The metacarpophalangeal joints (MCP) are condyloid type joints, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the first phalanges. The exception is the thumb, which presents more of the characters of a ginglymoid joint. Arthritis of the MCP is a distinguishing feature of rheumatoid arthritis, as opposed to the distal interphalangeal joint in osteoarthritis.


Metacarpophalangeal articulation and articulations of digit; volar aspect left, ulnar aspect right

Ligaments

Each joint has

  • Palmar ligaments of metacarpophalangeal articulations
  • Collateral ligaments of metacarpophalangeal articulations

Dorsal surfaces

The dorsal surfaces of these joints are covered by the expansions of the extensor tendons, together with some loose areolar tissue which connects the deep surfaces of the tendons to the bones.

Movements

The movements that occur in these joints are flexion, extension, adduction, abduction, and circumduction. The movements of abduction and adduction are very limited, and cannot be performed while the fingers form a fist.

The muscles of flexion and extension are as follows:

Location

Flexion

Extension

Fingers

Flexor digitorum superficialis and profundus, lumbricales, and interossei, assisted in the case of the little finger by the flexor digiti minimi brevis

Extensor digitorum communis, extensor indicis proprius, and extensor digiti minimi muscle

Thumb

Flexor pollicis longus and brevis

Extensor pollicis longus and brevis

Attachments:


Metacarp 1.png (image/png)


Metacarp 2.png (image/png)