Details the muscles of facial expression, muscles of mastication, muscles of the hyoid bone, muscles of auditory ossicles, muscles of the vertebral column (cervical region/posterior side/lumbar region/anterior abdominal wall muscles) and their features and movements
Axial Musculature
Monday, 20 September 2021 4:57 PM
Muscles of facial expression
- Subcutaneous layer beneath the skin
- Usually thin and flat
o When contract – they pull the skin
- Innervated by facial nerve – CN VII
- Occipitofrontalis – OF
o Only muscle that covers around neurocranium
o Rest located superficial to facial skeleton
o Frontal and occipital bellies
§ One part at forehead other behind head
o In between the two there’s a large sheet of aponeurosis
§ Flat tendon
• Not seen in appendicular musculation
§ Contraction elevates the eyeball
• Make wrinkles on forehead
o Origin at epicranial aponeurosis
o Insertion at skin of eyebrows and root of nose
- Orbicularis oculi – OC
o Surrounds the eye socket and extends to the eyelid
o Contraction causes closure of eyes
§ Damage – can’t close eyes
o Origin at Nasal part of frontal bone
o Insertion at adjacent muscles
- Zygomaticus major / minor – ZMa/ZMi
o Origin at zygomatic arch
o Inserts into angle of mouth
o Draws corner of mouth upwards and laterally
o Major
§ Elevates angle of the mouth
o Minor
§ Elevates the upper lip
§ Runs parallel with
§ Origins from anterior part of arch
§ Inserts to a slightly medial to corner of mouth
§ Draws corner of mouth upwards and laterally
• Can pull upper lip upwards slightly
o Exposes teeth
- Orbicularis oris – OR
o It encircles the mouth
o controls opening / closing of mouth in speech and chewing
o Contraction shuts the mouth
, • Can pull upper lip upwards slightly
o Exposes teeth
- Orbicularis oris – OR
o It encircles the mouth
o controls opening / closing of mouth in speech and chewing
o Contraction shuts the mouth
§ Compression and protrusion of lips
o Inserts into mandible / maxillae
- Buccinator – B
o Deep layer of muscle
o Forms elements of the cheek
o Origin at mandible / maxillae
o Inserts into corner of the mouth
o Contraction presses cheeks towards the teeth
o Use during eating to remove food stuck
o Contract together during whistling with orbicularis oris
- Risorius – R
o Runs laterally
o Origin at mandible
o Inserts to corner of mouth
o Contraction draws corner of mouth laterally
§ Weird smile
- Levator anguli oris – LAO
o Runs more vertically
o Originates at maxillae
o Inserts into corner of mouth
o Pulls upwards and medially instead of laterally
§ Exposes canine teeth
- Depressor anguli oris – DAO
o Depresses corner of mouth
o Origins from interior of mandible
§ Inferior to molar and canine tooth
o Inserts into corner of mouth
- Mentalis – M
o Deep layer muscle
o Runs from inferior edge of mandible superiorly
o Originates from mandible
o Inserts to skin of chin
o Contraction elevates skin of chin
§ Elevates and protrudes lower lip
- Platysma – P
o Thin and dark piece of muscle
o Runs from inferior edge of mandible to the clavicle
o Origin at clavicle
o Inserts to mandible
o Runs superiorly
o Slightly blends with muscles around the mouth near mandible
o Contraction depresses the mandible
o Very superficial
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