Chapter 5: The Upper Extremity: The Shoulder Region

1. Chapter 5:The Upper Extremity:The Shoulder Region KINESIOLOGY Scientific Basis of Human Motion, 11th edition Hamilton, Weimar & Luttgens Presentation Created by TK Koesterer, Ph.D., ATC Humboldt State University Revised by Hamilton & Weimar

2. Objectives 1. Name, locate, & describe the structure & ligamentous reinforcements of the joints. 2. Name & demonstrate movements possible. 3. Name & locate muscles & muscle groups, and name their primary actions. 4. Analyze the fundamental movements with respect to joint & muscle actions. 5. Describe common injuries.

3. Acromioclavicular (AC) Joint • Articulation of acromion & distal end of clavicle. • Acromioclavicular ligament strengthens joint superiorly. • Aponeurosis of trapezius & deltoid strengthen joint posteriorly. • Coracoclavicular ligament further stabilizes joint. Fig 5.1

4. Sternoclavicular (SC) Joint • Proximal clavicle articulates with sternum and cartilage of 1st rib. • Capsule thickened by anterior & posterior sternoclavicular ligaments. Fig 5.2

5. Sternoclavicular (SC) Joint • Great importance because it is the only bony connection between the humerus and axial skeleton. • Permits limited motion of the clavicle. • Is partially responsible for movements of the scapula. • Clavicle movements at the SC joint: elevation & depression, protraction & retraction, and forward & backward rotation.

6. Movements of the Shoulder Girdle Fig 5.3 a & b Elevation Depression Abduction (Protraction) Adduction (Retraction)

7. Movements of the Shoulder Girdle Fig 5.3 c & d Upward rotation Downward rotation Anterior tilt Posterior tilt

8. MUSCLES OF THE SHOULDER GIRDLE • Location: • Anterior • Pectoralis minor, Serratus anterior, Subclavius • Posterior • Levator scapulae, Rhomboids, Trapezius

9. Pectoralis Minor Function: • Movements of scapula: downward rotation, anterior tilt, depression. • Lifting effect on ribs in forced inspiration and posture. Fig 5.4

10. Serratus Anterior Function: • Abduct (protract) scapula. • With trapezius, upward rotation of scapula. • Active in reaching and pushing. Fig 5.4

11. Subclavius Function: • Protect and stabilize sternoclavicular joint. • Depress scapula. Fig 5.4

12. Levator Scapulae Function: • Elevation and downward rotation of scapula. Fig 5.5

13. Rhomboids, Major and Minor Function: • Downward rotation, adduction (retraction), & elevation of scapula. • With trapezius for maintenance of good posture. Fig 5.5

14. Trapezius Function: I. Elevation II. Elevation, upward rotation, adduction III. Adduction IV. Upward rotation, depression, adduction Fig 5.6

15. GLENOHUMERAL (Shoulder) JOINTStructure • Articulation of spherical head of humerus with small, shallow, somewhat pear-shaped glenoid fossa of scapula. Fig 5.7

16. GLENOHUMERAL (Shoulder) JOINTStructure • Glenoid labrum deepens the fossa and cushion against impact of humeral head in forceful movements. Fig 5.8

17. Ligamentous Reinforcements • Coracohumeral • Glenohumeral • Coracoacromial Fig 5.9

18. Muscular Reinforcements • Above: supraspinatus & long head of biceps. • Below: long head of triceps. • Front: subscapularis, pectoralis major, & teres major. • Behind: infraspinatus & teres minor.

19. Movements of the Shoulder Joint • Flexion / Extension • Hyperextension • Circumduction • Abduction / Adduction • Horizontal • Diagonal • Internal / External Rotation External rotation Internal rotation

20. MUSCLE OF THE SHOULDER JOINT • Location: • Anterior: Pectoralis major, coracobrachialis, subscapularis, biceps brachii. • Posterior: Infraspinatus, teres minor. • Superior: Deltoid, supraspinatus. • Inferior: Latissimus dorsi, teres major, long head of triceps brachii.

21. Pectoralis Major Function: Clavicular portion – flexion, horizontal adduction, and internal rotation of humerus. Sternal portion – downward & forward movements of arm, & internal rotation with adduction. Fig 5.11

22. Coracobrachialis Function: • Horizontal adduction • Acts like a guy wire to stabilize the shoulder joint. Fig 5.12

23. Biceps Brachii Function: • Flexion at the elbow & supination of forearm. • Horizontal adduction at shoulder. • Short head sometimes active in adduction & internal rotation. Fig 5.12

24. Deltoid Function: • Powerful abductor of humerus. • Middle – Abduction • Anterior – all forward movements & internal rotation of humerus. Fig 5.14

25. Subscapularis Function: • Internal rotation of humerus as part of the rotator cuff. • Contributes to stability of shoulder joint. Fig 5.13a

