Lecture 9

The Forearm and Wrist

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 DiscActs as a cushion and shock absorber for

the wrist Major stabilizer of the distal radioulnar

joint Disc articulates with the lunate and the

triquetralDisc 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

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 jointsValgus and VarusTesting collateral ligamentsPositive 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

Finkelstein testExt 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.