Anatomy of shoulder joint

1.INTRODUCTION
Shoulder joint is formed by scapula and clavicle (which is also called as shoulder girdle)and proximal humerus.
2.BONES OF SHOULDER JOINT
3.Joints of the Shoulder Complex
Glenohumeral
Acromioclavicular
Sternoclavicular
Scapulothoracic
4.Muscles of the Shoulder
5.Gateways to the Posterior Scapular Region
6. Movements

1. ANATOMY OF SHOULDER JOINT PRESENTOR:DR.VISHAL PUSHKARNA (FIRST YEAR PG ORTHOPAeDICS ) MODERATOR: Dr.VAMSHI ASST.PROFESSOR,PIMS V.P

2. INTRODUCTION Shoulder joint is formed by scapula and clavicle ( which is also called as shoulder girdle )and proximal humerus . It has the greatest range of motion of any joint in the body . Due to wide range of movement it is also most unstable joint compared to other joints of the body.However a series of complex ligaments and muscle keep it in joint V.P

3. BONES OF SHOULDER JOINT Articulates at one end with the sternum (chest bone) and with the acromion of the scapula at the other.( Roof of the shoulder ) Forms the front portion of the shoulder girdle and is palpable along its entire length with a gentle S-shaped contour. Clavicle V.P

4. It is a flat, triangular bone that lies over the back of the upper ribs. It serves as an attachment for some of the muscles and tendons of the arm, neck, chest and back and aids in the movements of the arm and shoulder. Anterior View Posterior View Scapula V.P

5. The proximal humerus consists of the head, neck, greater and lesser tubercles, and the shaft. The neck lies between the head and the greater and lesser tubercles. The greater and lesser tubercles are prominent landmarks on the humerus and serve as attachment sites for the rotator cuff muscles. Proximal Humerus V.P

6. OSSIFICATION CENTRES V.P

7. CLAVICLE It’s the 1 st bone to ossify . It has no medullary cavity. It occurs by intramembranous ossification. Secondary ossification centres via endochondral . Medial epiphysis ossifies at 12-19yrs and fuses at 22 to 25yrs. Lateral epiphysis ossifies and fuses at 19yrs. V.P

8. SCAPULA Body and spine[posterior] ossify at birth Coracoid process[anterior]- atavastic epiphysis. centre at 1yr,base at 10yrs. Acromian [lateral projection]-fuses by 22yrs via 2- 5centres form at puberty Glenoid -upper 1/4 th ossify at 10yrs lower3/4 th appear at puberty ,fuse by 22yrs V.P

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10. PROXIMAL HUMERUS Humeral head-ossifies at 6mths Greater tuberosity -ossifies at 1 to 3yrs Lesser tuberosity -ossifies at 4 to 5yrs. Physis close at 14-17yrs girls and 16-18yrs boys. V.P

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12. Joints of the Shoulder Complex Glenohumeral Acromioclavicular Sternoclavicular Scapulothoracic V.P

13. Glenohumeral The glenohumeral joint is the most mobile joint in the body. The ‘socket’ ( glenoidfossa ) is very shallow, and doesn’t hold on to the ‘ball’ ( humeral head ) very well Joint type: ball and socket synovial joint It is therefore up to a group of muscles (called the Rotator Cuff - further discussed in the ‘Muscles’ section) to ‘hold the ball in the socket’, providing stability and some movement V.P

14. The glenoid labrum also helps to improve the stability of the shoulder. The glenoid labrum is a cartilage ring around the glenoidfossa . This labrum makes the ‘socket’ deeper, giving it a larger and deeper contact surface to articulate with the head of the humerus . The articular capsule is a fibrous bag of tissue, fused with local ligaments, which provides a sealed sac around the glenohumeral joint. V.P

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16. Glenohumeral ligaments provide anterior stability to the glenohumeral joint Superior (SGHL) Middle (MGHL) Inferior (IGHL) V.P

17. Glenohumeral Joint Superior GH Ligament Resists inferior translation in rest or adducted arm Well-developed in 50% V.P

18. Glenohumeral Joint Middle GH Ligament Great variability in proximal attachment & morphology Absent in 30% Resists inferior translation in ABD & ER Restrains anterior translation (45 ° ABD) V.P

19. Glenohumeral Joint Inferior GH Ligament 3 components ( A,P,Ax ) Resists inferior, anterior, & posterior translation V.P

20. CORACOHUMERAL LIGAMENT Arises from lateral base of coracoid process and extends onto both tuberosities . It forms roof of bicipital tendon sheath and strengtens capsule anteriorly . Importance-resists inferior and posterior translation. TRANSVERSE HUMERAL LIGAMENT Bridges upper part of bicipital groove through which long head of biceps passes down. V.P

