Lec#9-B.WRIST JOINT & HAND.presentation.

the presentation is about anatomy of hand and wrist and its abnormalities

1. Wrist and Hand 1

2. Contents Wrist joint Hand Bones Joints Ligaments Muscles Retinaculum Palmer aponeurois Dorsal digital expansion 2

3. Terminology Wrist: as a joint, it is the articulation between the forearm and hand. Hand: the bones distal to the wrist joint. As a region, the wrist is part of the hand. 3

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5. Bones 29 bones including: (2 from the forearm, 27 from the hand) distal aspect of the radius and ulna 8 carpal (bulk of the hand) 14 phalanges (the fingers) 5 metacarpals total: 2+8+14+5=29 5

6. Bones Radius and Ulna the radius is more massive distally than the ulna the ulna is more massive proximally than the radius Remember, forearm pronation and supination are the result of the radius rotating about the ulna 6

7. Bones Carpal Bones 8 total 2 rows of 4 Proximal row: pisiform, triquetrum, lunate, scaphoid Distal row: hamate, capitate, trapezoid, trapezium 7

8. Bones Metacarpals 5 Phalanges 3 per finger 2 per thumb 8

9. Joints of the Wrist and Hand Carpus/Wrist complex Distal Radioulnar Joint Radiocarpal joints Metacarpal joints Intercarpal Joint Carpometacarpal jts Intermetacarpal jts. Fingers & thumb Metacarpophalangeal Interphalangeal 9

10. Joints Wrist Joint Classified as a Condyloid Joint allows for flexion, extension, radial and ulnar deviation Remember, radius=thumb side The motion of the wrist is due to the articulation of the radius and proximal carpal bones ( or Radiocarpal joint ). There is an articular disk between the distal aspect of the ulna and triquetrum 10

11. Joints Proximal and distal interphalangeal joints Fingers: classified as hinge ( ginglymus ) joints allows for flexion and extension Thumb: consists of three joints, the first two are classified as hinge ( ginglymus ) joints metacarpophalangeal : g.j . interphalangeal: g.j . carpometacarpal: trapezium and metacarpal; saddle jt. 11

12. Movements of the wrist and hand Wrist (remember start from anatomical position) Flexion (or palmer flexion): anterior deviation from anatomical position. Extension: dorsal flexion Abduction (or radial deviation or radial flexion) Adduction (or ulnar deviation or ulnar flexion) 12

13. Movements Fingers Flexion: anteriorly directed movement Extension Abduction: movement of the fingers away from the midline of the hand. Adduction Thumb opposition: movement of the thumb to oppose any of the phalanges 13

14. Muscles of the Wrist and Fingers There are 15 critical muscles 6 muscles are group as primary movers for wrist flexion and extension actions 9 muscles are group as primary movers for hand (finger) of the 15 muscles 6 are primary movers for wrist ulnar deviation 2 are primary movers for wrist radial deviation 14

15. Muscles causing wrist actions Wrist flexors flexor carpi radialis flexor carpi ulnaris palmaris longus Wrist extensors extensor carpi radialis longus extensor carpi radialis brevis extensor carpi ulnaris 15 These muscles do not cause finger movements

16. Muscles Finger flexors flexor digitorum superficialis flexor digitorum profundus Thumb flexor flexor pollicis longus Finger extensors extensor digitorum extensor indicis extensor digiti minimi Thumb extensor extensor pollicis longus extensor pollicis brevis 16 These muscles assist in wrist actions

17. Muscles Wrist radial flexors flexor carpi radialis extensor carpi radialis longus extensor carpi radialis brevis abductor pollicis longus extensor pollicis longus extensor pollicis brevis 17

18. Muscles Wrist ulnar flexors flexor carpi ulnaris extensor carpi ulnaris 18

19. Wrist flexors Origins generally on the anteromedial aspect of the proximal aspect of the forearm and medial epicondyle Insertions: anterior aspect of the wrist and hand Wrist extensors origins: posterolateral aspect of the proximal forearm & lateral humeral epicondyle insertions: posterior aspect of wrist and hand 19

20. Wrist abductors Origin: anterior or posterior aspect of forearm Insertion: radial side of hand Wrist adductors Origin: ant or post aspect of forearm Insertion: ulnar side of hand 20

21. Muscles of the Wrist and Hand Wrist extensors Brachioradialis ECRL ECRB Extensor digitorum Extensor carpi ulnaris Wrist flexors Palmaris longus Flexor carpi radialis Flexor carpi ulnaris Flexor digitorum superficialis 21

