Chapter 7 - Upper Extremity Injuries

1. Chapter 7 - Upper Extremity Injuries Impair peoples’ ability to manipulate the environment. Upper extremity design for motion not for the support of large loads

2. Shoulder Anatomy • Shoulder complex: • Shoulder girdle: scapula and clavicle • Shoulder joint joint • Sternoclavicular joint: • Modified Ball & Socket • disk • Acromioclavicular joint • AC ligaments • Coracoclavicular joint • Glenohumeral joint: • Scapulothoracic joint

3. Shoulder Anatomy • Glenohumeral Joint • Most mobile joint • Shallow joint cavity • Glenoid labrum • Glenohumeral ligaments • Coracohumeral ligament • Muscular support • Rotator cuff muscles

4. Shoulder Anatomy • Rotator cuff • subscapularis • infraspinatus • supraspinatus • teres minor • Primary source of stability to the shoulder

5. Shoulder Anatomy

6. Shoulder Injuries • AC sprain or separated shoulder • Indirect or direct forces • direct force to acromion with shoulder in adducted position • fall on a outstretched arm • traction to arm • Classification • Type I-III • Type IV > rare • severe forces

7. Shoulder Injuries • Shoulder instability • poor joint cavity • poor ligament • musculature • Intracapsular pressure • Concavity compression • scapulohumeral balance

8. Shoulder Injuries • Anterior Luxation • mostly anterior when arm is abducted, extended and ext. rotated • posterior forces • Posterior luxation • same mechanism reverse • Inferior luxation

9. Shoulder Injuries • Impingement • glenohumeral joint: abduction • supraspinatus and bursae • Categories • Under 35 year: sports or jobs with overhead movement • Older: degeneration • Microtrauma-instability-subluxation-aggravation

10. Shoulder Injuries • Rotator cuff impingements • Extrinsic: structural factors • hook acromion • hypertrophy of supraspinatus • Intrinsic • inflammation of the tissue • Mechanism • work of sports requiring overhead movements • Wheelchair (abductor dominance)

11. Shoulder Injuries • Rupture Rotator cuff • Chain of events: • inflammation • microtears • partial or total rupture • movement adaptations • Supraspinatus rupture most common • Eccentric actions • acceleration phase • decceleratiom phase

12. Shoulder Injuries • Upper arm • two compartments • anterior • posterior • Humeral fractures • 7% of fractures • Direct or indirect • Low & high energy • falls, car crashes, direct loading, violent muscle contraction (throwing)

13. Shoulder Injuries • Biceps tendon injuries • tenosynovitis (repetition) • dislocation (medial) • abduction/ext. rotation • falls outstretched arm • lateral impact • hyperextension • anterior GH dislocation • bicipital grove angulation • rupture: tissue degeneration • SLAP

14. Elbow Anatomy • Hinge joint • Ligament support • MCL:valgus loading • LCL: varus loading • Annular ligament • Muscles • Flexors: biceps, brachialis and brachioradialis • Extensor: Triceps & anconeus

15. Elbow Injuries • Epicondylitis: repeated loading causing microtrauma and tissue degeneration leading to inflammation and tissue weakness • Lateral epicondylitis • tennis players 30-50 years old, poor stroke mechanics, excessive muscle contraction • Overuse of extensor mechanics, pinching and grasping

16. Elbow Injuries • Medial epicondylitis • excessive loading forehand and serve • Advanced players • Wrist motions

17. Elbow Injuries • Valgus Extension Loading • large varus torque • Mechanism • elbow extension • huge internal rotation torque transmitted to elbow

18. Elbow Injuries • Dislocations • more stable, less incidence of dislocation • Axial force to extended or hyper • Avulsion of collateral ligaments

19. Elbow Injuries • Fractures • humeral • Ulnar • olecranon:impact or hyperextension • Radial • axial loading of radius from a fall or dislocation

20. Forearm Anatomy • Two bones • radius & ulna • Two compartments of muscles • anterior: flexor-pronator • posterior:extensor-supinator • Proximal radioulnar joint • Distal radioulnar joint

21. Forearm injuries • Diaphyseal fractures of ulna & Radius • Galeazi: distal 1/3 radius, outstretched arm, blow to dorsum of wrist • Nightstick • Montegia lesion: classification for ulnar fractures • Distal radius: Colles etc.

22. Forearm injuries • Ulnar variance: relative length of ulna and radius • Determined • genetics • elbow pathology • mechanical loading • Ulnar variance in gymnast-premature closure of radial growth plate • Gymnastic: huge loads to the wrist- cartilage degeneration/fractures

23. Wrist & Hand Anatomy • Wrist joints • distal radio ulnar • radiocarpal • intercarpal • Hand joints • CM: • MP: condyloid • IP: hinge

24. Wrist & Hand Anatomy • Strong ligaments • Muscles • control wrist & finger motion • carpal tunnels • Flexor & extensor retinacula

25. Wrist & Hand Injuries • Carpal tunnel (CTS) • result from repetitive stress to tissue • 64% of work injuries • Compressive neuropathy • Wrist flexion/ext and finger movements • Risk factors • exertion • repetitive stress • posture • localized contact • cold

26. Wrist & Hand Injuries • Carpal fractures • compressive loads to hyperextended wrist • hyper flexion • rotation loading against a fixed wrist • Scaphoid • 60-70% • Lunate

27. Wrist & Hand Injuries • Thumb: essential to prehension • Sprain: skiers thumb • fall with thumb in abducted position • tensile loads on MCL • Hyperextension • Bennets fracture (fighting) • Bowler’s thumb: ulnar digital nerve trauma • tingling, sensitivity

28. Wrist & Hand Injuries • Metacarpal & phalangeal injuries • Fractures • Boxers • Dislocations