AP1U4 Lab: Muscles of the arm, wrist and hand

rotator cuff muscles

1. supraspinatus 2. infraspinatus 3. teres minor 4. subscapularis

extensor digitorum

Extends fingers and the wrist, flare (abduct) fingers

extensor carpi radialis brevis

Extends wrist and abducts hand

extensor carpi radialis longus

Extends wrist and abducts hand

latissimus dorsi

Extends, adducts, and medially rotates the arm; draws the shoulder downward and backward - prime mover of arm extension - bringing arm down in a power stroke such as with a hammer

Infraspinatus

Laterally rotates shoulder; stabilizes the head of the humerus in glenoid cavity; one of the "rotator cuff" muscles

Supraspinatus

abduction of arm stabilizes the shoulder joint

pronator teres

acts synergistically with pronator quadrates to pronate forearm -weak elbow flexor

supinator

acts with biceps brachia to supinate the forearm antagonist of pronator muscles

teres major

extends, adducts, and medially rotates arm synergist of latissimus dorsi

Coracobrachialis

flexes and adducts arm

palmaris longus

flexes wrist (weak) tenses skin and fascia of the palm

flexor carpi radialis

flexes wrist and abducts hand

brachialis

major forearm flexor

Subscapularis

medially rotates arm, stabilizes the shoulder joint

biceps brachii

powerful flexion at elbow, supination of forearm -turns the corkscrew and pulls the cork. -weak arm flexor

flexor carpi ulnaris

powerful flexor of wrist; adducts hand

triceps brachii

powerful forearm extensor; antagonist of biceps brachii and brachialis

Deltoid

prime mover of arm abduction can aid in flexion, extension and rotation of the humerus

pectoralis major

prime mover of arm flexion; adducts, medially rotates arm pulls chest up in forced respiration

teres minor

rotates arm laterally, similar to infraspinatus

bracioradialis

synergist in forearm flexion