Muscle anatomy (Spring 2021)

orbicularis oris

closes and protrudes lips

Trapezius

rotates and retracts scapula; hyperextends head

pectoralis major

Adducts and rotates arm medially; flexes shoulder

latissimus dorsi

extends shoulder; adducts and medially rotates arm

Deltoid

abducts arm

biceps brachii

flexes forearm

triceps brachii

extends forearm at elbow

gluteus maximus

extends thigh, laterally rotates hip

gluteus medius

abducts and medially rotates thigh

rectus femoris

extends leg at knee, flexes thigh at hip

Gastrocnemius

plantar flexes foot and flexes knee

tibialis anterior

dorsiflexes and inverts foot

rectus abdominis

flexes vertebral column and compresses abdomen

Diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

external intercostals

elevates ribs during inspiration

Frontalis

raises eyebrows, wrinkles forehead

internal intercostals

depresses ribs; forced expiration

Occipitalis

pulls scalp posteriorly

biceps femoris

extends thigh and flexes leg

quadriceps femoris (group of 4 muscles)

extend knee

Sartorius

Flexes, abducts, and laterally rotates thigh at the hip; flexes knee