Muscles Of The Face Flashcards
What is unique about the muscles of facial expression?
No superficial layer - layers are skin, deep fascia, bones/organs
What innervates the muscles of facial expression?
CNVII - the motor division
2 classes of muscles of facial expression
Sphincter muscles - open and close orifices, forming sites of attachment for muscles of facial expression proper
Muscles of facial expression proper - alter facial expression
What would happen if sphincteric muscles of the face were paralysed?
Their function as well as the muscles that attach to them lose their function.
Potential incompetence of opening and closing the eyes and mouth (often unilateral), trickling down of tears constantly and drooping of eyelid.
Which side do nerves innervate the sphincteric muscles?
Muscles are innervated by a nerve of the same side.
In the eye, which nerve controls opening and closure of the eye?
CNIII opens the eye while CNVI closes the eye
What are the deep and superficial attachments of the muscles of fascial expression?
Deep: bone or the orbital muscles
Superficial: skin (reason for altering facial expression due to change in tension of skin when muscles are active)
What else (apart from paralysis of CNVII) can cause an expressionless face?
Neurological conditions that affect motor tone of muscles of facial expression, e.g., parkinsonian face - an UMN sign, usually causing asymmetry.
What are the 3 main branches of CNVII?
Somatic motor (efferent) = facial nerve
Somatic sensory (afferent) = nervus intermedius
Autonomic efferent = greater petrosal nerve
Describe the route of the facial branch of CNVII
Facial motor nucleus in pons
Axons run up and down to form the facial colliculus
Nerve to stapedius branches off
Exits through stylomastoid foramen
Posterior auricular nerve and then nerve to posterior belly of digastric and stylohyoid branch off
Terminates as TZBMC
Describe the route of the greater petrosal nerve
Collection of preganglionic parasympathetic fibres starting at the superior salivatory nucleus
Fibres pass through the geniculate ganglion but do not synapse here, exiting as the greater petrosal nerve
Some fibres terminate in the pterygopalatine ganglion to supply the lacrimal gland and some fibres terminate in the submandibular ganglion to supplie the SMG and SLG
Describe the route of the nervus intermedius
Originates in nucleus solitarius
Some fibres will reach the geniculate ganglion, some will join the chorda tympani to supply anterior 2/3 of tongue
Also carries preganglionic parasympathetic fibres with it
What is the geniculate ganglion and where is it found?
Ganglion in the PNS within the temporal bone, sitting between the cochlear and tympanic cavity.
