Lecture 9 The Forearm and Wrist

Distal Radioulnar Joint 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

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

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

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

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

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

Interphangeal joints (PIP and DIP) 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

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

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 ??

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

Special Tests

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

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

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

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

Ext Pollicis brevis or abductor pollicis longus of thumb 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

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

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

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

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

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

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