Metacarpophalangeal joint (finger)

Metacarpophalangeal (MCP) joints are condyloid synovial joints between the metacarpal bones and proximal phalanges of the hands.

This article is focused on the metacarpophalangeal joints of the fingers.

Gross anatomy

Articulation

Each joint occurs between the round head of the metacarpal and the shallow base of the proximal phalanx ^1,2.

Movement

• flexion

• extension

• abduction

• adduction

• circumduction

Joint capsule

Each joint is enclosed by a fibrous capsule which attaches to the margins of the articular surfaces and is lined by a synovial membrane ².

Attachments

Ligamentous

• two proper collateral ligaments

  • paired radial and lateral bands that strengthen the capsule on each side ^1-3

  • pass slightly obliquely from the posterior tubercle of the metacarpal head to insert on the proximal phalanx just distal to the articular surface and dorsal to the volar cortex ^1-4

  • taut in flexion ^3,4

• two accessory collateral ligaments

  • arise volar to the proper collateral ligaments and fan out to insert on the volar plate ³

  • taut in extension ^3,4

• volar plate (palmar ligament)

  • distal thick fibrocartilaginous plate attaching firmly to periosteum at the base of the proximal phalanx and becomes thin and membranous proximally attaching loosely to the metacarpal neck ^1-4

  • limits hyperextension ⁴

• deep transverse metacarpal ligament: attaches volar plates of adjacent fingers together ⁴

Tendinous

• sagittal band: inserts onto volar plate and deep transverse metacarpal ligament ⁴

• A1 flexor pulley inserts onto the volar plate ⁴

Blood supply

• deep digital arteries from the superficial palmar arch ^1,2

Innervation

• digital nerves from the ulnar and median nerves ^1,2

Related pathology

• hitchhiker thumb deformity