Practical 2- muscle list (exercise 13)
What is the action of lateral rectus muscles?
abducts the eyeball- innervated by CN VI
What is the action of superior oblique muscles?
abducts, depresses and medially rotates (intorsion) the eyeball - innervated by CN IV
What is the action of inferior oblique muscles?
abducts, elevates and laterally rotates (extorsion) the eyeball - innervated by CN III
What is the action of medial rectus muscles?
adducts the eyeball- innervated by CN III
What is the origin of palatoglossus?
anterior surface of soft palate
What is the origin of hyoglossus?
body and greater horn of hyoid
What is the action of orbicularis oculi?
closes eyes, blinking, squinting & draws eyebrows inferiorly
What is the action of orbicularis oris?
closes lips; purses and protrudes lips (kissing and whistling muscle)
What is the action of temporalis muscles?
closes mandible; elevates & retracts jaw
What is the action of genioglossus?
depresses & protracts tongue, in concert with other muscles can retract tongue too
What is the action of hyoglossus?
depresses and retracts tongue
What is the action of depressor anguli oris?
depresses corner of mouth
What is the action of the thyrohyoid muscle?
depresses hyoid bone; elevates larynx (from thyroid cartilage) if hyoid is fixed
What is the action of sternothyroid?
depresses larynx and hyoid bone
What is the action of the sternohyoid muscle?
depresses larynx and hyoid bone if mandible is fixed, it can also flex skull
What is the action of the omohyoid muscle?
depresses larynx, depresses and retracts hyoid bone
What is the action of depressor labii inferioris?
depresses lower lip
What is the action of inferior rectus muscles?
depresses, adducts and laterally rotates (extorsion) the eyeball - innervated by CN III
What is the origin of sternothyroid?
dorsal surface of manubrium of sternum and 1st costal cartilage
What is the action of the buccinator?
draw corner of mouth laterally; compresses cheek (as in whistling); holds food between teeth during chewing
What is the action of stylohyoid?
elevates and retracts hyoid bone, elongating floor of mouth during swallowing, elevates larynx
What is the action of levator anguli oris?
elevates corner of mouth
What is the action of the mylohyoid muscle?
elevates hyoid bone and base of tongue enabling tongue to exert backwards and upward pressure that forces food bolus into pharynx; depresses mandible
What is action of digastric muscle?
elevates hyoid bone; elevates larynx; open mouth and depresses mandible and steady it during swallowing and speech
What is the action of the masseter muscles?
elevates mandible & closes jaw
What is the action of the medial pterygoid?
elevates mandible; in conjunction with lateral pterygoid aids in grinding movements of teeth (lateral excursion)
What is the action of palatoglossus?
elevates tongue, depresses soft palate
What is the action of superior rectus muscles?
elevates, adducts and medially rotates (intorsion) the eyeball - innervated by CN III
What is the insertion of digastric muscle?
hyoid bone
What is the insertion of mylohyoid?
hyoid bone
What is the insertion of stylohyoid?
hyoid bone
What is the insertion of the geniohyoid muscle?
hyoid bone
What is the insertion of the omohyoid muscle?
hyoid bone
What is the insertion of the sternohyoid muscle?
hyoid bone
What is the insertion of the thyrohyoid muscle?
hyoid bone
What is the insertion of genioglossus?
inferior aspect of the tongue; body of hyoid bone
What is the insertion of hyoglossus?
inferolateral tongue
What is the insertion of palatoglossus?
inferolateral tongue
What is the insertion of styloglossus?
inferolateral tongue
What is the origin of the geniohyoid muscle?
inner surface of mandible
What is the origin of genioglossus?
internal surface of mandible near symphysis
What is the origin of digastric muscle?
lower margin of mandible (anterior belly) and mastoid process (posterior belly)
What is the origin of the sternohyoid muscle?
manubrium and medial end of clavicle
What is the origin of the sternocleidomastoid muscle?
manubrium of sternum and medial aspect of clavicle
What is the insertion of the sternocleidomastoid muscle?
mastoid process of temporal bone and superior nuchal line of occipital bone
What is the origin of mylohyoid?
medial surface of mandible
What is the action of lateral pterygoid?
protracts jaw; in conjunction with medial pterygoid aids in grinding movements of teeth
What is the action of risorius?
pulls corner of lips laterally; tenses lip
What is the action of the geniohyoid muscle?
pulls hyoid bone superiorly and anteriorly, shortening floor of mouth and widening pharynx for receiving food
What is the action of levator labii superioris?
raises and furrows upper lips, opens lips
What is the action of epicranium- frontal belly?
raises eyebrows, wrinkles forehead
What is the action of zygomatic minor?
retracts & elevates upper lip
What is the action of zygomatic major?
retracts & raises lateral corners of mouth upward (smiling muscle)
What is the action of styloglossus?
retracts and elevates tongue
What is the action of the sternocleidomastoid muscle?
simultaneous contraction: flexion forward of the neck independent contraction: rotates head toward shoulder on opposite side, and laterally flexes head to its own side
What is the origin of styloglossus?
styloid process of temporal bone
What is the origin of stylohyoid?
styloid process of temporal bone
What is the origin of the omohyoid muscle?
superior border of scapula
What is the action of epicranium- occipital belly?
tenses and retracts scalp
What is the action of temporoparietalis?
tenses scalp, moves auricle of ear
What is the action of platisma?
tenses skin of neck and depresses mandible; pulls lower lip back and down (produces downward sack of mouth)
What is the insertion of sternothyroid?
thyroid cartilage of larynx
What is the origin of the thyrohyoid muscle?
thyroid cartilage of larynx
