BIO 201 Muscles & Actions Unit 4 (Ch. 9)

Orbicularis oculi

closes eye; blinking

Orbicularis oris

closes lips; kissing

Zygomaticus major/minor

elevates corners of mouth; smiling

Masseter

Raises jaw; mastication (chewing)

Sternocleidomastoid

laterally flexes neck; rotates head; forceful inhalation

Trapezius

raises scapula & shoulder; shrugging / pulls head backward

Levator scapulae

elevates scapula

Serratus anterior

Pulls scapula down & forward; pushing

Pectoralis major

Flexes shoulder; adducts; rotates arm medially

Teres major

Extends shoulder; adducts; rotates arm medially

Latissimus dorsi

Extends shoulder; adducts; medial rotation; depresses & retracts shoulder / swim, climb, row

Deltoid

Abducts arm; flexes & extends shoulder

Biceps brachii

Flexes elbow; supinates

Brachioradialis

flexes elbow

Triceps brachii

Extends elbow

Pronator teres

Rotates arm medially; pronates forearm

Flexor carpi radialis

Flexes wrist and abducts hand

Palmaris longus

Flexes wrist

Extensor carpi radialis longus

Extends wrist and abducts hand

Extensor digitorum

Extends joints of fingers

External oblique

Compresses abdomen; flexes & rotates vertebral column

Rectus abdominis

Compresses abdomen; flexes vertebral column

Levator ani

Supports pelvic viscera; compresses anal canal

Sphincter urethrae

Closes urethra

Gluteus maximus

extends hip

Tensor fasciae latae

Abducts thigh, flexes hip, rotates thigh medially

Adductor longus

Adducts thigh and flexes hip

Sartorius

Flexes knee, hip; abducts, rotates thigh laterally; rotates leg medially

Gracilis

Adducts thigh and flexes knee

Hamstring group

Flexes knee

Quadriceps group

Extends knee

Tibialis anterior

Dorsiflexion; inversion of foot

Extensor digitorum longus

Extends toes; dorsiflexion of foot

Gastrocnemius

Plantar flexion of foot; flexes knee

Fibularis longus

Plantar flexion; eversion of foot; supports arch