This document describes the origin, insertion, innervation and action of several muscles around the shoulder and arm. It lists the pectoralis minor, serratus anterior, and trapezius muscles, detailing their origin on the ribs or spine, insertion on the scapula or clavicle, nerve supply and primary actions of depressing or rotating the scapula. It also outlines several muscles that originate on the scapula, such as the deltoid, supraspinatus and infraspinatus, and insert on the humerus, acting to abduct, rotate or stabilize the shoulder joint.

1. Muscle Origin Insertion Nerve Supply Action
Pectoralis minor Third, fourth, and fifth ribs Medial border & superior Medial pectoral Depresses point of
surface of the coracoid nerve from shoulder; if the scapula is
process of scapula brachial plexus fixed, it elevates the ribs of
origin
Serratus anterior Upper eight ribs Along medial border and Long thoracic Draws the scapula forward
inferior angle of scapula nerve around the thoracic wall;
rotates scapula
Trapezius Occipital bone, ligamentum Upper fibers into lateral Spinal part of Upper fibers elevate the
nuchae, spine of seventh third of clavicle; middle accessory nerve scapula; middle fibers pull
cervical vertebra, spines of and lower fibers into (motor) and C3 scapula medially; lower
all thoracic vertebrae medial border of acromion and 4 (sensory) fibers pull medial border of
and upper lip of crest of scapula downward
spine of scapula
Latissimus dorsi Iliac crest, lumbar fascia, Floor of bicipital groove of Thoracodorsal Extends, adducts, and
spines of lower six thoracic humerus nerve medially rotates the arm
vertebrae, lower three or
four ribs, and inferior angle
of scapula
Levator scapulae Transverse processes of first Medial border (dorsal C3 and 4 and Raises medial border of
four cervical vertebrae aspect) of scapula (superior dorsal scapular scapula
angle -spine root) nerve
Rhomboideus Ligamentum nuchae and Medial border (dorsal Dorsal scapular Raises medial border of
minor spines of seventh cervical aspect) of scapula nerve scapula upward and
and first thoracic vertebrae (opposite to spine root) medially
Rhomboideus Second to fifth thoracic Medial border (dorsal Dorsal scapular Raises medial border of
major spines aspect) of scapula nerve scapula upward and
(spine root - inferior angle) medially
Deltoid Lower lip of crest of spine Middle of lateral surface of Axillary nerve Abducts arm; anterior
of scapula,lateral border of shaft of humerus fibers flex and medially
acromion, lateral one-third rotate arm; posterior fibers
of clavicle extend and laterally rotate
arm
Supraspinatus Medial two-thirds Greater tuberosity of Suprascapular Abducts arm and stabilizes
ofsupraspinous fossa humerus; capsule of nerve shoulder joint
including upper surface of shoulder joint
the spine
Infraspinatus Medial two-thirds Greater tuberosity of Suprascapular Laterally rotates arm and
ofinfraspinous fossa humerus; capsule of nerve stabilizes shoulder joint
including lower surface of shoulder joint
the spine
Teres major Lower one-thirds of rough Medial lip of bicipital Lower Medially rotates and
strip on dorsal aspect of the groove of humerus subscapular adducts arm and stabilizes
lateral border of scapula nerve shoulder joint
Teres minor Upper two-thirds of rough Greater tuberosity of Axillary nerve Laterally rotates arm and
strip on dorsal surface along humerus; capsule of stabilizes shoulder joint
the lateral border of scapula shoulder joint
Subscapularis Medial two-thirds of the Lesser tuberosity of Upper and Medially rotates arm and
subscapular fossa humerus lower stabilizes shoulder joint
subscapular
nerves
Long head of Supraglenoid tubercle of Tuberosity of radius and Musculocutane Supinator of forearm and
biceps brachii scapula bicipital aponeurosis into ous nerve flexor of elbow joint; weak
deep fascia of forearm flexor of shoulder joint
Short head of Lateral part of the tip of the Tuberosity of radius and Musculocutane Supinator of forearm and
biceps brachii coracoid process of scapula bicipital aponeurosis into ous nerve flexor of elbow joint; weak
deep fascia of forearm flexor of shoulder joint
Coracobrachialis Medial part of the tip of the Medial aspect of shaft of Musculocutane Flexes arm and also process
coracoid process of scapula humerus ous nerve of weak adductor
© Garaka Rabel – 2009

2. Long head of Infraglenoid tubercle of Olecranon process of ulna Radial nerve Extensor of elbow joint
triceps scapula
© Garaka Rabel – 2009