Posterior Back Muscles

levator scapulae

elevates and adducts scapula

Coracobrachialis

flexes and adducts arm

deltoid

abducts arm

Supraspinatus

abducts arm

Subscapularis

medially rotates arm

latissimus dorsi

Extends, adducts, and medially rotates the arm; draws the shoulder downward and backward

Infraspinatus

rotates arm laterally

teres minor

rotates arm laterally

rhomboid major

adducts scapula

teres major

extends, adducts, and medially rotates arm

Trapezius

Elevates, depresses, retracts, and rotates the scapula; rotates the arm

Trapezius

O=occipital bone, C1-7, T1-12 spinous process; I= acromion process of scapula; Raise arm, raise & rotate scapula, extend head

levator scapulae

O = transverse processes of C1-C4; I = medial margin of scapula; to raise scapula

Deltoid

O=acromion process and spine of scapula & clavicle; I=lateral edge of humerus; Abducts arm

Rhomboideus major

O= spinous process of thoracic vertebrae; I= medial border of scapula; raise, adduct & retract scapula

Teres major

O=lateral border of scapula; I=intertubercular groove of humerus; extends, adducts & medially rotates arm

Teres minor

O: lateral border of scapula;
I: greater tubercle of humerus; laterally rotates arm

Infraspinatus

O= posterior surface of scapula below spine; I=greater tubercle; rotates arm laterally

Supraspinatus

O= posterior scapula above spine; I=greater tubercle; abducts arm

Subscapularis

O=anterior side of scapula; I=lesser tubercle; rotates arm medially

Lattisimus dorsi

O=vertebral column; I=intertubercular groove of humerus; extends, adducts, and medially rotates arm

Coracobrachialis

O=coracoid process of scapula; I=shaft of humerus; flexes and adducts arm