Anatomy of shoulder joint

Anatomy of shoulder joint by Dr Bipul Borthakur

1. ANATOMY OF SHOULDER JOINT DR BIPUL BORTHAKUR PROFESSOR & HOD DEPARTMENT OF ORTHOPAEDICS,SMCH

2. Shoulder joint Shoulder joint is formed by articulation of the scapula (glenoid cavity) and head of the humerus Glenohumeral joint

3. Type of joint It is a synovial joint Polyaxial Ball and socket variety.

4. Proximal articular surface Glenoid fossa of scapula : Pyriform in shape Surface area and concavity of the glenoid fossa is increased by glenoid labrum Glenoid labrum – fibro cartilaginous ribbon like structure Covered with hyaline cartilage.

5. Distal articular surface The head of humerus : Hemispherical in shape Covered with hyaline cartilage

6. Shoulder joint – weak point Glenoid fossa is too small and shallow to hold the head of humerus The head is four times the size of glenoid cavity Structurally it is a weak joint

7. Stability of the joint : Ligaments True ligament : Capsule Accessory ligaments : All the accessory ligaments attach either to lesser or greater tubercles of humerus Glenohumeral ligaments Transverse humeral ligament Coraco-humeral ligament Secondary socket/ ligament ( Coracoacromial arch) Glenoid labrum

8. True ligament : Capsule Loose fibrous covering Inner surface lined with synovial membrane Proximal attachments : Margins of glenoid fossa Distal attachments : Anatomical neck of humerus

9. Accessory ligaments Glenohumeral ligaments : Three : Superior band Middle band Inferior band Seen on inner side of anterior part of capsule

10. Glenohumeral ligaments cont.. Proximal attachment : (Glenoid ) All 3 bands attached to upper end of glenoid fossa Distal attachment : (Humerus) U pper band : Top of lesser tubercle Middle band : Lesser tubercle deep to the tendon of subscapularis Lower band : Shaft just below the lesser tubercle

11. Transverse humeral ligament It is broad band which passes between the humeral tubercles It is attached superior to the epiphyseal line Long head of biceps tendon passes out deep to this ligament

12. Coraco-humeral ligament Origin - Lateral margin of root of coracoid process Insertion - greater tuberosity of humerus

13. Coracoacromial ligament Triangular band Base : Attached to lateral margin of coracoid process Apex : Attached to tip of acromion C oracoid process, ligament and acromion together form – Coracoacromial arch (which forms secondary socket for the joint)

14. Glenoid labrum Fibro cartilaginous ribbon like structure Attached to margins of the glenoid cavity Increases the depth of the glenoid cavity. Lined by hyaline cartilage

15. Rotator cuff Laxity and weakness of joint is compensated by rotator cuff Tendons of rotator cuff : Supraspinatus Infraspinatus Teres minor Subscapularis

16. Rotator cuff cont.. Expansions from these tendons fuse with capsule Strengthens the capsule all around ( except inferiorly ) Injury to rotator cuff result in recurrent dislocation .

17. Relations of shoulder joint Muscles Bursae Vessels and nerves

18. Relations of shoulder joint: Muscles Anteriorly : Subscapularis Coracobrachialis Short head of biceps Deltoid Posteriorly : Infraspinatus Teres minor Deltoid

19. Cont … Superiorly : Long head of biceps inside the capsule Supraspinatus outside the capsule Inferiorly : Long head of triceps Deltoid covers superiorly, anteriorly, posteriorly and laterally.

20. Bursae related to shoulder joint Subacromial bursa : L ies between deltoid muscle and capsule Does not communicate with joint Extends between supraspinatus and acromion and coracoacromial arch Longest bursa in the body

21. Blood supply Arterial supply : Anterior circumflex humeral artery Posterior circumflex humeral artery Suprascapular artery Circumflex scapular branch of subscapular artery Venous drainage : Corresponding veins

22. Nerve supply Lateral pectoral nerve Suprascapular nerve Axillary nerve (posterior division)

23. Movements at shoulder joint Flexion and extension Adduction and abduction Medial and lateral rotation Circumduction

24. Flexion and extension : Transverse Axis Flexors of shoulder joint : Pectoralis major (Clavicular part) Deltoid (anterior fibres ) Coracobrachialis and assisted by biceps Extensors of shoulder joint : Deltoid (posterior fibres ) Teres major Latissimus dorsi and pectoralis major ( sternocostal part)

25. Abduction and Adduction : Antero-posterior axis Abductors of shoulder joint : Supraspinatus :0-30 Deltoid(middle fibres ) : 0-90 Serratus anterior and trapezius : 90-180 Adductors of shoulder joint : Pectoralis major Latissimus dorsi Teres major Coracobrachialis Biceps (short head )

26. Medial and lateral rotation : Longitudinal axis Medial rotation : Pectoralis major Deltoid (anterior fibres ) Latissimus dorsi Teres major and subscapularis Lateral rotation : Infraspinatus Deltoid (posterior fibres ) and teres minor

27. Circumduction Combination of 3 axis Combination of all the muscles around shoulder

28. Anterior glenohumeral dislocation Trauma to the upper extremity with the shoulder in abduction, extension, and external rotation. BANKART lesion – Avulsion of anteroinferior labrum off the glenoid rim. It may be associated with a glenoid rim fracture (Bony Bankart ) Hills-Sachs lesion : A posterolateral head defect is caused by an impression fracture on the glenoid rim.

29. Inferior glenohumeral dislocation( Luxatio Erecta ) Most common in elderly individuals. It results from a hyperabduction force causing impringement of the humerus on the acromion which leaves the humeral head out inferiorly Patient typically present in salute fashion Humeral head is typically palpable on the lateral chest wall and axilla.

30. Rotator cuff disorders Impingement : The muscle most commonly involved is supraspinatus as it passes beneath the acromion and the acromioclavicular ligament. This space beneath which the supraspinatus tendon passes is of fixed dimensions Swelling of this muscle causes excessive fluid within the subacromial/ subdeltoid bursa or subacromial body spurs may produce significant impingement when arm is abducted

31. Cont.. Tendinopathy : The blood supply to the supraspinatus tendon is relatively poor. Repeated trauma in certain circumstances makes the tendon susceptible to degenerative changes which may result in calcium deposition producing extreme pain

32. Subacromial bursitis It is inflammation of the bursa that separates the superior surface of the supraspinatus tendon from the overlying coraco-acromial ligament, acromion and coracoid and from the deep surface of the deltoid muscle.

33. THANK YOU