Info

Muscle

Origin

Insertion

Action

Nerve Supply

Coracobrachialis

Coracoid process of scapula

Shaft of humerus

Flexes and adducts the arm

Musculocutaneus n.

Pectoralis major

Clavicle, sternum, and costal cartilages of upper ribs

Intertubercular groove of humerus

Flexes, adducts, and rotates arm medially

Pectoral n.

Teres major

Lateral border of scapula

Intertubercular groove of humerus

Extends, adducts, and rotates arm medially

Lower subscapular n.

Latissimus dorsi

Spines of sacral, lumbar, and lower thoracic vertebrae, iliac crest, and lower ribs

Intertubercular groove of humerus

Extends, adducts, and rotates the arm medially, or pulls the shoulder downward and back

Thoracodorsal n.

Supraspinatus

Posterior surface of scapula above spine

Greater tubercle of humerus

Abducts the arm

Suprascapular n.

Deltoid

Acromion process, spine of the scapula, and the clavicle

Deltoid tuberosity of humerus

Abducts, extends, and flexes arm

Axillary n.

Subscapularis

Anterior surface of scapula

Lesser tubercle of humerus

Rotates arm medially

Subscapular n.

Infraspinatus

Posterior surface of scapula below spine

Greater tubercle of humerus

Rotates arm laterally

Suprascapular n.

Teres minor

Lateral border of scapula

Greater tubercle of humerus

Rotates arm laterally

Deltoid

Short head of. biceps brachii

Long head of. biceps brachii

Trapezius.

Deltoid

Short head of. biceps brachii

Long head of. biceps brachii

Subscapularis

Clavicle Subscapularis

Coracobrachialis

Medial border of scapula

Brachialis

Coracobrachialis.

Clavicle Subscapularis

Coracobrachialis

Medial border of scapula

Brachialis

Coracobrachialis.

Biceps brachii (short and long heads)

Biceps brachii (short and long heads)

Subscapularis
Brachialis

Figure 9.29

(a) Muscles of the anterior shoulder and the arm, with the rib cage removed. (b, c, and d) Isolated views of muscles associated with the arm.

Muscles that move the arm include the following:

Abductors

Flexors

Coracobrachialis Pectoralis major

Extensors

Teres major Latissimus dorsi

Supraspinatus Deltoid

Rotators

Subscapularis Infraspinatus Teres minor

Flexors

The coracobrachialis (kor"ah-ko-bra'ke-al-is) extends from the scapula to the middle of the humerus along its medial surface. It flexes and adducts the arm (figs. 9.28 and 9.29).

The pectoralis major is a thick, fan-shaped muscle located in the upper chest. Its fibers extend from the center of the thorax through the armpit to the humerus. This muscle primarily pulls the arm forward and across the chest. It can also rotate the humerus medially and adduct the arm from a raised position (fig. 9.26).

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