Anatomy of Shoulder Joint

In this article, we will discuss about the Anatomy of the Shoulder Joint. So, let’s gets started.

Anatomy

Joint type– Synovial Ball and Socket Joint, Diarthrosis, and multiaxial joint

Degree of freedom– 3

Bones involved– Glenoid cavity of Scapula and Head of Humerus

Joint Spaces– Glenohumeral space (4-5 mm), Subacromial space (9-10 mm), and Axillary space.

Muscles surrounding the joint– Biceps brachii, and rotator cuff musculature (which involves subscapularis, supraspinatus, infraspinatus, and teres minor)

Joint capsule– Articular capsule of the humerus

Bursa– Subacromial-subdeltoid bursa present between the joint capsule and deltoid muscle. subacromial bursa present between the joint capsule and the acromion process, subcoracoid bursa present between the joint capsule and coracoid process, coracobrachial bursa present between the coracobrachialis muscle and the subscapularis muscle, subscapular bursa present between the joint capsule and subscapularis muscle, and supra-acromial bursa.

Ligaments– Capsular ligament, superior, middle, and inferior glenohumeral ligament, coracohumeral ligament, coraco-acromial ligament, and transverse humeral ligament.

Nerve supply– Subscapular, left pectoral, and axillary nerve.

Artery supply– Anterior and posterior circumflex humeral arteries. suprascapular artery, and scapular circumflex artery.

Shoulder joint movements (muscles involved along with axis and planes)

1. Movement- Flexion

Muscles involved- Pectoralis major, anterior fibres of the deltoid, supraspinatus, and coracobrachialis.

Axis and Plane- Frontal axis and Sagittal plane

2. Movement- Extension

Muscles involved- Lattisimus dorsi, posterior fibres of the deltoid, and triceps brachii

Axis and Plane- Frontal axis and Sagittal plane

3. Movement- Abduction

Muscles involved- Deltoid, supraspinatus, trapezius, and serratus anterior

Axis and Plane- Sagittal axis and Frontal plane

4. Movement- Adduction

Muscles involved- Pectoralis major, lattisimus dorsi, teres major, and subscapularis

Axis and Plane- Frontal plane and Sagittal axis

5. Movement- Internal rotation

Muscles involved- Deltoid (anterior fibres), teres major, pectoralis major, lattisimus dorsi, and subscapularis

Axis and Plane- Vertical axis and transverse plane

6. Movement- Lateral rotation

Muscles involved- Deltoid (posterior fibres), infraspinatus, and teres minor

Axis and Plane- Vertical axis and transverse plane

7. Movement- Horizontal abduction

Muscles involved- Subscapularis, supraspinatus, and deltoid (posterior fibres)

Axis and Plane- Vertical axis and transverse plane

8. Movement- Horizontal adduction

Muscles involved- Pectoralis major, biceps brachii, and deltoid (anterior fibres)

Axis and Plane- Vertical axis and transverse plane

9. Movement- Diagonal adduction

Muscles involved- Pectoralis major, deltoid (anterior fibres), and biceps brachii

Axis and Plane- Diagonal axis and diagonal plane

10. Movement- Diagonal abduction

Muscles involved- Subscapularis, deltoid, and supraspinatus

Axis and Plane- Diagonal axis and diagonal plane

11. Circumduction- Combination of flexion, extension, adduction, and abduction.