Exploring Wrist and Hand Anatomy

Oct 16, 2024

Anatomy of the Wrist and Hand

Overview

  • The wrist and hand are complex, with many bones, ligaments, and muscles.
  • The lecture breaks down the anatomy into bones, joints, ligaments, and muscles.
  • Blank diagrams are provided for practice.

Bones of the Hand and Wrist

Forearm Bones

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

Carpal Bones

  • Mnemonic: "So long to pinky, here comes the thumb."
  • Proximal Row:
    • Scaphoid: Remember by associating with a scab on the wrist.
    • Lunate: Named for its moon-like shape.
    • Triquetrum: Third bone in the proximal row.
    • Pisiform: Anterior and easily palpable on the pinky side.
  • Distal Row:
    • Hamate: Has a hook, remember by "hook of hamate."
    • Capitate: Central, named for its "head" position.
    • Trapezoid and Trapezium: Trapezium rhymes with "thumb."

Metacarpals

  • Numbered 1-5 starting with the thumb.
  • Thumb (Pollux): Metacarpal 1.

Phalanges

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

Joints of the Hand and Wrist

Radiocarpal Joint

  • Between the radius and the scaphoid, lunate, and triquetrum.
  • Condyloid joint allowing flexion, extension, abduction, and adduction.

Carpometacarpal Joints

  • First CMC (Trapeziometacarpal): Saddle joint with extensive movement.
  • Digits 2-5 CMC: Varying movement; 5th allows some flexion/extension.

Metacarpophalangeal Joints

  • Allow flexion, extension, and lateral movement.

Interphalangeal Joints

  • Hinge joints in fingers, allowing flexion and extension.

Ligaments of the Radiocarpal Joint

Collateral Ligaments

  • Radial Collateral Ligament: Prevents over-adduction.
  • Ulnar Collateral Ligament: Prevents over-abduction.

Palmar and Dorsal Radiocarpal Ligaments

  • Palmar Radiocarpal Ligament: Prevents overextension.
  • Dorsal Radiocarpal Ligament: Prevents overflexion.

Muscles of the Radiocarpal Joint

  • Focus on four movements: flexion, extension, abduction, and adduction.

Flexor Muscles

  • Flexor Carpi Ulnaris: Flexion and adduction.
  • Flexor Carpi Radialis: Flexion and abduction.

Extensor Muscles

  • Extensor Carpi Ulnaris: Extension and adduction.
  • Extensor Carpi Radialis (Longus and Brevis): Extension and abduction.

Additional Muscle

  • Abductor Pollicis Longus: Assists in extension of the wrist.

Summary

  • Reviewed the anatomy including bones, joints, ligaments, and muscles.
  • Provided mnemonic devices and diagrams for better retention and practice.
  • Encouraged use of practice diagrams for mastery.