Shoulder Joint

Shoulder Complex The Glenohumeral joint is the most mobile joint in the body. The shoulder complex consists of the scapula, clavicle, sternum, humerus and rib cage. The joints involved in the shoulder complex are the sternoclavicular joint, acromioclavicular joint, glenohumeral joint and scapulothoracic articulation. The shoulder girdle is defined as the scapula and clavicle. The shoulder joint is the articulation between the scapula and humerus at the glenoid fossa.

Shoulder Complex Motions available at the shoulder joint are flexion, extension, hyperextension, abduction, adduction, medial and lateral rotation, horizontal abduction and horizontal adduction.

Muscles of the Shoulder Joint Deltoid Supraspinatus Pectoralis major Latissiumus dorsi Teres major Infraspinatus Teres minor Subscapularis Coracobrachialis Biceps brachii Triceps brachii (long head)

Anterior Deltoid

Anterior Deltoid O: Lateral third of clavicle I: Deltoid tuberosity A: Shoulder abduction, flexion, medial rotation and horizontal adduction 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 abduction, extension, hyperextension, lateral rotation, horizontal abduction N: Axillary nerve (C5, C6)

Supraspinatus

Supraspinatus O: Supraspinous fossa of scapula I: Greater tubercle of the humerus A: Shoulder abduction N: Suprascapular nerve (C5, C6) *Rotator Cuff Muscle*

Pectoralis Major

Pectoralis Major; Clavicular Portion O: Medial third of clavicle I: Lateral lip of bicipital groove of humerus A: Shoulder flexion (first 60 degrees) N: Lateral and medial pectoral nerve (C5, C6, C7, C8, T1)

Pectoralis Major; Sternal Portion O: Sternum, costal cartilage of first six ribs I: Lateral lip of bicipital groove of humerus A: Shoulder extension (first 60 degrees) N: Lateral and medial pectoral nerve (C5, C6, C7, C8, T1)

Pectoralis Major; Clavicular and Sternal Portions A: Shoulder adduction, medial rotation, and horizontal adduction N: Lateral and medial pectoral nerve (C5, C6, C7, C8, T1)

Latissimus Dorsi

Latissimus Dorsi O: Spinous processes of T7 through L5, posterior surface of sacrum, iliac crest and lower three ribs I: Medial lip of bicipital groove of humerus A: Shoulder extension, adduction, medial rotation, hyperextension N: Thoracodorsal nerve (C6, C7, C8)

Teres Major

Teres Major O: Axillary border of scapula near the inferior angle I: Crest below lesser tubercle next to the latissimus dorsi muscle attachment A: Shoulder extension, adduction and medial rotation N: Subscapular nerve (C5, C6)

Infraspinatus

Infraspinatus O: Infraspinous fossa of scapula I: Greater tubercle of humerus A: Shoulder lateral rotation, horixontal abduction N: Suprascapular nerve (C5, C6) *Rotator Cuff Muscle*

Teres Minor

Teres Minor O: Axillary border of scapula I: Greater tubercle of humerus A: Shoulder lateral rotation, horizontal abduction N: Axillary nerve (C5, C6) *Rotator Cuff Muscle*

Subscapularis

Subscapularis O: Subscapular fossa of the scapula I: Lesser tubercle of the humerus A: Shoulder medial rotation N: Subscapular nerve (C5, C6) *Rotator Cuff Muscle*

Coracobrachialis

Coracobrachialis O: Coracoid process of the scapula I: Medial surface of the humerus near the midpoint A: Stabilizes the shoulder joint N: Musculocutaneous nerve (C6, C7)