Intercarpal Joints

Description

Normal anatomy of the carpal bones. Diagram of the wrist (frontal view) shows the eight carpal bones and the three carpal arcs (Gilula arcs), which are shown as pink (arc I), blue (arc II), and red (arc III) lines. C (capitate), H (hamate), L (lunate), P (pisiform), S (scaphoid), Tm (trapezium), Td (trapezoid), Tr (triquetrum)

Wrist radiograph with carpal bones labeled

Illustration of some of the intercarpal joints

Name

• Intercarpal Joints
• Intercarpal Articulations

General

• Synovial plane joints that connect the the carpal points
• Gathers 3 sets of joints
• Joints of the proximal carpal row, joints of the distal carpal row, Midcarpal joint
• Supported/ fixed by many ligaments, minimal movement
• Help to coordinate movement at the wrist joint and midcarpal joints

Joints of the Proximal Carpal Row

• Connect the relatively flat/ planar surfaces of the scaphoid, lunate, triquetrum
• Forms the scapholunate Joint, lunotriquetral joint
• Pisiform articulates with the palmar of the triquetrum, forming the pisiform joint

Joints of the Distal Carpal Row

• Connects the adjacent trapezium, trapezoid, capitate, hamate
• Forms the trapeziotrapezoid Joint, trapezoideocapitate Joint and capitohamate Joint
• Substantially less mobility than the proximal carpal row

Midcarpal Joint

• Compound articulation between the distal surface of the proximal carpal bones and the proximal surface of the distal carpal bones
• Proximal: Scaphoid, lunate and triquetral bones
• Distal: Trapezium, trapezoid, capitate and hamate bones
• Medial compartment
  • Capitate articulates with concave surface of scaphoid, lunate
  • Triquetrohamate component involves articulation of triquetrum and hamate
• Lateral compartment
  • Trapezium, trapezoid articulate with the scaphoid

Joint Capsule

• Enclosed by an irregular, two layered joint capsule
• Outer layer: fibrous connective tissue provides structural support
• Inner layer: composed of synovial membrane
• Spans the distal surfaces of the proximal carpus to the proximal surfaces of the distal carpus

Ligaments

• Interosseous Intercarpal Ligaments
  • Scapholunate Ligament
  • Lunotriquetral Ligament
• Dorsal Intercarpal Ligaments
• Palmar Intercarpal Ligaments
  • Scaphotrapeziotrapezoid (STT) Ligament
  • Scaphocapitate Ligament
  • Triquetrocapitate Ligament
  • Triquetrohamate Ligament
• Flexor Retinaculum

Innervation

• Anterior Interosseous Nerve
• Posterior Interosseous Nerve

Vascular Supply

• Anastomoses of ulnar artery, radial artery forming:
  • Palmar Carpal Arch
  • Dorsal Carpal Arch

Movement

• Typically follows movement of the radiocarpal joints, often described together
• Slight movement of the midcarpal joint follows the movement of the radiocarpal joint
• Flexion/extension
• Adduction/abduction

Muscles Acting on the Intercarpal Joints

• Flexion: flexor carpi radialis, flexor carpi ulnaris,palmaris longus
  • Assisted by flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus
• Extension: extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris
  • Assisted by extensor digitorum, extensor digiti minimi, extensor indicis, extensor pollicis longus
• Adduction: flexor carpi ulnaris, extensor carpi ulnaris
• Abduction: flexor carpi radialis, extensor carpi radialis longus, extensor carpi radialis brevis
  • Assisted by abductor pollicis longus, extensor pollicis brevis

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Clinical Significance

• Needs to be updated

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See Also

• Wrist Anatomy Main
• Physical Exam Wrist
• Hand Pain Main

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