Shoulder Joint Anatomy: Surfaces, Ligaments, Bursa, Movements, and Stabilizers, Assignments of Nationality law

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Shoulder joint

Introduction

Also known as Glenohumeral joint

Type of joint – Ball & Socket type

Articular surfaces:

Head of Humerus

Glenoid cavity of Scapula

Ligaments

1.Capsular ligament & Synovial membrane

2.Glenohumeral ligament

3.Coracohumeral ligament

4.Transverse humeral ligament

Accessory ligaments:

Coracoacromial ligament

Coracoacromial arch

Synovial membrane

Lines the inner surface of capsule

and reflects from it to the

glenoid labrum and

humerus, thus forms the

synovial cavity

Extends as tubular sheath

to enclose long head of

biceps brachii tendon

It communicates with

Subscapular and

Infraspinatus bursae

Glenohumeral ligaments

Thickening of anterior part of

capsule forms the Glenohumeral

ligaments

Superior GHL

Middle GHL

Inferior GHL

Spiral GHL (rare)

Coracoacromial ligament

Ligament that extend

between coracoid process

to acromion process

Coracoacromial arch

• It is formed by coracoid process,

acromion process, and coracoacromial

ligament between them

• It protects the head of humerus from

above and prevents superior

displacement of the shoulder

• Relations:

 Supraspinatus muscle passes under

this arch

 Subacromial bursa lies between

acromion process superiorly and

tendon of supraspinatus inferiorly

Subacromia l

Relations

• Superiorly – Coracoacromial arch, Subacromial bursa,

Supraspinatus, Deltoid

• Inferiorly – Long head of Triceps, Axillary nerve, Posterior

circumflex humeral vessels, Teres major

• Anteriorly – Short head of biceps, Coracobrachialis,

Subscapularis, Subscapular bursa, Deltoid

• Posteriorly – Infraspinatus, Teres minor, Deltoid

Sagittal section of shoulder joint

Superior

relations

Nerve supply

Suprascapular nerve –branch from upper trunk of brachial

plexus

Axillary nerve – branch from posterior cord

Musculocutaneous nerve – branch from lateral cord

Movement

Movement take place in all axis

At transverse axis – Flexion & Extension

At vertical axis – Medial & Lateral rotation

At anteroposterior axis – Adduction & Abduction

Combination of all movements - Circumduction

Factors stabilizing the shoulder joint

Rotator cuff (Musculotendinous cuff) – formed by tendon

of Subscapularis, Supraspinatus, Infraspinatus and Teres

minor

These muscle grasp the head of humerus & pull it medially

towards glenoid cavity

Rotator cuff