26. Supraspinatus Function: • Acts together with deltoid in abduction of the arm. • Also acts in flexion & horizontal extension. • Contributes to stability of shoulder joint. • Part of the rotator cuff. Fig 5.13b

27. Infraspinatus and Teres Minor Function: • External rotation as part of the rotator cuff. • With subscapularis depresses head of humerus. • Contributes to stability of shoulder joint. Fig 5.13b

28. Latissimus Dorsi Function: • Extension & adduction of arm, internal rotation. Fig 5.14

29. Teres Major Function: • Internal rotation, extension, & adduction of the arm. Fig 5.15

30. Triceps Brachii Function: • Long head assists in adduction, extension, and hyperextension of the humerus. Fig 5.15

31. JOINT AND MUSCULAR ANALYSIS OF THE FUNDAMENTAL MOVEMENTS OF THE ARM ON THE TRUNK • Movements of the arm on the trunk involve the cooperative action of the shoulder girdle • Acromioclavicular joints • Sternoclavicular joints and the shoulder (glenohumeral) joint.

32. Movements in the Frontal Plane • Shoulder Joint - Abduction • Deltoid & supraspinaus • Shoulder Girdle: Upward rotation of scapula. • Serratus anterior; trapezius II & IV Fig 5.16

33. Movements in the Frontal Plane • Shoulder Joint - Adduction • Latissimus dorsi, teres major, pectoralis major (sternal), & post. deltoid. • Shoulder Girdle: reduction of upward rotation. • Rhomboids & pectoralis minor. Fig 5.17

34. Movements in the Sagittal Plane • Shoulder Joint - Flexion • Anterior deltoid & pectoralis major (clavicular). • Shoulder Girdle: Upward rotation of scapula • Serratus anterior & trapezius II & IV. Fig 5.18

35. Movements in the Sagittal Plane • Shoulder Joint - Extension • Pectoralis major (sternal), teres major, latissimus dorsi, post. Deltoid. • Shoulder Girdle: Reduction of upward rotation of scapula • Relaxation of agonists • Against resistance - trapezius IV, rhomboids, pect. minor. Fig 5.19

36. Movements in the Sagittal Plane • Shoulder Joint - Hyperextension • Teres major, latissimus dorsi, post. Deltoid. • Shoulder Girdle: Anterior tilt of scapula • Pectoralis minor. Fig 5.20

37. Movements in the Horizontal Plane • Shoulder Joint - External Rotation • Infraspinatus & teres mino.r • Shoulder Girdle: Adduction of scapula • Rhomboids & trapezius III. Fig 5.22a

38. Movements in the Horizontal Plane • Shoulder Joint - Internal Rotation • Subscapularis, teres major, latissimus dorsi, ant. deltoid, pectoralis major. • Shoulder Girdle: Abduction of scapula • Serratus anterior & pectoralis minor. Fig 5.22b

39. Movements in the Horizontal Plane • Shoulder Joint - Horizontal Adduction • Pectoralis major, ant. deltoid, & coracobrachialis. • Shoulder Girdle: Abduction of scapula • Serratus anterior & pectoralis minor • Shoulder Joint – Horizontal Abduction • Post. deltoid, post middle deltoid, infraspiantus, teres minor, long head of biceps. • Shoulder Girdle: Adduction of scapula • Rhomboids & trapezius III.

40. Diagonal Movements • Diagonal forward-downward and slightly inward movement of the arm. Fig 5.10 Fig 5.23

41. COMMON INJURIES OF THE SHOULDER REGION Acromioclavicular Sprain • AC joint forced beyond normal ROM. • Downward blow to outer end of shoulder. • Fall on outstretched hand. • Damage consists of tearing or severe stretching of AC ligaments.

42. COMMON INJURIES OF THE SHOULDER REGION Fracture of The Clavicle • Clavicle fractures have causes similar to AC sprain: • Downward blow to outer end of shoulder. • Fall on outstretched hand. • May indicate injury by supporting injured arm. • Head may be tilted toward injured side with face turned to opposite side.

43. COMMON INJURIES OF THE SHOULDER REGION Dislocation of the Shoulder • May be forward, downward, or posterior. • Most likely when arm is forcefully abducted and laterally rotated. • May occur by a blow to top of shoulder . • Head of humerus is forced out of the glenoid fossa. • Arm held out from side in a position of slight abduction and lateral rotation. • Loss of normal rounded contour of deltoid muscle.

44. COMMON INJURIES OF THE SHOULDER REGION Rotator Cuff Tears • Supraspinatus (supraspinatus tendon) most often injured. • Nature of injury depends on arm kinematics. • Caused by overuse, falls, or violent, fast arm motion.

45. COMMON INJURIES OF THE SHOULDER REGION Shoulder Impingement • Soft tissue superior to humeral head pressed against acromion process. • Due to overuse, inflammation, trapped bursa, degeneration with aging. • Will cause pain and inflammation in shoulder.

46. Chapter 5:The Upper Extremity:The Shoulder Region