21. Joint type: plane or sliding synovial joint Bones involved in the articulation: Acromion of the Scapula Distal end of the Clavicle Movements: only small translations Anterior/Posterior glide Superior/Inferior tilt Rotation Acromioclavicular Joint V.P

22. Acromioclavicular ligament – acts to secure the acromion and clavicle and provides a complete capsule around the joint. Coracoclavicular ligaments – anchor the lateral aspect of the clavicle to the coracoid process of scapula. It consists of two small ligaments holding the scapula laterally, these are: Trapeziod - attaches to the trapezoid line on the inferior surface of the clavicle Conoid - attaches to the conoid tubercle of the clavicle V.P

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24. Sternoclavicular Joint V.P

25. Joint type: saddle synovial joint Sternoclavicular Joint Bones involved in the articulation : Manubrium of the Sternum Proximal end of the Clavicle Movements: Anterior/Posterior glide Superior/Inferior tilt Rotation V.P

26. Take note of the: Sternoclavicular ligament Costoclavicular and Interclavicular ligaments Sternoclavicular Joint V.P

27. Scapulothoracic Joint V.P

28. Joint type: not a ‘true’ joint, but known as a ‘pseudo’ joint Bones involved in the articulation : Anterior surface of the Scapula Ribcage of the Thorax Scapulothoracic Joint V.P

29. Movements: Protraction and retraction Elevation and depression Anterior tilt and posterior tilt Upward rotation and downward rotation As there is minimal bony contact, it is up to the muscles attaching to the scapula and thorax to stabilise and control movement at this articulation There is no joint capsule or synovial fluid Scapulothoracic Joint V.P

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33. The muscles of the shoulder girdle provide vital stability for the mobile shoulder joint Muscles of the Shoulder V.P

34. Muscles - Trapezius Name Origin Insertion Action Innervation Trapezius (upper, middle & lower) External occipital protuberance, ligamentumnuchae & spinous processes of C7-T12 Lateral 1/3of clavicle, acromion & superior edge of the crest of the spine of the scapula Scapular stabilisation Upper – scap elevation Middle – scap retraction Lower - scap retraction Accessory nerv (XI) C3, 4 V.P

35. Muscles - Deltoid Name Origin Insertion Action Innervation Deltoid (anterior, middle & posterior parts) Lateral 1/3 of clavicle, acromion process + spine of scapula Deltoid tuberosity Shoulder abduction Axillary nerve V.P

36. Muscles – Levator Scapulae Levator scapulae Transverse processes of C1-4 Medial scapula Elevation + retraction of scapula Dorsal scapular nerve Name Origin Insertion Action Innervation V.P

37. Muscles – Rhomboid Minor Rhomboid minor Spinous processes C7-T1 Medial border of scapula near spine of scapula Scapular retraction + medial rotation Dorsal scapular nerve Name Origin Insertion Action Innervation V.P

38. Muscles – Rhomboid Major Rhomboid major Spinous processes T2-5 Medial border of scapula Scap retraction + medial rotation Dorsal scapular nerve Name Origin Insertion Action Innervation V.P

39. Muscles - Pectoralis Major Pectoralis major Sternal + clavicular attachments Intertubercular groove (lateral lip) Adduction + IR Medial & lateral pectoral nerves Name Origin Insertion Action Innervation V.P

40. Muscles – Pectoralis Minor Pectoralis minor Outer surfaces ribs 3, 4 & 5 Coracoid process Medial rotaion of scapula Medial pectoral nerve Name Origin Insertion Action Innervation V.P

41. Muscles – Teres Major Name Origin Insertion Action Innervation Teres major Dorsal scapula near inferior angle Intertubercular groove Adduction + IR Lower subscapular nerve V.P

42. Muscles - LatissimusDorsi Latissimus dorsi Thoracolumbar fascia, T6-S5 spinous processes, + iliac crest Lower 3-4 ribs, inferior angle of scapula + intertubercular groove Shoulder E from flexed position, sh adduction + IR Thoracodorsal nerve Name Origin Insertion Action Innervation V.P

43. Muscles – Serratus Anterior Serratus anterior Upper 8-9 ribs Medial border of scapula Scapular protraction Long thoracic nerve Name Origin Insertion Action Innervation V.P

44. Muscles - Subclavius Subclavius Subclavian groove on clavicle 1 st rib Stabilise clavicle Nerve to subclavius C5,6 Name Origin Insertion Action Innervation V.P

