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Metacarpophalangeal Joint

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Introduction

Illustration of the metacarpophalangeal joint[1]
natomy of the metacarpophalangeal joint from the ulnar side. 1: proximal phalanx, 2: first metacarpal, 3: UCL, 4: AUCL, 5: palmar proximal ligament, 6: volar, 7: aponeurosis of the adductor, 8: adductor pollicis muscle, 9: sesamoid ulnar bone, 10: extensor tendon, and 11: abductor tendon of the thumb.[2]
Anatomical drawing of the metacarpophalangeal joint: a) longitudinal aspect; b) transversal aspect at level of the proximal phalanx base. MC -metacarpal bone, PP -proximal phalanx, E -extensor tendon, F -flexor tendons (superficial and profound) in the synovial sheath, L -lumbrical tendon, I -interosseous tendon, S -sagittal band, MCL -main collateral ligament, ACL -accessory collateral ligament, DLT -deep transverse metacarpal ligament, black arrow -dorsal plate, white arrowpalmar (volar) plate.[3]

Alternative Names

  • MCPJ
  • Knuckle Joint
  • Finger Knuckle Joint
  • Metacarpal Phalangeal Joint
  • Metacarpophalangeal Articulation
  • Digital Knuckle Joint
  • Finger MCP Joint

General

Anatomic Description

  • Metacarpal head: asymmetric in coronal, sagittal planes
  • Articular surface forms a condyloid joint with the shallow, concave proximal phalanx

Capsule

  • Extends from the metacarpal neck to the base of the proximal phalanx
  • Reinforced by ligamentous structures on all sides (see below)

Stabilizing Structures and Actions

  • Proper Collateral Ligaments
    • Origination: dorsal aspect of metacarpal head
    • Insertion: volar aspect of base of proximal phalanx
    • Function: Primary stabilizer of MCPJ, most stability provided during flexion[4]
  • Accessory Collateral Ligaments
    • Origination: volar to the proper collateral ligaments
    • Insertion: volar plate
    • Function: Provide stability in flexion
  • Volar Plate
    • Function: stabilizes the volar aspect of MCP joint, allows hyperextension of MCPJ
    • Thick fibrocartilaginous portion distally, loose membranous portion proximally
    • Proximal portion does facilitate some hyperextension of the MCPJ[5]
  • Dorsal Capsule
    • Function: weak stabilizer of the dorsal aspect of MCP joint
    • Capsule is thin and loose here, most vulnerable
    • Extrinsic extensor tendons are supported by the sagittal band of the extensor hood
  • Sagittal Bands
    • Origination: from the extensor hood
    • Insertion: attaches volarly with transverse metacarpal ligament
    • Function: supports the extrinsic tendons

Movement

  • Multiplanar: flexion, extension, abduction, adduction, and circumduction
  • Enabled by complex shape of metacarpal head, articular surface, supporting soft tissue structures
  • Total range of motion of MCPJ is greater than that of the proximal and distal interphalangeal joints

Thumb MCP Joint

  • Similar to the MCP Joint of other ringers with the following exceptions
  • More hinge-like than multi-axial
  • Sesamoid Bones lie anterior to the metacarpal head, articulate with it
  • Stabilized by similar ligament complex
  • Stability is necessary to facility pinch and grasp

Vascular Supply

  • Branches of the interdigital arteries

Nerve

  • Branches of the interdigital nerves

Clinical Significance

See Also

Reference

  1. ↑ Image courtesy of teachmenanatomy.info, "metacarpophalangeal"
  2. ↑ Cagnolati, Amanda Favaro, et al. "Ultrasonographic characterization of the ulnar collateral ligament of normal thumbs in different age groups." Clinics 73 (2018): e162.
  3. ↑ Fodor, Daniela, et al. "Ultrasonography of the metacarpophalangeal joints in healthy subjects using an 18 MHz transducer." Medical Ultrasonography 17.2 (2015): 185-191.
  4. ↑ Minami, Akio, et al. "Ligament stability of the metacarpophalangeal joint: a biomechanical study." The Journal of hand surgery 10.2 (1985): 255-260.
  5. ↑ Zemel, Norman P. "Metacarpophalangeal joint injuries in fingers." Hand clinics 8.4 (1992): 745-754.
Created by:
John Kiel on 16 August 2019 00:42:15
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Last edited:
10 May 2026 22:30:46
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