Fundamentals of Anatomy and Physiology

The Muscular System

saw on the lateral upper side of the trunk. These muscles all
move the scapula. Table 9-3 lists the muscles that move the
shoulder girdle and the functions they perform.

Muscles Moving the Humerus

Most of the muscles that move the humerus originate on the
bones of the shoulder girdle (Figure 9-9). Table 9-4 lists the
muscles that move the humerus and the func-tions they
perform. The pectoralis major flexes and ad-ducts the
arm. The latissimus dorsi (lah-TISS-ih-mus DOR-sigh)
muscle extends, adducts, and rotates the arm medially.
Because these movements are used in swim-ming, this
muscle is often called the swimmer’s muscle.

Trapezius

Clavicle

215

The following muscles are often referred to as the ro-

tator cuff muscles. The teres minor adducts and rotates

the arm. The deltoid (DELL-toyd) abducts the arm and is

also the muscle that receives injections. The supraspina-

tus (sue-prah-spye-NAH-tus) also abducts the arm. The

infraspinatus- (in-frah-spye-NAH-tus) rotates the arm.

Muscles Moving the Elbow

Three muscles flex the forearm at the elbow: the bra-chialis

( bray-kee-AL-us), the biceps brachii (BYE-seps

BRAY-kee-eye), and the brachioradialis (bray-kee-oh-

ray-dee-AH-lus). Table 9-5 lists the muscles that move the

elbow and the functions they perform. Two muscles

Trapezius

Deltoid^
Deltoid^ Pectoralis major^

Triceps brachii (^)
(^) Biceps brachii—short head Triceps brachii
(^) Biceps brachii—long head (^)
Pronator teres (^) Brachioradialis (^)
(^) Brachialis (^) Extensor carpi
Anconeus
(^)
radialis longus (^)
(^) Brachioradialis (^) Extensor carpi
Flexor carpi
(^) Flexor carpi radialis radialis brevis^
ulnaris Extensor digitorum
Palmaris longus
Extensor
communis^
(^) Flexor carpi ulnaris
carpi ulnaris^ Extensor digiti quinti^
Flexor digitorum
proprius (^)
(^)
sublimis (^)
(^) ®
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Figure 9- 9 Muscles that move the arm and fingers: (A) anterior view, (B) posterior view.