Muscles Which Move The Humerus

Front 1

Pectoralis Major

Back 1

Origin: Clavicle: (clavicular head), sternum, and costal cartilages of ribs 2-6 and sometimes ribs 1-7 (sternocostal head)

Insertion: Greater tubercle and lateral tip of the intertubicular sulcus of humerus

Action: As a whole, adducts and medially rotates arm at shoulder joint; clavicular head flexes arm, and sternocostal head extends the flexed arm to side of trunk

Front 2

Latissimus Dorsi

Back 2

Origin: Spines of T7-T12, lumbar vertebrae crests of sacrum and illium, ribs 9-12

Insertion: Intertubercular sulcus of humerus

Action: Extends, adducts, and medially rotates arm at shoulder joint; draws arm inferiorly and posteriorly

Front 3

Pectoralis Major

Back 3

large, fan shaped muscle that covers the superior part of the thorax

Front 4

Latissimus dorsi

Back 4

a broad triangular muscle located on the inferior part of the back

known as "swimmer's muscle"

Front 5

Deltoids

Back 5

Origin: Acromial extremity of clavicle (anterior fibers), acromion of scapula (lateral fibers), and spine of scapula

Insertion: Deltoid tuberosity of humerus

Action: Lateral fibers abduct arm at shoulder joint; anterior fibers flex and medially rotate arm at shoulder joint; posterior fibers extend and laterally rotate arm at shoulder joint

Front 6

Deltoids

Back 6

thick powerful muscles that covers the shoulder joint and forms the rounded contour of the shoulder

Front 7

Teres major

Back 7

Origin: Inferior angle of scapula

Insertion: Medial tip of intertubercular sulcus of humerus

Action: Extends arm at shoulder joint and assists in adduction and medial rotation of arm at shoulder joint

Front 8

Teres minor

Back 8

Origin: Inferior lateral border of scapula

Insertion: Greater tubercle of humerus

Action: Laterally rotates, extends, and adducts arm at shoulder joint