Metacarpophalangeal joint

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Metacarpophalangeal joint
Gray337.png
Metacarpophalangeal articulation and articulations of digit. Volar aspect.
Gray338.png
Metacarpophalangeal articulation and articulations of digit. Ulnar aspect.
Latin articulationes metacarpophalangeae
Gray's p.332
MeSH Metacarpophalangeal+Joint
Anatomical terminology

The metacarpophalangeal joints (MCP) refer to the joints between the metacarpal bones and the phalanges of the fingers. These are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the first phalanges, with the exception of that of the thumb, which is a saddle joint.

Structure[edit]

Ligaments[edit]

See also: Palmar plate

Each joint has:

Dorsal surfaces[edit]

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.

In other animals[edit]

In many quadrupeds, particularly horses and other larger animals, the metacarpophalangeal joint is referred to as the "fetlock." This term is translated literally as "foot-lock." In fact, although the term fetlock does not specifically apply to other species' metacarpophalangeal joints (for instance, humans), the "second" or "mid-finger" knuckle of the human hand does anatomically correspond to the fetlock on larger quadrupeds. For lack of a better term, the shortened name may seem more practical.

Function[edit]

The movements which 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.[1]

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

Clinical significance[edit]

Arthritis of the MCP is a distinguishing feature of Rheumatoid Arthritis, as opposed to the distal interphalangeal joint in osteoarthritis.

References[edit]

This article incorporates text from a public domain edition of Gray's Anatomy.

  1. ^ Gray's Anatomy (1918), see infobox

External links[edit]