Shoulder Girdle Muscles (OIAI)

Pectoralis major Origin

Clavicular head - medial half of clavicle

Sternal head - sternum and costal cartilages of first 6 ribs

Pectoralis Major and Latissimus Dorsi Insertion

intertubercular groove of humerus

Pectoralis Major action

flexes, adducts, and medially rotates humerus

Pectoralis Major and Minor innervation

Lateral and Medial Pectoral nerves

pectoralis minor origin

ribs 3-5 near the costal cartilages

pectoralis minor insertion

coracoid process of scapula

pectoralis minor action

Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall

coracobrachialis origin

Tip of coracoid process of scapula

coracobrachialis insertion

middle third of medial surface of humerus

coracobrachialis action

flexes and adducts arm

coracobrachialis and biceps brachii innervation

Musculocutaneous nerve (C5, C6, C7)

Anterior deltoid origin

lateral 1/3 of clavicle

anterior, middle, and posterior deltoid insertion

deltoid tuberosity of humerus

anterior deltoid action

shoulder flexion

teres minor, anterior, middle, and posterior deltoid innervation

Axillary nerve (C5, C6)

middle deltoid origin

lateral 1/3 of clavicle, acromion, spine of scapula

middle deltoid action

shoulder abduction

posterior deltoid origin

acromion and spine of scapula

posterior deltoid action

shoulder extension and lateral rotation

Biceps Brachii origin

short head: coracoid process

long head: supraglenoid tubercle

Biceps brachi insertion

radial tuberosity

biceps brachii action

flexes elbow and supinates forearm

triceps brachii origin

Long head: infraglenoid tubercle of scapula

Lateral Head: posterior surface of humerus and superior to radial groove

Medial Head: posterior surface of the humerus inferior to the radial groove

triceps brachii insertion

olecranon process of ulna

triceps brachii action

extends elbow

triceps brachii innervation

Radial nerve (C6, C7, C8)

infraspinatus origin

infraspinous fossa of scapula

infraspinatus insertion

Middle facet of greater tubercle of humerus

infraspinatus action

lateral rotation of arm

infraspinatus and supraspinatus innervation

Suprascapular nerve (C5, C6)

teres minor origin

middle 1/3 of lateral border of the scapula

teres minor insertion

Inferior facet of greater tubercle of humerus

teres minor action

laterally rotates arm

subscapularis origin

subscapular fossa

subscapularis insertion

lesser tubercle of humerus

subscapularis action

medially rotates arm

subscapularis innervation

Upper and lower subscapular nerves (C5, C6, C7)

supraspinatus origin

supraspinous fossa of scapula

supraspinatus insertion

Superior facet of greater tubercle of humerus

supraspinatus action

shoulder abduction and slight lateral rotation

teres major origin

Posterior surface of inferior angle of scapula

teres major insertion

Medial lip of intertubercular groove of humerus

teres major action

adducts and medially rotates arm

teres major innervation

lower subscapular nerve

rhomboid major origin

spinous processes of T2-T5

rhomboid major insertion

Medial border of the scapula between the spine of the scapula and inferior angle

rhomboid major action

retraction and downward rotation of scapula

rhomboid major and minor innervation

Dorsal scapular nerve (C4, C5)

rhomboid minor origin

spinous processes of C7-T1

rhomboid minor insertion

The medial end of the scapular spine

rhomboid minor action

retraction and downward rotation of scapula

levator scapulae origin

Posterior tubercles of transverse processes of C1-C4

levator scapulae insertion

medial border of scapula superior to the root of the spine of the scapula

levator scapulae action

elevation and downward rotation of scapula

levator scapulae innervation

Cervical nerves (C3, C4) and Dorsal scapular nerve (C4, C5)

upper trapezius origin

medial 1/3 of the superior nuchal line, external occipital protuberance, nuchal ligament

Upper Trapezius Insertion

lateral 1/3 of clavicle

Upper Trapezius Action

Scapular elevation and upward rotation

upper, middle, and lower trapezius innervation

spinal accessory nerve (CN XI) and C3-C4 spinal nerves

middle trapezius origin

Spinous processes and supraspinous ligaments of C7-T3

Middle Trapezius Insertion

Medial acromial margin and superior border of the scapular spine

Middle Trapezius Action

scapular retraction and upward rotation

lower trapezius origin

spinous processes and supraspinous ligaments of vertebrae T6-T12

Lower Trapezius Insertion

lateral apex of the medial end of scapular spine

Lower Trapezius Action

scapular depression and upward rotation

latissimus dorsi origin

Spinous processes of inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs

latissimus dorsi action

extends, adducts, and medially rotates humerus

latissimus dorsi innervation

Thoracodorsal nerve (C6-C8)