45. Muscles – Biceps Brachii Biceps brachii – long head - short head Supraglenoid tubercle of scapula + glenoidlabrum ( lh ) Coracoid process ( sh ) Radial tuberosity Shoulder flexion, elbow flexion & forearm supination Musculocutaneous nerve Name Origin Insertion Action Innervation V.P

46. Muscles – Triceps Brachii Triceps brachii long head lateral head medial head Infraglenoid tubercle (long) Above spiral groove (lateral) Distal to spiral groove (medial) Olecranon process Long head: sh adduction All: elbow E Radial nerve Name Origin Insertion Action Innervation V.P

47. The rotator cuff muscles ( supraspinatus , infraspinatus , teres minor and subscapularis ) help to stabilize the humeral head in the glenoidfossa , plus have roles in shoulder rotation Rotator Cuff Muscles V.P

48. Muscles - Supraspinatus Name Origin Insertion Action Innervation Supraspinatus Medial 2/3 supraspinousfossa Greater tuberosity Shabd + dynamic stability Suprascapular nerve V.P

49. Muscles - Infraspinatus Infraspinatus Medial 2/3 infraspinousfossa Greater tuberosity Sh ER + dynamic stability Suprascapular nerve Name Origin Insertion Action Innervation V.P

50. Muscles – Teres Minor Teres minor Upper 2/3 lateral border of scap Greater tuberosity Sh ER +/- adduction, + dynamic stability Axillary nerve Name Origin Insertion Action Innervation V.P

51. Muscles - Subscapularis Subscapularis Medial 2/3 subscapularfossa Lesser tuberosity Sh IR +/- adduction Upper & lower subscapular nerves Name Origin Insertion Action Innervation V.P

52. BLOOD SUPPLY V.P

53. Anterior circumflex humeral vessels Posterior circumflex humeral vessels Suprascapular vessels Subscapular vessels V.P

54. NERVE SUPPLY V.P

55. Axillary nerve Suprascapular nerve Musculocutaneous nerve V.P

56. Gateways to the Posterior Scapular Region Suprascapular Foramen Quadrangular Space Triangular Space Triangular Interval V.P

57. Gateways to the Posterior Scapular Region Suprascapular Foramen It is formed by suprascapular notch of scapula and the superior transverse scapular ligament,which converts the notch into a foramen. The suprascapular nerve passes trough the suorascapular foramen V.P

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60. Gateways to the Posterior Scapular Region Quadrangular Space Its boundaries are formed by: The inferior margin of the teres minor Surgical neck of humerus The superior margin of the teres major Lateral margin of the long head of triceps brachii . Axillary nerve and posterior circumflex humeral artery and vein pass trough this space V.P

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63. Gateways to the Posterior Scapular Region Triangular Space Its boundaries are formed by The medial margin of the long head of triceps brachii The superior margin of the teres major The inferior margins of the teres minor The circumflex scapular artery and vein pass trough this space V.P

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66. Gateways to the Posterior Scapular Region Triangular Interval Boundaries are formed by The lateral margin of the long head of triceps brachii The shaft of the humerus The inferior margin of the teres major Radial nerve,profunda brachii artery and associated veins pass trough it V.P

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69. Movements V.P

70. The muscles and joints of the shoulder allow it to move through a remarkable range of motion , Arm flexion(0-135*) Arm extention (45°-60*) Arm abduction (0-180*) Arm adduction Medial rotation of the arm (90°) Lateral rotation of the arm(0-90*) circumduction (this is a combination of the above movement) V.P

71. MOVEMENTS MAIN MUSCLE ACCESSORY MUSCLE FLEXION 0-135* PECTORALISMAJOR( clavicular part) DELTOID ant fibres Coracobrachialis Biceps short head EXTENSION 45-60* DELTOID post fibres LATISSMUS DORSI Teres major Triceps long head P major[ sternocoastal head] V.P

72. ADDUCTION PECTORALIS MAJOR LATISSMUS DORSI BICEPS long head TRICEPS short head Teres major coracobrachialis ABDUCTION SUPRASPINATUS[0-15*] DELTOID[15*-90*] SERRATUS ANTERIOR[90*-180*] TRAPEZOID upper,lower fibres [90-180] MOVEMENTS MAIN MUSCLE ACCESSORY MUSCLE V.P

73. MEDIAL ROTATION [INTERNAL] 90* PECTORALIS MAJOR DELTOID ant fibres LATISSMUS DORSI TERES MAJOR subscapularis LATERAL ROTATION [EXTERNAL] 70*-90* DELTOID posterior fibres INFRASPINATUS TERES MINOR MOVEMENTS MAIN MUSCLE ACCESSORY MUSCLE V.P

74. CIRCUMDUCTION Combination of different movements, results in hand moving along a circle . V.P

75. THANK YOU V.P