midcarpal joint

• Joint Classification:

  Complex synovial joint
• Axis of movement:

  Two planes of movement
• Articular Surfaces:

  Articulation between proximal and distal row of carpal bones

  • Lateral part of joint

  • Scaphoid articulates with two ‘T’s (trapezium and trapezoid)

  • Two plane surfaces

  • Slightly convex distally
• Articular surfaces:

  • Medial part of joint

  • Scaphoid, lunate and triquetral articulate with capitate and hamate

  • Concave distally
• Joint Capsule:

  • Fibrous capsule

  • Attached to two rows of carpals

  • Strengthened by palmar and dorsal intercarpal ligaments (anteriorly and posteriorly)

  • Strengthened by collateral ligaments (at sides)
• Ligaments:

  Dorsal intercarpal ligaments

  • Ligaments run between bones of proximal and distal rows of carpals

  • Role: Reinforce capsule and stabilise joint
• Ligaments:

  Palmar intercarpal ligaments

  • Aka “radiate capitate ligament”

  • Ligaments run from bones of proximal row predominately to the capitate

  • Role: Reinforce capsule and stabilise joint
• Radial collateral ligament of midcarpal joint:

  • Strong band passing from scaphoid to trapezium

  • Continuation of radial collateral carpal ligament of RC joint

  • Role: Reinforce capsule and stabilise joint
• Ulnar collateral ligament of midcarpal joint:

  • From triquetral to hamate

  • Continuation of ulnar collateral carpal ligament of RC joint

  • Role: Reinforce capsule and stabilise joint
• Flexion:

  35 degrees

  Limited by:

  • Dorsal radiocarpal ligament

  • Posterior capsule

  • Apposition of proximal carpus against radius

  • Wrist and finger extensors
• Extension:

  50 degrees

  Limited by:

  • Palmar radiocarpal and ulnocarpal ligaments.

  • Anterior capsule

  • Apposition of proximal carpus against radius

  • Wrist and finger flexors
• Radial deviation:

  8 degrees

  Limited by:

  • Ulnar collateral ligament

  • Bony apposition of scaphoid against radial styloid
• Ulnar deviation:

  15 degrees

  Limited by:

  • Radial collateral ligament