Anatomy of the shoulder joint

Anatomy of shoulder joint to help pain interventionists during procedures

1. THE SHOULDER JOINT: ANATOMY AND BIOMECHANICS PRESENTER: DR KAUSTAV BASU THAKUR MODERATOR: PROF. YUMNAM NANDABIR SINGH

2. INTRODUCTION THE SHOULDER COMPLEX C omplicated joint complex H igh degree of mobility compromising stability Involved in a variety of overhead activities Consists of Acromioclavicular Joint Sternoclavicular Joint Scapulothoracic joint Glenohumeral joint

3. Bony anatomy

4. Glenohumeral joint Most commonly dislocated joint Synovial multiaxial “ball & socket” joint Between head of humerus and glenoid cavity of scapula Accommodates one third of the humerus head Mobility gained at the expense of stability Stability depends on the surrounding muscular and soft tissue

5. GLENOID LABRUM Fibrocartilaginous rim Triangular in section Base attached to margin of the fossa Free inner edge as continuation of curve of glenoid cavity

6. GLENOID LABRUM contd.. FUNCTION Deepens the glenoid cavity Protects the edges of bone Acts as a lubricant

7. ARTICULATING SURFACES Reciprocally curved and ovoids The area of the humeral convexity exceeds that of the glenoid concavity Remaining articular surface in contact with the capsule and contact on glenoid fossa is more uniformly distributed over its entire articular surface A rticular surfaces covered by hyaline cartilage thickest centrally, thinner peripherally over the humerus and the reverse in the glenoid cavity

8. Articulating surfaces contd.

9. MOBILITY AND STABILITY Factors contributing to mobility Type of joint – Ball and socket Bony surfaces – Shallow glenoid cavity and large humeral head Laxity of the joint capsule

10. MOBILITY AND STABILITY contd Factors contributing to stability Rotator cuff muscles S urround the shoulder joint  A ttached to the tubercles of the humerus and joint capsule R esting tone act to ‘pull’ the humeral head into the glenoid cavity Glenoid labrum   Ligaments –  The ligaments act to reinforce the joint capsule and forms the coraco-acromial arch

11. Fibrous capsule Encircles entire glenohumeral joint Attachment : Scapular Humeral except Medially Anteriorly

12. Muscles supporting the capsule Superiorly  Supraspinatus Inferiorly  Long Head of Triceps Posteriorly  Tendons of Infraspinatus and Teres Minor Anteriorly  Tendon of Subscapularis

13. Openings in the fibrous capsule Posteriorly Not constant where a communication exists between joint and a bursal sac belonging to Infraspinatus muscle Anteriorly Below coracoid Process connection between synovial membrane of the joint and a bursa beneath the tendon of subscapularis muscle Between the 2 tuberosities passage of the biceps long head tendon

14. Synovial membrane Lines the inner surface of the fibrous capsule At humerus covers the anatomical neck upto margin of the articular surface of humerus head and medially a part of shaft below the epiphyseal line At glenoid goes to margin and covers both surfaces of glenoidal labrum Communicates with subscapular bursa or infraspinatus bursa

15. Bursa around gh joint Acromial: upper surface of acromian process Subacromial: inferiorly to the deltoid and acromion Subcoracoid bursa Infraspinatus bursa Subscapular bursa: between the subscapularis tendon and scapula

16. Ligaments of the shoulder joint Act as static stabilisers Three in numbers G lenohumeral (superior, middle and inferior ) Coraco humeral T ransverse humeral

17. GLEnohumeral ligament Three fibrous bands derived from thickening of the anterior part of fibrous capsule All 3 Converge upward and medially blend with glenoid labrum: SUPERIOR BAND : attached to the upper end of lesser tubercle MIDDLE BAND : attached to lower part of lesser tubercle INFERIOR BAND : lower part of anatomical neck of humerus

18. Transverse humeral ligament Broad band of fibrous tissues Connects the two lips of the upper part of intertubercular sulcus Acts as a retinaculum to keep the long tendon of biceps in position

19. Coraco -humeral ligament Broad thick Band Strengthens Upper part of Capsular Ligament Attachments Arises from outer border of coracoid process Blended with tendon of supraspinatus muscles United to capsule in greater part of its extend.

