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Metacarpophalangeal joint

The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers.[1] These joints 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 proximal phalanges.[1] Being condyloid, they allow the movements of flexion, extension, abduction, adduction and circumduction at the joint.[1]

Metacarpophalangeal joint
Grant 1962 104 MCP.png
The palmar aspect of the hand showing the epiphyses of the hand exploded. MCP joints in red.
DIP, PIP and MCP joints of hand.jpg
The DIP, PIP and MCP joints of the hand: MetaCarpoPhalangeal joint, and the interphalangeal joints of the hand:
  • Distal InterPhalangeal
  • Proximal InterPhalangeal
Details
System099
Identifiers
Latinarticulationes metacarpophalangeae
MeSHD008662
TAA03.5.11.501
FMA35246
Anatomical terminology

StructureEdit

LigamentsEdit

Metacarpophalangeal articulation and articulations of digit. Palmar aspect.
Metacarpophalangeal articulation and articulations of digit. Ulnar aspect.

Each joint has:

Dorsal surfacesEdit

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.

FunctionEdit

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.[2]

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 significanceEdit

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

Other animalsEdit

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.

ReferencesEdit

This article incorporates text in the public domain from page 332 of the 20th edition of Gray's Anatomy (1918)

  1. ^ a b c Drake, Vogl and Mitchell (2015). Grey's Anatomy for Students, 3rd Edition. Churchill Livingstone, Elsevier. p. 796. ISBN 9780702051319.
  2. ^ Gray's Anatomy (1918), see infobox

External linksEdit