wrist/hand


WRIST AND HAND – BONES AND JOINTS




Intended Learning Outcomes



  • Identify bony landmarks of the wrist and hand

  • Describe bones and joints of the wrist and hand






BONY LANDMARKS




Distal Forearm



  • Distal radius

  • Distal ulna






CARPAL BONES (8 BONES)




Proximal Row (lateral → medial, thumb to little finger)



  • Scaphoid

  • Lunate

  • Triquetral

  • Pisiform




Distal Row (lateral → medial)



  • Trapezium

  • Trapezoid

  • Capitate

  • Hamate






INDIVIDUAL CARPAL BONES




Scaphoid



  • Has a palpable tubercle

  • Important for blood supply

  • High risk of avascular necrosis after fracture




Lunate



  • Articulates with:

    • Scaphoid

    • Triquetral





Triquetrum and Pisiform



  • Pisiform:

    • Sesamoid bone

    • Located in tendon of flexor carpi ulnaris

    • Lies on palmar surface of triquetral

    • Palpable on medial side of wrist





Trapezium



  • Has a palpable tubercle

  • Forms 1st carpometacarpal (CMC) joint with thumb

  • Important for thumb mobility




Capitate



  • Largest carpal bone

  • Articulates with base of 3rd metacarpal




Hamate



  • Has hook of hamate (palpable)

  • Located in hypothenar region

  • Articulates with 4th and 5th metacarpals






BONES OF THE HAND




Metacarpals



  • 5 bones (MC1–MC5)




Phalanges (14 total)



  • 5 digits:

    • Thumb = 2 phalanges (proximal, distal)

    • Fingers = 3 phalanges (proximal, middle, distal)





Articulations



  • Proximal phalanx → metacarpal + middle phalanx

  • Middle phalanx → proximal + distal

  • Distal phalanx → middle phalanx






JOINTS OF THE WRIST AND HAND



  • Radiocarpal joint

  • Midcarpal joint

  • Intercarpal joints

  • Carpometacarpal (CMC) joints

  • Metacarpophalangeal (MCP) joints

  • Interphalangeal (IP) joints






RADIOCARPAL JOINT (WRIST JOINT)




Type



  • Synovial ellipsoid




Articular Surfaces



  • Distal radius

  • Triangular fibrocartilage disc

  • Scaphoid, lunate, triquetral




Ligaments



  • Palmar radiocarpal

  • Dorsal radiocarpal

  • Radial collateral

  • Ulnar collateral




Movements



  • Flexion

  • Extension

  • Radial deviation

  • Ulnar deviation






MIDCARPAL JOINT




Type



  • Synovial complex saddle




Location



  • Between proximal and distal carpal rows




Ligaments



  • Intercarpal (palmar and dorsal)

  • Collateral ligaments




Movements



  • Flexion

  • Extension

  • Abduction

  • Adduction






FIRST CARPOMETACARPAL (CMC) JOINT (THUMB)




Articular Surfaces



  • Trapezium

  • Base of 1st metacarpal




Ligaments



  • Radial CMC

  • Anterior and posterior oblique




Movements



  • Flexion

  • Extension

  • Abduction

  • Adduction

  • Opposition






INTERCARPAL JOINTS




Type



  • Synovial plane joints




Location



  • Between individual carpal bones




Ligaments



  • Dorsal intercarpal

  • Palmar intercarpal

  • Interosseous




Movements



  • Small gliding movements

  • Most significant at capitate






METACARPOPHALANGEAL (MCP) JOINTS




Type



  • Synovial ellipsoid




Articular Surfaces



  • Metacarpal head + base of proximal phalanx




Ligaments



  • Palmar ligaments

  • Collateral ligaments

  • Deep transverse metacarpal ligament




Movements



  • Flexion

  • Extension

  • Abduction

  • Adduction






INTERPHALANGEAL (IP) JOINTS




Type



  • Synovial hinge




Types



  • Proximal IP (PIP)

  • Distal IP (DIP)




Ligaments



  • Collateral

  • Palmar




Movements



  • Flexion

  • Extension






WRIST AND HAND – MOVEMENTS AND MUSCLES




Intended Learning Outcomes



  • Describe movements at wrist and hand

  • Name muscles acting on wrist and hand






WRIST MOVEMENTS (RADIOCARPAL + MIDCARPAL)




Normal Range of Motion



  • Flexion: ~85°

  • Extension: ~85°

  • Radial deviation: ~15°

  • Ulnar deviation: ~45°




Contribution of Joints



  • Flexion:

    • Midcarpal = 60%

    • Radiocarpal = 40%


  • Extension:

    • Radiocarpal = 60%

    • Midcarpal = 40%


  • Radial/Ulnar deviation:

    • Mainly radiocarpal







THUMB MOVEMENTS (CMC JOINT)




