Facial muscles

Question 1

What are the 5 muscles of facial expression?

Answer 1

Occipitofrontalis
Orbicularis Oculi
Orbicularis Oris
Buccinator
Platysma

Question 2

Describe the occipitofrontalis muscle

Answer 2

There are two bellies - occipital and frontal
Bellies are joined via the epicranial aponeurosis

Occipital belly:
PA: superior nuchal line (lateral 2/3)
DA: epicranial aponeurosis

Frontal:
PA: epicranial aponeurosis
DA: skin and subcutaneous tissue of eyebrows and forehead

NS:
CNVII Facial
via Facial Motor Nucleus in caudal pons
(brachial motor)

A: elevates eyebrows, winkles skin on forehead, retracts scalp

Question 3

Describe the orbicularis oculi

Answer 3

A sphincter shaped muscle encircling the eye
Two parts - palpebral (inner) orbital (outer)

PA: medial orbital margin, medial palpebral ligament and lacrimal bone

DA: skin around margin of orbit; superior and inferior tarsal plates

NS:
CNVII Facial
via Facial Motor Nucleus in caudal pons
(brachial motor)

A: closes eyelids (both).
Palpebral (gently)
Orbital (tightly)

Question 4

Describe the orbicularis oris

Answer 4

Sphincter of mouth

PA: maxilla and mandible, angles of mouth
DA: mucous membranes of lips
NS: CN VII Facial (via Facial Motor Nucleus in caudal pons, brachial motor fibres)
A: holds lips closed, compresses and protrudes lips

Question 5

Describe the buccinator

Answer 5

PA: alveolar processes of maxilla and mandible

DA: angle of mouth and orbicularis oris

NS: CN VII Facial (via Facial Motor Nucleus in caudal pons, brachial motor fibres)

A: presses cheek against molar teeth, resists distention of cheeks when blowing

Question 6

Describe the platysma

Answer 6

(contained within subcutaneous fascia of the neck)

PA: subcutaneous fascia of the supraclavicular and infraclavicular regions

DA: mandible, skin of cheek and lower lip

NS: CN VII Facial (via Facial Motor Nucleus in caudal pons, brachial motor fibres)

A: depresses mandible, tenses skin of inferior face and neck

Question 7

What is the nerve supply for the muscles of facial expression?

Answer 7

CN VII facial nerve

via brachial motor nerve fibres and facial motor nucleus in caudal pons