radiocarpal joint

• Joint Classification:

  Synovial ellipsoidal joint
• Axis of movement:

  Two degrees of freedom
• Articular Surfaces:

  • Scaphoid and lunate with distal radius laterally

  Articular cartilage on lower end radius divided by low ridge into:

  • Lateral triangular area for articulation with scaphoid

  • Medial quadrangular area for articulation with lunate

  Radius and ulnar disc articulating surface is bi-concave
• Articular Surfaces:

  • Triquetral articulates with medial joint capsule

  • Lunate also articulates with articular disc

  • Triangular fibrocartilaginous disc
  • Thicker on its peripherally
  • Articulates proximally with head of ulna and distally with lunate
  • From: (apex) lateral side of the base of the styloid process of the ulna
  • To: (Base) sharp inferior edge of ulna notch on the radius
  • Principle structure uniting the radius and ulna
  • Increases stability at joint
• Joint Capsule:

  • Attaches around articular margins of joint

  • Reinforced anteriorly and posteriorly by capsular thickenings

  • Reinforced medially and laterally by collateral ligaments
• Ligaments:

  Palmar radiocarpal

  • Broad band of fibres

  • From: anterior edge radius

  • To: anterior surface proximal row of carpals, and capitate in distal row

  • Limits: Extension at RC joint
• Ligaments:

  Palmar ulnocarpal

  • From: anterior edge articular disc & base of ulnar styloid

  • To: anterior surface of proximal carpal bones

  • Limits: Extension at RC joint
• Ligaments:

  Dorsal radiocarpal

  • From: posterior edge radius

  • To: posterior surface of scaphoid, lunate and triquetral

  • Limits: Flexion at RC joint
• Ligaments:

  Ulnar (medial) collateral carpal ligament

  • Rounded cord

  • From: ulnar styloid process

  • To: base of pisiform and triquetral

  • Limits: Radial deviation (abduction) at RC joint
• Ligaments:

  Radial (lateral) collateral carpal ligament

  • From: tip of radial styloid

  • To: lateral side scaphoid and trapezium

  • Limits: Ulnar deviation (adduction) at RC joint
• flexion:

  50 degrees

  Limited by:

  • Dorsal radiocarpal ligament

  • Posterior capsule

  • Apposition of proximal carpus against radius

  • Wrist and finger extensors
• extension:

  35 degrees

  Limited by:

  • Palmar radiocarpal and ulnocarpal ligaments.

  • Anterior capsule

  • Apposition of proximal carpus against radius

  • Wrist and finger flexors
• radial deviation:

  7 degrees

  Limited by:

  • Ulnar collateral ligament

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

  30 degrees

  Limited by:

  • Radial collateral ligament