Anatomy of wrist joint

Anatomy of wrist joint by Dr Bipul Borthakur

1. DR BIPUL BORTHAKUR PROFESSOR & HOD DEPT OF ORTHOPAEDICS, SMCH ANATOMY OF WRIST JOINT

2. LEARNING OBJECTIVES ARTICULAR SURFACES LIGAMENTS MOVEMENTS BLOOD SUPPLY NERVE SUPPLY MECHANISM OF INJURY RADIOLOGICAL EVALUATION APPLIED ANATOMY SCAPHOID FRACTURE LUNATE FRACTURE PERILUNATE DISLOCATION OTHERS

3. WRIST JOINT Wrist joint is a synovial joint of ellipsoid type. Also called radio carpal joint Carpal fracture accounts for 18% all wrist fracture Carpal fracture associated with 7% of distal radius fracture

4. Normal anatomic relationship Radial inclination : ranges from 13 to 30 % Radial length : ranges from 8 to 18 mm Palmar tilt : ranges from 0 to 28 degree

5. ARTICULAR SURFACES WRIST JOINT IS FORMED BY: DISTALLY: The proximal row of the carpel bone(except pisiform ) PROXIMALLY: The distal end of radius and articular disc CARPAL BONES: Proximal row: scaphoid , lunate , triquetrum and pisiform (lateral to medial) Distal row: trapezium, trapezoid, capitate and hamate (lateral to medial)

6. SURFACE MARKINGS OF WRIST JOINT The position of wrist joint can be indicated by drawing a curve line, with its convexity upward , between the styloid process of radius and ulna The summit of convexity is about 1 cm , above the centre of straight line joining the two processes

7. LIGAMENTS There are four ligaments in the wrist joint: Palmar radiocarpal : it is found on the palmar ( anterior) surface of hand. It provides stability of joint. Besides it ensure that the hand follows the forearm during pronation Dorsal radiocarpal : it is found on posterior surfaces of hand . It also provides joint stability

8. Ulnar collateral: Runs from the ulnar styloid proces to the triquetrum and pisiform . It prevent excessive lateral joint displacement Radial collateral : Runs from radial styloid process to the scaphoid and trapezium. It also prevent excessive lateral displacement

9. Movements of the wrist joint All the movements are performed by the musles of forearm Flexion : Produced by flexor carpi ulnaris , flexor carpi radialis , and flexor digitorium superficialis Extension : Produced by extensor carpi radialis longus and brevis and extensor carpi ulnaris Adduction : Extensor carpi ulnaris and flexor carpi ulnaris abduction : Produced by the abductor pollicis longus flexor carpi radialis and extensor carpi radialis longus and brevis

10. Blood supply of wrist joint The wrist received blood from branches of the deep and superficial palmar arches, which are derived from the ulnar and radial arteries

11. Nerve supply of wrist joint Wrist is innervated by: Anterior interosseous branch : Branch of median nerve Posterior interosseus branch : Branch of radial nerve Deep & dorsal branches : Branch of ulnar nerve

12. MECHANISM OF INJURY The most common mechanism of carpal bones injury in hand is fall onto outstretched, due to axial compressive force with the wrist in hyperextension The volar ligaments are placed under tension with compression and shear forces applied dorsally ,especially when the wrist is extended beyond the physiological limits Excessive ulnar deviation and intercarpal supination result in a predictable pattern of perilunate injury Direct injuries like crush injuries

13. CLINICAL EVALUATION The clinical evaluation of individual carpal bones are variable , but in general most consistent sign of carpel injury are well localized tenderness Gross deformity may be present , ranging from displacement of carpus to prominance of individual carpal bones

14. RADIOLOGICAL EVALUATION Radiography: Posteroanterior , oblique and lateral x rays are each taken with the wrist in the neutral position. Gilula lines (3 smooth radiographic arc) are distorted in ligamentous instability Arthrography &arthroscopy: Can assist in the diagnosis of carpal ligament injuries. Computed tomography (CT): Helps in evaluating carpel fractures, malunion , nonunion and bone loss Magnetic resonance imaging(MRI) : It is sensitive to occult fractures and osteonecrosis of bones and soft tissue injury and ligament injury

15. SOME SPECIFIC RADIOLOGICAL VIEWS WRIST INJURY Scaphoid view: It is anteroposterior x-ray with wrist supinated 30 degree and ulnar deviation Pronated oblique view: To look for schaphoid fracture Clenched fist AP view: To look for widening of scapholunate interval Maximal ulnar & radial deviation : To look for carpal instability

16. APPLIED ANATOMY Ossification of carpal bones

17. ANATOMICAL SNUFF BOX

18. BLOOD SUPPLY OF SCAPHOID The scaphoid is at particular risk of avascular necrosis after fracture because of its retrograde blood supply

19. CLINICAL CONDITION AFFECTING WRIST JOINT Fracture of distal radius Fracture of carpel bone Adults: Colles fracture Smith fracture Barton’fracture Radial styloid fracture Children Fracture of distal radial epiphysis Fracture of distal radial metaphysis scaphoid fracture Lunate fracture Perilunate dislocation Dorsal chip fracture

20. SUMMARY Wrist joint is also known as radio carpal joint which is a synovial joint of ellipsoid type Colles fracture is the fracture of distal end of radius in a skeletally mature person produced by a fall on outstreched hand The most common mechanism of carpal bones injury in hand is fall onto outstretched, due to axial compressive force with the wrist in hyperextension Scaphoid fracture is the commonest injury of carpus Carpal tunnel syndrome is due to compression of median nerve causing numbness and tingling or weakness in hand

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