The Wrist & Joints of the Hand

collateral ligaments hand midcarpal joint radiocarpal joint skeleton of the hand wrist joint

The Skeleton of the Hand

  • Divided into 3 Anatomical Regions:
    • Carpus - 8 short bones arranged into a proximal row (scaphoid, lunate, triquetral and pisiform) and a distal row (trapezium, trapezoid, capitate and hamate)
    • Metacarpals (5)
    • Phalanges (14 - 2 in the thumb and 3 in the remaining 4 digits)

    The Wrist Joint

    • Functionally the wrist is made up of the radiocarpal, midcarpal and intercarpal joints
    • Anatomically the wrist is made up of the radiocarpal joint
      • the proximal row of carpal bones (scaphoid, lunate and triquetral) 
      • the radius and the fibrocartilagenous disc 

    The Radiocarpal Joint

    • Classified as  synovial ellipsoid joint
    • Articular surfaces
      • Inferior aspect of radius (note triangular and quadrilateral facet) covered in hyaline cartilage and inferior aspect of fibrocartilagenous disc - form biconcave surface
      • Proximal aspect of scaphoid, lunate and triquetral (all covered with hyaline cartilage) - form biconvex surface

    The Radiocarpal Joint - Capsule

    • Series of irregular bands passing from distal end of radius and ulna anteriorly and posteriorly to articular margins of scaphoid, lunate and triquetral
    • Medially and laterally extend from styloid processes of radius and ulna to sides of scaphoid (laterally) and triquetral (medially)
    • Lined with synovial membrane

    Palmar (Volar) Ligaments

    • Series of thickenings across the anterior capsule
    • Anatomically divided into 
      • Palmar radiocarpal ligament passing from anterior radius to proximal row and capitate
      • Palmar ulnocarpal ligament passing from disc and ulnar styloid to proximal row (mostly triquetral and lunate) 

    Dorsal Radiocarpal Ligament

    • From posterior lower radius to proximal row of carpal bones (scaphoid, lunate and triquetral)
    • Weak and more commonly injured
    • Palmar ligaments limit extension while dorsal ligaments limit flexion 

    Collateral Ligaments

    • Limit abduction / adduction of the wrist
    • Radial collateral - flat band from apex of radial styloid to lateral scaphoid
    • Ulnar collateral - cord from apex of ulnar styloid to triquetral and pisiform

    Joints of the Carpal Bones

    • Series of synovial plane joints between adjacent bones forming part of the functional wrist joint
    • Produce a small amount of gliding to allow normal movements at the wrist:
      • Joints of the proximal row - between scaphoid/lunate, lunate/triquetral and triquetral / pisiform
      • Joints of the distal row - between trapezium / trapezoid, trapezoid / capitate and capitate / hamate
      • All reinforced by palmar, dorsal and interosseus ligaments 

    Midcarpal Joint

    • Formed between the proximal row (scaphoid, lunate and triquetral) and the distal row (trapezium, trapezoid, capitate and hamate)
    • Class - synovial compound, biaxial joint
    • Forms an irregular joint line - S shape from medial to lateral
    • All articular surfaces covered with hyaline cartilage
    • Surrounded by a capsule (irregular bands of fibres) which is lined with an irregular synovial membrane

    Ligaments of the Midcarpal Joint

    • Palmar Intercarpal  ligaments - strong bands passing from the capitate to the proximal row of bones
    • 2 main bands (pictured) pass to scaphoid and triquetral
    • A thinner band passes from capitate to lunate - a potentially weak space which may allow lunate or capitate to dislocate anteriorly

    Dorsal Intercarpal Ligaments

    • Short series of fibres uniting adjacent bones
    • Weak and more prone to injury than the anterior ligaments

    Collateral Ligaments

    • Midcarpal joint is further reinforced by collateral fibrous bands limiting abduction / adduction:
      • Radial collateral ligament - continuation of the RC ligament of the radiocarpal joint - strong, flat band passing from scaphoid to trapezium
      • Ulnar collateral ligament - from triquetral to hamate
      • Both often included as part of the palmar intercarpal ligaments

      Movements of the Functional Wrist

      • Movements occur at both the radiocarpal joint and midcarpal but in varying degrees


      Total Range

      Range at RC joint

      Range at MC joint


      85º- Limited by dorsal ligaments and extensors





      85º - Limited by palmar ligaments and flexors




      Radial deviation (abduction)

      15º - Limited by ulnar collateral ligaments and ulnar deviators

      Ulnar deviation (adduction)

      45º - Limited by radial collateral ligaments and ulnar deviators




      Surface Anatomy

      • Wrist - a line, concave distally passing from the apex of the radial styloid to the ulnar styloid
      • Midcarpal - identified by palpating the distal line of scaphoid and proximal capitate/hamate

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