Actions of Muscles Flashcards
Trapezius (A)
Rotate, elevate, retract, and depress scapula
Latissimus dorsi (A)
Agonist of arm extension; adducts and medially rotates arm
Deltoid (A)
AF: Flex & medially rotate arm
MF: Agonist of arm abduction
PF: Extend and laterally rotate arm
Pectoralis Major (A)
Agonist of arm flexion
Also, adducts (horizontally) and medially rotate arm
Biceps brachii (A)
Flexes forearm, powerful supinator of forearm
Long head flexes arm
Psoas Major (A)
Iliacus (A)
Flexes thigh
Gluteus Maximus (A)
Extends thigh; laterally rotates thigh
Rectus Femoris (A)
Flexes thigh, extends leg
Tibialis Anterior (A)
Dorsiflexes foot; inverts foot
Gastrocnemius (A)
Flexes leg; plantar flexes foot
Frontal Belly of Occipitofrontalis (A)
Moves scalp, eyebrows; wrinkles skin of forehead
Orbicularis Oculi (A)
Close eyes; produces winking, blinking, squinting
Depressor Anguli Oris (A)
Draws corners of mouth inferiorly and laterally (“frown” muscle)
Zygomaticus Major (A)
Elevates corner of the major
Masseter (A)
Elevates and protracts mandible; prime mover of jaw closure
Sternocleidomastoid (A)
Unilateral action: lateral flexion, rotation of the head to the opposite side
Bilateral action: flexes neck
Splenius Capitis (A)
Unilateral action: turns head to same side
Bilateral action: Extends head/neck
Diaphragm
The contraction causes flattening of the diaphragm (moves inferiorly), thus expanding of thoracic cavity; increases pressure in the abdominopelvic cavity
External Oblique
Unilateral action: Lateral flexion of the vertebral column; rotation of vertebral column to the opposite side
Bilateral Action: Flexes vertebral column and compresses abdominal wall; used in forced exhalation
Rectus Abdominis
Flexes vertebral column; compresses abdominal wall; used in forced exhalation