20. Vascular supply S upplied by branches from Anterior circumflex humeral artery P osterior circumflex humeral artery S uprascapular artery C ircumflex scapular artery

21. NERVE SUPPLY Glenohumeral joint Posterior cord of the brachial plexus Capsule S uprascapular nerve (posterior and superior parts) A xillary nerve ( antero inferior ) L ateral pectoral nerve ( antero superior)

22. Muscles around shoulder joint Primary role Movements of arm Dynamic stabilisation of glenohumeral joint There are 14 muscles divided into 4 functional groups Three heads deltoid (anterior, middle, posterior ) Four rotator cuff muscles and biceps muscle Two axio humeral muscles(pectoralis major and latismus dorsi ) and teres major Scapular muscle group –serratus anterior , trapezius, rhomboid major and minor and levator scapulae

23. Muscles in Relation to the Joint Above - Supraspinatus Below - Long head of Triceps Front - Subscapularis Behind - Infraspinatus and Teres Minor Deltoid is placed most externally and covers the articulation from its outer side, as well as in front and behind

24. Movements at the shoulder joint Osteokinematics Flexion Extension Abduction Adduction Internal rotation External rotation Horizontal abduction Horizontal adduction Circumduction

25. Flexion Plane of Motion: Sagittal Plane Axis of Motion: Transverse Axis through the center of the humeral head Muscles Involved: Pectoralis major Anterior Fibres of Deltoid Coracobrachialis Biceps (when the forearm is flexed ) Range of Motion 0 – 170 degrees

26. extension Plane of Motion: Sagittal Plane Axis of Motion: Transverse Axis through the center of the humeral head Muscles Involve: Latissimus dorsi Teres major Posterior fibers of Deltoid Triceps (When forearm is extended ) Range of Motion 0 – 60 degrees

27. abduction Plane of Motion: Frontal Plane Axis of Motion: Sagittal axis through the centre of the humeral head Muscles Involve: Deltoid Supraspinatus Range of Motion Total : 0 – 170 degrees

28. adduction Plane of Motion: Frontal Plane Axis of Motion: Sagittal axis through the centre of the humeral head Muscles Involve: Subscapularis Pectoralis Major Latissimus dorsi Teres major

29. Internal rotation Plane of Motion: Transverse Plane Axis of Motion: Vertical axis through the centre of humeral head Muscles Involve: Subscapularis Pectoralis Major Latissimus dorsi Teres major Range of Motion: 0-70º a s the arm at 90º of shoulder abduction and 90º elbow flexion 0-60° if abduction not possible

30. External rotation Plane of Motion: Transverse Plane Axis of Motion: Vertical axis through the center of humeral head Muscles Involve: Infraspinatus Teres Minor Range of Motion 0-90º as the arm at 90º of shoulder abduction and 90º elbow flexion 0-80° if abduction not possible

31. circumduction A combination of flexion, abduction, extension, and adduction or in the reverse sequence. Occurs in a cone whose apex is the head of humerus glenohumeral flexion  abduction  extension  adduction glenohumeral extension  abduction  flexion  adduction

32. Scapulohumeral rhythm The first 30 degrees A t gleno-humeral joint with slight movement of clavicle From 30 to 120 degrees 1/3 of movement coming from scapula rotating on thorax From 120 to 180 degrees M ovement mainly scapulo-thoracic Sterno -clavicular joint participates in movements close to the trunk A cromioclavicular joint moves in the last 60 degrees of abduction

33. ROTATOR CUFF Group of four muscles to hold the head of humerus into the glenoid fossa They are Supraspinatus Infraspinatus Teres Minor Subscapularis

34. Function of rotator cuff I mportant in movements and maintaining joint stability Abduction: Concavity compression R otator cuff muscles also perform Abduction I nternal rotation E xternal rotation of the shoulder

35. THANK YOU