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31. Ulnar abductors Extensor carpi ulnaris Flexor carpi ulnaris Radial abductors ECRL Flexor carpi radialis Abductor pollicis longus Extensor pollicis brevis 31

32. Extrinsic hand muscles Extensor digitorum Extensor indicis proprius Extensor digiti minimi Extensor pollicis longus Extensor pollicis brevis Abductor pollicis longus Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus 32

33. JOINT CAPSULE (Capsular Ligament) Like any synovial joint, the capsule is double layered. The fibrous outer layer attaches to the distal ends of radius, ulna and the proximal row of the carpal bones. The internal layer, synovial membrane extends up to the margins of the articular surfaces. 33

34. LIGAMENTS The ligaments of the wrist complex are designated either – extrinsic or intrinsic. Extrinsic ligaments are those that connect the carpals to the radius or ulna proximally or to the metacarpals distally . Intrinsic ligaments are those that interconnect the carpals themselves & also known as intercarpal / interosseous ligaments. There are four ligaments in the wrist joint, one for each side of the joint. Palmar radiocarpal (on anterior side of the hand). It passes from the radius to both rows of carpal bones. 34

35. Dorsal radiocarpal (the dorsum (posterior) side of the hand). It passes from the radius to both rows of carpal bones. Ulnar collateral Runs from the ulnar styloid process to the triquetrum and pisiform. Radial collateral Runs from the radial styloid process to the scaphoid and trapezium. Works in union with the other collateral ligament to prevent excessive lateral joint displacement. 35

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37. Retinaculum 37 A  retinaculum  (plural  retinacula ) is a band of thickened deep fascia around tendons that holds them in place. It is not part of any muscle. Its function is mostly to stabilize a tendon. The term  retinaculum  is New Latin, derived from the Latin verb retinae (to retain). In the wrist: Flexor retinaculum of the hand Extensor retinaculum of the hand

38. Flexor retinaculum of the hand The  flexor retinaculum  ( transverse carpal ligament , or  anterior annular ligament ) is a fibrous band on the palmar side of the hand near the wrist. It arches over the  carpal bones  of the hands, covering them and forming the  carpal tunnel . 38

39. Function: The flexor retinaculum is the roof of the  carpal tunnel , through which the  median nerve  and tendons of muscles which flex the hand pass. Protection and maintaining the tendons in position 39

40. Extensor retinaculum of the hand The  extensor retinaculum  ( dorsal carpal ligament , or  posterior annular ligament ) is an anatomical term for the thickened part of the  antebrachial fascia  that holds the tendons of the extensor muscles in place. It is located on the back of the  forearm , just  proximal  to the hand. It is continuous with the  palmar carpal ligament , which is located on the anterior side of the forearm. 40

41. Anatomical snuff box It is a triangular hollow situated on lat. Side of back of thumb near wrist joint. Boundaries: Laterally: radial side tendons of APL & EPB Medially: ulnar side tendon of EPL Floor: back of scaphoid and trapezium 41

42. PALMAR APONEUROSIS   42

43. PALMAR APONEUROSIS   Also called palmar fascia invests the muscles of the palm consists of central, lateral, and medial portions. 43

44. Functions of palmar aponeurosis Provides firm attachment to overlying skin Helps to form the ridges in the palm which in turn help to increase friction so that we can grasp objects firmly. Protects underlying structures Provides attachment to muscles 44

45. Flexor Tendon Dorsal Digital Expansion 45 dorsal digital expansion . a triangular aponeurotic extension of the  digital  extensor tendon  on the dorsum of the proximal phalanx of each digit, to which the  tendons of the lumbrical and interosseous muscles are also attached. It forms a movable hood around the metacarpophalangeal joint.

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47. Thenar muscles: Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis Adductor pollicis (Deep muscle) 47

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49. Hypothenar muscles Flexor digiti minimi Opponens digiti minimi Abductor digiti minimi *Palmaris brevis (superficial muscle) 4 Palmar interosseous 4 Dorsal interosseous 49

50. Dorsal digital expansion Each extensor tendon covers the dorsal surface of head of metacarpal and proximal phalanx and forms triangular shaped dorsal digital expansion Base: expansions forms a hood over metacarpal head Apex: expansion at the distal end of proximal phalanx trifurcates into a median and two lateral bands. 50

51. Summary The  wrist  is a complex joint that bridges the  hand  to the forearm. It is actually a collection of multiple bones and joints. The bones comprising the  wrist  include the distal ends of the radius and ulna, 8 carpal bones, and the proximal portions of the 5 metacarpal bones. 51