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Glenohumeral joint
The right shoulder and Glenohumeral joint
Latin	articulatio humeri
Gray's	subject #82 315
MeSH	Glenohumeral+Joint

The glenohumeral joint, commonly known as the shoulder joint, is a multiaxial synovial ball and socket joint and involves articulation between the glenoid fossa of the scapula (shoulder blade) and the head of the humerus (upper arm bone).

Contents 1 Movements 2 Capsule 3 Ligaments 4 Pathology 5 Additional images 6 Notes 7 References 8 External links

[edit] Movements

The glenoid fossa is shallow and contains the glenoid labrum which deepens it and aids in stability. With 120 degrees of unassisted flexion, the glenohumeral joint is the most mobile joint in the body.

Scapulohumeral rhythm helps to achieve further range of movement. The Scapulohumeral rhythm is the movement of the scapula across the thoracic cage in relation to the humerus. This movement can be compromised by anything that changes then position of the scapula. This could be an imbalance in the muscles that hold the scapula in place which are the upper and lower trapezium. This imbalance could cause a forward head carriage which in turn can affect the range of movements of the shoulder.

The rotator cuff muscles of the shoulder produce a high tensile force, and help to pull the head of the humerus into the glenoid fossa.

Movements of the shoulder joint^[1]

Movement	Muscles	Origin	Insertion
Flexion	Anterior fibers of deltoid	Clavicle	Middle of lateral surface of shaft of humerus
	Clavicular part of pectoralis major	Clavicle	Lateral lip of bicipital groove of humerus
	Long head of biceps brachii	Supraglenoid tubercle of scapula	Tuberosity of radius, Deep fascia of forearm
	Short head of biceps brachii	Coracoid process of scapula
	Coracobrachialis	Coracoid process	Medial aspect of shaft of humerus
Extension	Posterior fibers of deltoid	Spine of scapula	Middle of lateral surface of shaft of humerus
	Latissimus dorsi	Iliac crest, lumbar fascia, spines of lower six thoracic vertebrae, lower 3-4 ribs, inferior angle of scapula	Floor of bicipital groove of humerus
	Teres major	Lateral border of scapula	Medial lip of bicipital groove of humerus
Abduction	Middle fibers of deltoid	Acromion process of scapula	Middle of lateral surface of shaft of humerus
	Supraspinatus	Supraspinous fossa of scapula	Greater tuberosity of humerus
Adduction	Sternal part of pectoralis major	Sternum, upper six costal cartilages	Lateral lip of bicipital groove of humerus
	Latissimus dorsi	Iliac crest, lumbar fascia, spines of lower six thoracic vertebrae, lower 3-4 ribs, inferior angle of scapula	Floor of bicipital groove of humerus
	Teres major	Lower third of lateral border of scapula	Medial lip of bicipital groove of humerus
	Teres minor	Upper two thirds of lateral border of scapula	Greater tuberosity of humerus
Lateral rotation	Infraspinatus	Infraspinous fossa of scapula	Greater tuberosity of humerus
	Teres minor	Upper two thirds of lateral border of scapula	Greater tuberosity of humerus
	Posterior fibers of deltoid	Spine of scapula	Middle of lateral surface of shaft of humerus
Medial rotation	Subscapularis	Subscapular fossa	Lesser tuberosity of humerus
	Latissimus dorsi	Iliac crest, lumbar fascia, spines of lower 3-4 ribs, inferior angle of scapula	Floor of bicipital groove of humerus
	Teres major	Lower third of lateral border of scapula	Medial lip of bicipital groove of humerus
	Anterior fibers of deltoid	Clavicle	Middle of lateral surface of shaft of humerus

[edit] Capsule

The glenohumeral joint has a loose capsule that is lax inferiorly and therefore is at risk of dislocation inferiorly. The long head of the biceps brachii muscle travels inside the capsule to attach to the supraglenoid tubercle of the scapula.

Because the tendon is inside the capsule, it requires a synovial tendon sheath to minimize friction.

A number of bursae in the capsule aid mobility. Namely, they are the subdeltoid bursa (between the joint capsule and deltoid muscle), subcoracoid bursa (between joint capsule and coracoid process of scapula), coracobrachial bursa (between subscapularis muscle and tendon of coracobrachialis muscle), subacromial bursa (between joint capsule and acromion of scapula) and the subscapular bursa (between joint capsule and tendon of subscapularis muscle, also known as subtendinous bursa of subscapularis muscle). The bursa are formed by the synovial membrane of the joint capsule. An inferior pouching of the joint capsule between teres minor and subscapularis is known as the axillary recess.

It is important to note that the shoulder joint is a muscle dependent joint as it lacks strong ligaments.

[edit] Ligaments

• Superior, middle and inferior glenohumeral ligaments
• Coracohumeral ligament
• Transverse humeral ligament

[edit] Pathology

The capsule can become inflamed and stiff, with abnormal bands of tissue (adhesions) growing between the joint surfaces, causing pain and restricting movement of the shoulder, a condition known as frozen shoulder or adhesive capsulitis.

[edit] Additional images

Diagram of the human shoulder joint

The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula.

[edit] Notes

[edit] References

• Snell, Richard S.. Clinical Anatomy by Systems. Lippincott Williams & Wilkins.  (CD-ROM/PDF)

[edit] External links

• Overview at brown.edu
• Overview at ouhsc.edu
• SUNY Figs 10:03-12
• Diagram at yess.uk.com

v • d • e Joints and ligaments of upper limbs (TA A03.5, GA 3.313) Shoulder Sternoclavicular Anterior sternoclavicular · Posterior sternoclavicular · Interclavicular · Costoclavicular Acromioclavicular Syndesmoses: Coracoacromial · Superior transverse scapular · Inferior transverse of scapula Synovial: Acromioclavicular · Coracoclavicular (trapezoid, conoid) Glenohumeral Coracohumeral · Glenohumeral (superior, middle, and inferior) · Transverse humeral · Glenoid labrum Elbow Humeroradial Radial collateral Humeroulnar Ulnar collateral Proximal radioulnar Anular · Oblique cord Forearm Distal radioulnar Volar radioulnar · Dorsal radioulnar · Interosseous membrane of forearm Joints of hand Wrist/radiocarpal Palmar radiocarpal · Dorsal radiocarpal · Palmar ulnocarpal · Ulnar collateral · Radial collateral Intercarpal, midcarpal Pisohamate · Scapholunate Carpometacarpal Dorsal carpometacarpal · Palmar carpometacarpal (pisometacarpal) Intermetacarpal Deep transverse metacarpal · Superficial transverse metacarpal Metacarpophalangeal Palmar · Collateral Interphalangeal Palmar · Collateral Other Carpal tunnel · Ulnar canal