The Shoulder Anatomy.pptx

This presentation describes the anatomy of the shoulder. It discusses all the bones that make up the shoulder joint and also the muscles that are embedded in those bones. It further discusses the blood supply and innervation to those muscles.

1. THE SHOULDER COMPLEX DR. JOSEPH KAMARA

2. INTRODUCTION  THE SHOULDER COMPLEX  Complicated joint complex  High 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. ARTICUL ATING 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  Articular surfaces covered by hyaline cartilage  thickest centrally, thinner peripherally over the humerus and the reverse in the glenoid cavity

8. ARTICUL ATING SURFACES CONTD.

9. MOBILITY AND STABILIT Y 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 STABILIT Y CONTD Factors contributing to stability  Rotator cuff muscles  Surround the shoulder joint  Attached 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  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  Posteriorly  Not constant where a communication exists between joint and a bursal sac belonging to Infraspinatus muscle

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 1. Acromial: upper surface of acromian process 2. Subacromial: inferiorly to the deltoid and acromion 3. Subcoracoid bursa 4. Infraspinatus bursa 5. Subscapular bursa: between the subscapularis tendon and scapula

16. LIGAMENTS OF THE SHOULDER JOINT  Act as static stabilisers  Three in numbers  Glenohumeral (superior, middle and inferior)  Coraco humeral  Transverse 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  Supplied by branches from  Anterior circumflex humeral artery  Posterior circumflex humeral artery  Suprascapular artery  Circumflex scapular artery

21. NERVE SUPPLY  Glenohumeral joint  Posterior cord of the brachial plexus  Capsule  Suprascapular nerve (posterior and superior parts)  Axillary nerve (antero inferior)  Lateral pectoral nerve (antero superior)

22. MUSCLES AROUND SHOULDER JOINT  Primary role a. Movements of arm b. Dynamic stabilisation of glenohumeral joint  There are 14 muscles divided into 4 functional groups 1. Three heads deltoid (anterior, middle, posterior) 2. Four rotator cuff muscles and biceps muscle 3. Two axio humeral muscles(pectoralis major and latismus dorsi) and teres major 4. Scapular muscle group – serratus anterior , trapezius, rhomboid major and minor and levator scapulae

23. MUSCLES IN REL ATION 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  – 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  – 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 : – 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 as 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  At 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  Movement mainly scapulo-thoracic  Sterno-clavicular joint participates in movements close to the trunk  Acromioclavicular 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 Teres Minor Infraspinatus Subscapularis

34. FUNCTION OF ROTATOR CUFF  Important in movements and maintaining joint stability  Abduction: Concavity compression  Rotator cuff muscles also perform  Abduction  Internal rotation  External rotation of the shoulder

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