Lecture 9

1. Lecture 9 The Forearm and Wrist

3. Anatomy Review Distal Radioulnar Joint • Uniaxial pivot joint • Pronation and supination • triangular fibrocartilage disc (TFC) Radiocarpal ( wrist) joint • condyloid joint • Radius articulates with the scaphoid, lunate and triquetrum • Flexion / extension and ulnar deviation/ radial deviation

4. TFC Disc • Acts as a cushion and shock absorber for the wrist • Major stabilizer of the distal radioulnar joint • Disc articulates with the lunate and the triquetral • Disc can be damages by forced extension and pronation

5. Intercarpal joints • Joints between the individual carpal bones of the proximal row • Scaphoid, lunate and triquetrium • Joints between the individual carpal bones of the distal row • Trapezium, trapezoid, capitate and hamate • Bound together by the intercarpal ligaments (dorsal, palmer and interosseous) • Allows for gliding movement

6. Midcarpal joint • Articulation between the proximal and distal rows ( except pisiform) • Dorsal and palmer ligaments • Greater movement at the mid carpal joint than at intercarpal joints because there is no interosseous ligament

7. Carpometatcarpal joint • At the thumb • saddle joint • flex/ ext , add/abd and rotation • 2-5 joints • plane synovial • gliding – flex/ext • dorsal and palmer ligaments

8. Intermetacarpal joints • small gliding , bound together by dorsal and palmer ligaments and interosseous ligaments • does not include thumb Metacarpophalageal joints • Condyloid joints ( knuckles) • Flex/ ext • Collateral ligaments , tight in flex – relaxed in ext • Palmer and dorsal ligaments • Deep transverse ligaments

9. At the thumb – Ulnar collateral ligament running from the 1st metacarpal to the proximal phalanx – crucial ligament ….. Interphangeal joints (PIP and DIP) • Uniaxial hinge joints • Flex/ext collateral and palmer ligaments

10. Functional Position of the hand • Wrist 20- 35 degrees extension • Ulnar deviation 10 – 15 degrees • Allows for complete flexion of the fingers as it relaxes the long extensor tendons

11. Movement at the wrist and hand • Pronation /Supination • Ulnar and radial deviation • Wrist flex/ext • Finger flex/ext • Finger abd/abb • Thumb flex/ext and abd/add • Muscles ??

12. Carpal tunnel • Runs across from the hook of hamate to the trapezium • Contains the median nerve and the tendons of the flexor digitorium profundas and superficialis

13. Special Tests

14. Cascade sign Metacarpal / phalanax ( fracture) • Watch fingers and knuckles during flexion • All fingers should converge towards the scaphoid • Positive test - If not even or does not cascade suspect a fracture of phalanx or metacarpal

15. Ligament stress test for IP and MP joints • Valgus and Varus • Testing collateral ligaments • Positive tests- more movement

16. Thumb UCL Ligament stress test • Thumb slightly extended apply a valgus stress to the MP joint • Positive test laxity and pain • Testing for the UCL or Gamekeeper’s or skier’s thumb

17. Axial loading (tapping) • phalanges • Examiner stabilizes athlete’s wrist • Grasps athletes finger or thumb and applies and axial load (or taps down long axial) • Positive test- pain • May indicate a fracture

18. Finkelstein test • Ext Pollicis brevis or abductor pollicis longus of thumb • Determines the presence of DeQuervains disease (tenosynovitis of the Ext Pollicis brevis or abductor pollicis longus of thumb) • Athlete makes a fist with thumb tucked in then ulnar deviates • Positive test – is pain over tendons (often pain is normal therefore must compare sides) • http://www.youtube.com/watch?v=RfyXClxY_E0&feature=PlayList&p=15F412838F0CB445&index=2&playnext=2&playnext_from=PL

19. Tinels sign at the wrist Median nerve • Examiner taps over the carpal tunnel • Positive test- is tingling into the distribution of the median nerve (thumb, index and middle finger and half of ring finger) • http://www.youtube.com/watch?v=XcDhqKRT2aU&feature=PlayList&p=15F412838F0CB445&index=4

20. Phalens test • Median nerve • Athlete flexes wrists together ( back to back) • Positive test- is tingling in the distribution of the median nerve • http://www.youtube.com/watch?v=RpGHYujo37o&feature=PlayList&p=15F412838F0CB445&index=3&playnext=3&playnext_from=PL

23. Muscle testing Flexers of the wrist • Flexor Carpi radialis, Flexor Carpi Ulnaris Flexor digitorum superficialis and Palmaris ( 15-20 % of population missing this one ) • Forearm is supinated , fingers in slight flexion • Resistance is applied to palmer surface and examiner pushes into extension • Positive test - pain and weakness

24. Extensors of the Wrist • Extensor Carpi Radialis longus and Brevis, Extensor Carpi Ulnaris, and Extensor digitorum longus • Forearm is pronated , fingers relaxed • Resistance is applied to the dorsum of the hand and examiner pushes into flexion • Positive test -pain and weakness

25. Fingers • Flexor digitorum profundus ( distal phalanx) and flexor digitorum superficialis ( middle phalanx) • Extensor digitorum longus • Thumb • Flexor pollicis longus and brevis • Extensor pollicis longus and brevis • Abductor pollicis longus and brevis • Adductor pollicis

26. Sport Specific Functional Tests • daily living should be assessed for manual dexterity and coordination. • Can they hook, pinch and gasp an object.