Question

Muscle Actions Study Guide

Answer 1

just for memorization purposes honestly, will probably delete once thursday's exam is over

Answer 2

- buccinator: compresses cheeks (bucc = cheeks)
- risorius: draws corner of the mouth laterally
- platysma: lowers mandible, tenses neck skin
- depressor labii inferioris: depresses the lower lips (depressor = lowers, inferioris = lower, labii = lips)
- inferior rectus: makes eyes look down
- medial rectus: moves eye medially
- superior rectus: makes eyes look up
- lateral rectus: moves eye laterally
- superior oblique: moves eye up and laterally
- inferior oblique: moves eye down and laterally

Answer 3

- sternothyroid: depresses hyoid bone and larynx
- spinalis cervicis: extends neck (cervix = neck)
- spinalis thoracis: extends vertebral column
- longissimus capicitis + longissimus cervicis: extends the neck
- longissimus thoracis: extends vertebral column
- iliocostalis cervicis: extends + laterally flexes neck
- iliocostalis thoracis: stabilizes the thoracic vertebrae
- iliocostsalis lumborum: extends the vertebral column (notice: this is the same action as longissiumus thoracis)
- external intercostals: (e)levates rib (costals = ribs)
- internal intercostals: depresses the rib

Answer 4

- scalene anterior: elevates ribs + flexes neck
one side bends to the opposite side
- scalene middle/posterior: elevates ribs + flexes neck
one side bends to same side
- levator scapulae: raises scapula
- pectoralis minor: depresses + protracts shoulder so the glenoid cavity moves down
- brachioradialis: flexes elbow
- pronator teres: pronates arm (medial rotation)
- supinator: supinates arm (lateral rotation)
- flexor carpi radialis/flexor carpi ulnaris: flexion and adduction at wrist
- abductor pollicis longus: abducts joints at wrist
- extensor digitorum: extension at digits and wrist

Answer 5

- extensor indicis: extends index finger
- flexor digitorum superficialis: flexion at proximal interphalangeal, metacarpophalangeal, wrist joints
- opponens pollicis: opposition of thumb
- tensor fasciae latae: extension of knee and lateral rotation of leg, abduction and medial rotation of thigh
- piriformis: lateral rotation and abduction of hips
- adductor longus: adduction, flexion, medial rotation of hip
- gracilis: flexion and medial rotation at knee, adduction and medial rotation of hip
- iliacus: flexion at hip, flexion at intervertebral joint
- psoas major: flexion at hip, lumbar intervertebral joints
- semimembrinosus/semitendinosus: flexion at knee/extension and medial rotation of hip
- vastus laterialis: extends knee
- fibularis longus/brevis: eversion of foot, plantar flexion of ankle
- extensor digitorum longus: extension of toes