Origin: Clavicular head--anterior surface of medial half of clavicle; sternocostal head--anterior surface of sternum; first seven costal cartilages; sternal end of sixth rib; aponeurosis of external oblique

Insertion: Lateral lip of intertubercular sulcus of humerus

Innervation: Medial and lateral pectoral nerves: clavicular head (C5,C6); sternocostal head (C6, C7, C8, T1)

Function: Flexion, adduction, and medial rotation of arm at glenohumeral joint; clavicular head--flexion of extended arm; sternocostal head--extension of flexed arm

Origin: First rib at junction between rib and costal cartilage

Insertion: Groove on inferior surface of middle one-third of clavicle

Innervation: Nerve to subclavius (C5,C6)

Function: Pulls tip of shoulder down; pulls clavicle medially to stabilize sternoclavicular joint

Origin: Anterior surfaces and superior borders of ribs 3 to 5; and from deep fascia overlying the related intercostal spaces

Insertion: Coracoid process of scapula (medial border and upper surface)

Innervation: Media pectoral nerve (C5, C6, C7, C8, T1)

Function: Pulls tip of shoulder down; protracts scapula

Origin: Superior nuchal line, external occipital protuberance, medial margin of the ligamentum nuchae, spinous processes of CV2 to TX2 and the related supraspinous ligaments

Insertion: Superior edge of the crest of the spine of the scapula, acromion, posterior border of lateral one-third of clavicle

Innervation: Motor accessory nerve (XI).  Sensory (proprioception) anterior rami of C3 and C4

Function: Powerful elevator of the scapula; roates the scapula during abduction of humerus above horizontal; middle fibers retract scapula; lower fibers depress scapula

Origin: Inferior edge of the crest of the spine of the scapula, lateral margin of the acromion, anterior border of lateral one-third of clavicle

Insertion: Deltoid tuberosity of humerus

Innervation: Axillary nerve (C5, C6)

Function: Major abductor of arm (abducts arm beyond initial 15* done by supraspinatus); clavicular fibers assist in flexing the arm; posterior fibers assist in extending the arm

Origin: Transverse processes of C1 and C2 vertebrae and posterior tubercles of transverse processes of C3 and C4 vertebrae

Insertion: Posterior surface of medial border of scapula from superior angle to root of spine of the scapula

Innervation: Branches directly from anterior rami of C3 and C4 spinal nerves and by branches (C5) from the dorsal scapular nerve

Function: Elevates the scapula

Origin: lower end of ligamentum nuchae and spinous processes of C7 and T1 vertebrae

Insertion: Posterior surface of medial border of scapula at the root of the spine of the scapula

Innervation: Dorsal scapular nerve (C4, C5)

Function: Elevates and retracts the scapula

Origin: Spinous processes of T2-T5 vertebrae and intervening supraspinous ligaments

Insertion: Posterior surface of medial border of scapula from the root of the spine of the scapula to the inferior angle

Innervation: Dorsal scapular nerve (C4, C5)

Function:  Elevates and retracts the scapula

Origin: Medial two-thirds of the supraspinous fossa of the scapula and the deep fascia that covers the muscle

Insertion: Most superior facet on the greater tubercle of the humerus

Innervation: Suprascapular nerve (C5, C6)

Function: Rotator cuff muscle; initiation of abduction of arm to 15* at glenohumeral joint

Origin: Medial two-thirds of the infraspinous fossa of the scapula and the deep fascia that covers the muscle

Insertion:  middl facet on posterior surface of the greater tubercle of the humerus

Innervation:  Suprascapular nerve (C5, C6)

Function: Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint

Origin:  upper two-thirds of a flattened strip of bone on the posterior surface

Insertion: Inferior facet on the posterior surface of the greater tubercle of the humerus

Innervation: Axillary nerve (C5, C6)

Function: Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint

Origin: Elongate oval area on the posterior surface of the inferior angle of the scapula

Insertion: Medial lip of the intertubercular sulcus on the anterior surface of the humerus

Innervation: Inferior subscapular nerve (C5, C6, C7)

Function: Medial roation and extention of the arm at the glenohumeral joint

Origin:  Infraglenoid tubercle on scapula

Insertion: Common tendon of insertion with medial and lateral heads on the olecranon process of ulna

Innervation: Radial nerve (C6, C7, C8)

Function: Extension of the forearm at the elbow joint; accessory adductor and extensor of the arm at the glenohumeral joint

Origin: Lateral surfaces of upper 8-9 ribs and deep fascia overlying the related intercostal spaces

Insertion: Costal surface of medial border of scapula

Innervation: Long thoracic nerve (C5, C6, C7)

Function: Protraction and rotation of the scapula; keeps medial border and inferior angle of scapula opposed to thoracic wall