Flexion / Extension



  • Range: 40–50°

  • Flexion muscles:

    • Flexor pollicis brevis (FPB)

    • Flexor pollicis longus (FPL)

    • Opponens pollicis


  • Extension muscles:

    • Extensor pollicis longus (EPL)

    • Extensor pollicis brevis (EPB)

    • Abductor pollicis longus (APL)







Abduction / Adduction



  • Range: ~80°

  • Abduction:

    • Abductor pollicis longus (APL)

    • Abductor pollicis brevis (APB)


  • Adduction:

    • Adductor pollicis

    • 1st palmar interosseous







Opposition



  • Combination of:

    • Flexion

    • Abduction

    • Medial rotation

    • Adduction


  • Muscles:

    • Flexor pollicis longus

    • Flexor pollicis brevis

    • Abductor pollicis longus

    • Opponens pollicis

    • Adductor pollicis







MUSCLES OF THE WRIST




Wrist Flexors



  • Flexor carpi ulnaris

  • Flexor carpi radialis

  • Palmaris longus

  • Flexor digitorum superficialis

  • Flexor digitorum profundus

  • Flexor pollicis longus






Wrist Extensors



  • Extensor carpi radialis longus

  • Extensor carpi radialis brevis

  • Extensor carpi ulnaris

  • Extensor digitorum

  • Extensor digiti minimi

  • Extensor indicis

  • Extensor pollicis longus

  • Extensor pollicis brevis






Radial Deviation



  • Flexor carpi radialis

  • Extensor carpi radialis longus

  • Extensor carpi radialis brevis

  • Abductor pollicis longus

  • Extensor pollicis brevis






Ulnar Deviation



  • Flexor carpi ulnaris

  • Extensor carpi ulnaris






MUSCLES OF THE THUMB



  • Flexion: Flexor pollicis longus and brevis

  • Extension: Extensor pollicis longus and brevis

  • Abduction: Abductor pollicis

  • Adduction: Adductor pollicis

  • Opposition: Opponens pollicis






MUSCLES OF THE FINGERS




Flexion



  • Flexor digitorum superficialis

  • Flexor digitorum profundus




Extension



  • Extensor digitorum

  • Extensor digiti minimi

  • Extensor indicis




Abduction



  • Dorsal interossei




Adduction



  • Palmar interossei






Little Finger Specific Muscles



  • Flexion: Flexor digiti minimi

  • Abduction: Abductor digiti minimi

  • Opposition: Opponens digiti minimi






EXAM-IMPORTANT POINTS




Carpal Bones (memorise order)



  • Scaphoid, Lunate, Triquetral, Pisiform

  • Trapezium, Trapezoid, Capitate, Hamate






Midcarpal Joint Movements



  • Flexion

  • Extension

  • Abduction

  • Adduction






Wrist Flexion Muscles (examples)



  • Flexor carpi radialis

  • Flexor carpi ulnaris

  • Palmaris longus



1. Radiocarpal Joint (Wrist Joint)

Type

  • Synovial ellipsoid

Articular Surfaces

  • Distal radius

  • Triangular fibrocartilage disc

  • Scaphoid

  • Lunate

  • Triquetral

Ligaments

  • Palmar radiocarpal

  • Dorsal radiocarpal

  • Radial collateral

  • Ulnar collateral

Movements

  • Flexion

  • Extension

  • Radial deviation

  • Ulnar deviation


2. Midcarpal Joint

Type

  • Synovial complex saddle

Location

  • Between proximal and distal carpal rows

Ligaments

  • Intercarpal (palmar and dorsal)

  • Collateral ligaments

Movements

  • Flexion

  • Extension

  • Abduction

  • Adduction


3. First Carpometacarpal (CMC) Joint (Thumb)

Articular Surfaces

  • Trapezium

  • Base of 1st metacarpal

Ligaments

  • Radial CMC

  • Anterior oblique

  • Posterior oblique

Movements

  • Flexion

  • Extension

  • Abduction

  • Adduction

  • Opposition


4. Intercarpal Joints

Type

  • Synovial plane joints

Location

  • Between individual carpal bones

Ligaments

  • Dorsal intercarpal

  • Palmar intercarpal

  • Interosseous

Movements

  • Small gliding movements

  • Most significant at capitate


5. Metacarpophalangeal (MCP) Joints

Type

  • Synovial ellipsoid

Articular Surfaces

  • Metacarpal head + base of proximal phalanx

Ligaments

  • Palmar ligaments

  • Collateral ligaments

  • Deep transverse metacarpal ligament

Movements

  • Flexion

  • Extension

  • Abduction

  • Adduction


6. Interphalangeal (IP) Joints

Type

  • Synovial hinge

Types

  • Proximal interphalangeal (PIP)

  • Distal interphalangeal (DIP)

Ligaments

  • Collateral

  • Palmar

Movements

  • Flexion

  • Extension