Facial muscles Flashcards
What are all the muscles of facial expression innervated by?
Facial nerve (CN VII)
Which two facial muscles are associated with the orbital group?
Orbicularis oculi
Corrugator supercilii
What is the function of the orbicularis oculi?
Closes the eyelids
Name and describe the two major parts of the orbiculris oculi?
Outer orbital part - broad ring encircling the orbital orifice and extends beyond orbital ring
Inner palpebral part - in the eye lids, consisting of muscle fibres arching from medial to lateral corners of the eye
What is the difference between the palpebral and orbital parts of the orbicularis oris?
Both close the eyes
- palpebral gently
- orbital - forcefully
Describe the corrugator supercilii.
Deep to eyebrowns and orbicularis oris.
Active during frowning
Arises from superciliary arch, passing up+laterally to insert into the skin of the medial half of the eyebrow
What is the function of corrugator supercilii?
Draws eyebrows towards midline, causing vertical wrinkles above nose
Which three muscles are in the nasal group?
Nasalis
Procerus
Depressor septi nasi
What are the two parts of the nasalis?
Transverse part
Alar part
What is the function of the transverse part of the nasalis?
Compresses the nares and forms an apopneurosis with its partner across the dorsum of the nose
What is the function of the alar part of the nasalis?
Opens the nares
Describe the action of the procerus muscule.
Draws the medial border of the eyebrows downward to produce wrinkles over the bridge of the nose
Describe the action of the depressory septi nasi.
Pulls the nose inferiorly, assisting the alar part of the nasalis to open the nares
What is the function of the oral group, and what do they include?
They move the lips and cheek
- orbicularis oris
- buccinator
- upper and lower group of muscles
What is the function of orbicularis oris?
Narrows mouth, closes and purses lips
Which is the deepest muscle of the cheek?
Buccinator
What is the function of the buccinator muscle?
Forces air of out cheeks
Keeps cheecks taut and aids mastication by preventing food accumulation between teeth and cheeks
Name the lower group of muscles (part of the oral group)
Depressor anguli oris
Depressor labii inferioris
Mentalis
Describe the action of depressor anglui oris
Active during frowning
Depresses the corner of the mouth
Describe the action of depressor labii inferioris.
Depresses the lower lip and moves it laterally
Describe the action of the mentalis muscle.
Raises and protrudes the lower lip as it wrinkles the skin
Name the muscles within the upper group of muscles (part of the oral group).
Risorius Zygomaticus major + minor Levator labii superioris Levator labii superioris alaeque nasi Levator anguli oris
Describe the action of the risorius muscle.
Helps produce a grin.
Extends laterally from corner of mouth in an upwards direction - so contraction pulls corner of mouth laterally and upwards
Describe the action of zygomaticus major and minor muscle.
Helps produce a smile, raiseing corner of the mouth and moving laterally.
Describe the action of levator labii superioris.
This deepens the furrow between the nose and the corner of the mouth during sadness
Describe the action of levator labii superioris alaeque nasi.
This is medial to the levator labii superioris and assits in flaring the nares
Describe the action of levator anglui oris.
Deep to other levators and zygomaticus muscles.
Elevates corner of mouth and helps deepen nose-mouth furrow when sad.
Describe the platysma muscle
Large, thin sheet of muscle in superficial fascia of neck
What is the function of the platysma muscle?
Tenses the skin of the neck and can move lower lip and corners of the mouth down
Describe the articular muscles
Anterior, superior and posterior auricular muscles
What is the function of the articular muscles?
Anterior - pulls the ear upwards and forwards
Superior - elevates the ear
Posterior - retracts and elevates the ear
Describe the occipitofrontalis muscle
Associated with the scalp
Consists of a frontal belly and occipital belly with a connecting aponeurotic tendon
What is the function of the occipitofrontalis muscle?
Moves the scalp and wrinkles the forehead
What are the muscles of mastication?
Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
What is the main difference between the muscles of facial expression and the muscles of mastication?
Muscles of mastication are supplied by the Trigeminal nerve, while the muscles of facial expression are supplied by the Facial nerve.
Describe the masseter and its location.
The most powerful muscle of mastication
Quadrangular in shape
Superficial to pterygoids and temporalis
What is the function of the masseter muscle?
Elevates the mandible - closing the mouth
Describe the temporalis.
Originates from temporal fossa and inserts on the coronoid process of the mandible
What is the function of the temporalis muscle?
Elevates the mandible - closing the mouth
Retracts the mandible, pulling the jaw posteriorly
What is the function of the medial pterygoid muscle?
Elevates the mandible, closing the mouth
Describe the medial pterygoid muscle.
Quadrangular in shape, with two heads
Located inferiorly to the lateral lterygoid
Describe the lateral pterygoid muscle
Triangular in shape with two heads
Horizontally orientates muscle fibre
What is the function of the lateral pterygoid muscle muscle?
It’s a major protracter of the mandible
Produces side to side movement of the jaw
