Anatomy of Wrist and Hand Explained

Oct 17, 2024

Anatomy of the Wrist and Hand

Overview

  • The wrist and hand are complex structures with numerous bones and ligaments, allowing for complex movements aided by various muscles.
  • Key components include bones, joints, ligaments, and muscles.

Bones of the Wrist and Hand

Forearm Bones

  • Radius: Located on the thumb side.
  • Ulna: Located on the pinky side, medial in anatomical position.

Carpal Bones

  • Mnemonic: "So long to pinky, here comes the thumb"
  • Proximal Row:
    • Scaphoid: Associated with scabs.
    • Lunate: Named for a moon-like shape.
    • Triquetrum: Third bone, articulates with the radiocarpal joint.
    • Pisiform: Anterior bone, prominent on the pinky side.
  • Distal Row:
    • Hamate: Has a hook.
    • Capitate: Central and head-like.
    • Trapezoid: Named after a geometric shape.
    • Trapezium: Rhymes with thumb.

Metacarpals

  • Bones of the hand, numbered 1-5 starting with the thumb.
  • Thumb: Referred to as "pollux."

Phalanges

  • Thumb: Proximal and distal phalanges.
  • Fingers: Proximal, middle, and distal phalanges.

Joints of the Wrist and Hand

Major Joints

  • Radiocarpal Joint: Condyloid joint allowing flexion, extension, abduction, and adduction.
  • Carpometacarpal Joints:
    • Saddle joint in the thumb (trapeziometacarpal joint).
    • Condyloid joints for digits 2-5.
  • Metacarpophalangeal Joints: Condyloid joints allowing flexion/extension and abduction/adduction.
  • Interphalangeal Joints: Hinge joints with proximal and distal varieties.

Ligaments

  • Radial Collateral Ligament: Prevents over-adduction.
  • Ulnar Collateral Ligament: Prevents over-abduction.
  • Palmar Radiocarpal Ligament: Prevents overextension.
  • Dorsal Radiocarpal Ligament: Prevents overflexion.

Muscles of the Radiocarpal Joint

Movements and Major Muscles

  • Flexion:
    • Flexor Carpi Ulnaris: Causes flexion and adduction.
    • Flexor Carpi Radialis: Causes flexion and abduction.
  • Extension:
    • Extensor Carpi Ulnaris: Causes extension and adduction.
    • Extensor Carpi Radialis: Includes longus and brevis, causing extension and abduction.
    • Abductor Pollicis Longus: Assists in extension and abduction of the thumb.

Additional Resources

  • Blank diagrams and note sheets available for practice.
  • Further study recommended on ligaments and muscle details.

Conclusion

  • Comprehensive review of the anatomy of the wrist and hand, covering bones, joints, ligaments, and muscles.