY
- ask patient to frown
- ask patient to close eyes tightly
- ask pt to smile
- ask pt to puff out cheeks
Where does the facial nerve arise from?
From the brain, more specifically from the PONS (right and left)
Where does the facial nerve pass through?
The facial nerve passes through 2 places through the brain from the pons:
1st = exit the cranial cavity via the internal acoustic meatus, they then pass through the petrous temporal bone before exiting the base of the skull via the stylomastoid foramen (2nd)
where does the facial nerve pass through once through the base of the skull?
through the parotid gland branching onto the face.
Name the 5 nerves innervating the anterior part of the face
- temporal
- zygomatic
- buccal
- mandibular
- cervical
What happens to the right common carotid artery within the face?
it bifurcates into the right external carotid artery and the right internal carotid artery
Where does the right internal carotid artery lead to
continues within the neck without giving off any branches, and continue into the cranial cavity to supply the brain
where does the right external carotid artery lead to
will give off multiple branches onto the neck and the face, one branch being the facial artery.
describe the course that the facial artery takes along the face
it arises deep to the mandible, but will then cross the inferior border of the mandible in order to move up onto the face. Once on the face, it will move onto the corner of the mouth, then to the corner of the nose, before then travelling to the medial corner of the eye
How can we differentiate the facial artery from the facial vein
facial artery has a more tortuous course. Facial vein is very straight in its course.
What does the facial vein do?
Drains blood from the face down towards the internal jugular vein, returning it back towards the heart.
What is a dermatone?
The area of skin supplied by the sensory fibres in a given somatic nerve.
What are the three parts of the trigeminal nerve
Pt 1 - opthalmic (sensory)
pt 2 - maxillary (sensory)
pt 3 - mandibular (motor and sensory!) - BOTH
where on the face does CN V1 innervate
most of forehead, upper eyelid, bridge/tip of nose NOT nostrils
Where does CNV2 innervate on the face
temple region, onto prominence of cheek, nostrils and top lip ONLY.
what does CNV3 innervate on the face
posterior region of temple, onto beard line, onto prominence on chin and LOWER LIP.
what nerve is the angle of the mandible supplied by
the great auricular nerve
Name the MAIN branch of the opthalmic division in terms of sensory nerve supply to the face
supra-orbital nerve supplying forehead
name the MAIN nerve branch of the maxillary division
infra-orbital nerve (supplying the majority of the mid-face and upper lip)
name the MAIN nerve branch of the mandibular division
Mental nerve supplying majority of lower face and lower lip
where do the supra-orbital nerves come through in the skull?
supra-orbital foraminae
where do the infra-orbital nerves pass through
infra-orbital foraminae
where do they mental nerves pass through
mental foraminae
How can we clinically test the sensory component of the trigeminal nerve?
- ask pt to close there eyes
- gently brush the skin in each dermatome with cotton wool
- ask pt to tell you when they feel there skin being touched
- compare the 2 sides
