Head & Neck Muscles Flashcards
Sternocleidomastoid
Origin: manubrium of sternum, clavicle
Insertion: mastoid process
Action: rotates, flexes head
Sternohyoid
Origin: manubrium and clavicle
Insertion: hyoid bone
Action: depresses hyoid and larynx
Sternothyroid
Origin: manubrium
Insertion: thyroid cartilage
Action: depresses hyoid and larynx
Mylohyoid
Origin: mandible
Insertion: hyoid bone
Action: elevates hyoid
Thyrohyoid
Origin: thyroid cartilage
Insertion: hyoid bone
Action: depresses hyoid, elevates thyroid
Diagastric
Origin: mandible and mastoid process
Insertion: hyoid bone
Action: opens mouth, depresses mandible
Masseter
Origin: zygomatic arch
Insertion: angle and ramus of mandible
Action: elevates mandible (closes jaw)
Epicranius
Frontal belly action: raises eyebrows
Occipital belly action: pulls scalp posteriorly
Temporalis
Action: elevates and retracts mandible (closes jaw)
Orbicularis Oculi
Closes eyes (as in winking)
Orbicularis Oris
Puckers mouth (as in kissing)
Zygomaticus
Raises corners of mouth (as in smiling)
Risorius
Pulls corner of mouth back (as in smiling)
Buccinator
Compresses cheek (as in sucking)
Levator Lebii Superioris
Raises upper lip (as in snarling)
Superior Rectus
O: common ring tendon
I: anterior and superior surface
A: Elevates and adducts eyeball, intortion
Inferior Rectus
O: common ring tendon
I: anterior inferior surface
A: Depresses and adducts eyeball, extortion
Medial Rectus
O: common ring tendon
I: anterior medial surface
A: Abduction
Lateral Rectus
O: common ring tendon
I: anterior and superior surface
A: Elevation, intortion, abduction
Superior Oblique
O: sphenoid; orbit apex above common ring tendon
I: posterior temporosuperior quadrant
A: Depresses and abducts eyeball
Inferior Oblique
O: maxilla, behind lacrimal fossa
I: posterior temproinferior quadrant
A: Elevates and abducts eyeball, extortion
Levitator palpebrae superioris
O: Orbit apex above common ring
A: lid elevation
Medial and lateral pterygoid
O: sphenoid bone
I: mandible
A: medial - move mandible up and down (elevation)
Lateral - pull mandible forward (horizontal/transverse)
