Muscle Origin Insertion Nerve Supply

Action

Pectoralis minor

Third, fourth, and fifth ribs

Medial border & superior surface of the coracoid process of scapula

Medial pectoral nerve from brachial plexus

Depresses point of shoulder; if the scapula is fixed, it elevates the ribs of origin

Serratus anterior

Upper eight ribs Along medial border and inferior angle of scapula

Long thoracic nerve

Draws the scapula forward around the thoracic wall; rotates scapula

Trapezius Occipital bone, ligamentum nuchae, spine of seventh cervical vertebra, spines of all thoracic vertebrae

Upper fibers into lateral third of clavicle; middle and lower fibers into medial border of acromion and upper lip of crest of spine of scapula

Spinal part of accessory nerve (motor) and C3 and 4 (sensory)

Upper fibers elevate the scapula; middle fibers pull scapula medially; lower fibers pull medial border of scapula downward

Latissimus dorsi

Iliac crest, lumbar fascia, spines of lower six thoracic vertebrae, lower three or four ribs, and inferior angle of scapula

Floor of bicipital groove of humerus

Thoracodorsal nerve

Extends, adducts, and medially rotates the arm

Levator scapulae

Transverse processes of first four cervical vertebrae

Medial border (dorsal aspect) of scapula (superior angle -spine root)

C3 and 4 and dorsal scapular nerve

Raises medial border of scapula

Rhomboideus minor

Ligamentum nuchae and spines of seventh cervical and first thoracic vertebrae

Medial border (dorsal aspect) of scapula (opposite to spine root)

Dorsal scapular nerve

Raises medial border of scapula upward and medially

Rhomboideus major

Second to fifth thoracic spines

Medial border (dorsal aspect) of scapula (spine root - inferior angle)

Dorsal scapular nerve

Raises medial border of scapula upward and medially

Deltoid Lower lip of crest of spine of scapula, lateral border of acromion, lateral one-third of clavicle

Middle of lateral surface of shaft of humerus

Axillary nerve

Abducts arm; anterior fibers flex and medially rotate arm; posterior fibers extend and laterally rotate arm

Supraspinatus

Medial two-thirds of supraspinous fossa including upper surface of the spine

Greater tuberosity of humerus; capsule of shoulder joint

Suprascapular nerve

Abducts arm and stabilizes shoulder joint

Infraspinatus

Medial two-thirds of infraspinous fossa including lower surface of the spine

Greater tuberosity of humerus; capsule of shoulder joint

Suprascapular nerve

Laterally rotates arm and stabilizes shoulder joint

Teres major Lower one-thirds of rough strip on dorsal aspect of the lateral border of scapula

Medial lip of bicipital groove of humerus

Lower subscapular nerve

Medially rotates and adducts arm and stabilizes shoulder joint

Teres minor Upper two-thirds of Greater tuberosity Axillary Laterally rotates arm

© Garaka Rabel – 2009

rough strip on dorsal surface along the lateral border of scapula

of humerus; capsule of shoulder joint

nerve and stabilizes shoulder joint

Subscapularis

Medial two-thirds of the subscapular fossa

Lesser tuberosity of humerus

Upper and lower subscapular nerves

Medially rotates arm and stabilizes shoulder joint

Long head of biceps brachii

Supraglenoid tubercle of scapula

Tuberosity of radius and bicipital aponeurosis into deep fascia of forearm

Musculocutaneous nerve

Supinator of forearm and flexor of elbow joint; weak flexor of shoulder joint

Short head of biceps brachii

Lateral part of the tip of the coracoid process of scapula

Tuberosity of radius and bicipital aponeurosis into deep fascia of forearm

Musculocutaneous nerve

Supinator of forearm and flexor of elbow joint; weak flexor of shoulder joint

Coracobrachialis

Medial part of the tip of the coracoid process of scapula

Medial aspect of shaft of humerus

Musculocutaneous nerve

Flexes arm and also process of weak adductor

Long head of triceps

Infraglenoid tubercle of scapula

Olecranon process of ulna

Radial nerve

Extensor of elbow joint

© Garaka Rabel – 2009