Shoulder Muscles- Origins, Insertions, Actions and Inervations of Shoulder Muscles

Muscle	O,I,A,N
Anterior Deltoid	O:Lateral third of the clavicle I:Deltoid tuberosity A:Shoulder abd, flexion, IR, horizontal add N:Axillary nerve (C5,C6)
Middle Deltoid	O:Acromion process I:Deltoid tuberosity A:Shoulder abduction N:Axillary nerve (C5,C6)
Posterior Deltoid	O:Spine of scapula I:Deltoid tuberosity A:Shoulder abd, extension, hyperextension, ER, horizontal abd N:Axillary nerve (C5,C6)
Supraspinatus	O:Supraspinous fossa of scapula I:Greater tubercle of humerus A:Shoulder abduction N:Suprascapular nerve (C5,C6)
Pectoralis Major, Clavicular Portion	O:Medial third of clavicle I:Lateral lip of bicepital groove of humerus A:Shoulder flexion-first 60 degrees
Pectoralis Major, Sternal Portion	O:Sternum, costal cartilage of first six ribs I:Lateral lip of bicepital groove of humerus A:Shoulder extension-first 60 degrees (from 180-120)
Pectoralis Major, Sternal and Clavicular Portions	O:Medial third of clavicle and sternum and costal cartilage of first six ribs I:Lateral lip of bicepital groove of humerus A:Shoulder add, IR, and horizontal add N:Lateral and medial pectoral nerve (C5,C6,C7,C8,T1)
Latissimus Dorsi	O:Spinous processes of T7-L5, posterior surface of sacrum, illiac crest, and lower three ribs I:Medial lip of biciptal groove of humerus A:Shoulder extension, add, IR, hyperextension N:Thoracodorsal nerve(C6,C7,C8)
Teres Major	O:Axillary border of scapula near inferior angle I:Crest below lesser tubercle next to the latissimus dorsi muscle attachment A:Shoulder extension, adduction, and IR N:Subscapular nerve (C5,C6)
Infraspinatus	O:Infraspinous fossa of scapula I:Greater tubercle of humerus A:Shoulder ER, horizontal abduction N:Suprascapular nerve (C5,C6)
Teres Minor	O:Axillary border of scapula I:Greater tubercle of humerus A:Shoulder ER, horizontal abduction N:Axillary nerve (C5,C6)
Subscapularis	O:Subscapular fossa of scapula I:Lesser tubercle of humerus A:IR N:Subscapular nerve(C5,C6)
Coracobrachialis	O:Coracoid process of scapula I:Medial surface of humerus near midpoint A:Stabilizes shoulder joint N:Musculocutaneous nerve (C6,C7)
Upper Trapezius	O:Occipital bone, nuchal ligament on cervial spinous processes I:Outer third of clavicle, acromion process A:Scapular elevation and upward rotation N:Spinal accessory (cranial nerve XI)
Middle Trapezius	O:Spinous processes of C7 through T3 I:Scapular spine A:Scapular retraction N:Spinal accesory (cranial nerve XI)
Lower Trapezius	O:Spinous processes of middle and lower thoracic vertebrae T4-T12 I:Base of the scapular spine A:Scapular depression and upward rotation N:Spinal accesory (cranial nerve XI)
Levator Scapula	O:Transverse processes of the first four cervical vertebrae,C1-C4 I:Vertebral border of scapula between superior angle and spine A:Scapular elevation and downward rotation N:Third and fourth cervical nerves and dorsal scapular nerve (C5)
Rhomboids	O:Spinous processes of C7 through T5 I:Vertebral border of scapula between the spine and inferior angle A:Scapular retraction, elevation, and downward rotation N:Dorsal scapular nerve (C5)
Serratus Anterior	O:Lateral surface of the upper eight ribs I:Vertebral border of the scapula, anterior surface A:Scapular protraction and upward rotation N:Long thoracic nerve (C5,C6,C7)
Pectoralis Minor	O:Anterior surface of third through fifth ribs I:Coracoid process of the scapula A:Scapular depression, protraction, downward rotation, and tilt N:Medial pectoral nerve (C8,T1)