Interosseous metacarpal ligaments

At a glance

English

Interosseous metacarpal ligaments

Latin (TA2)

Ligamenta metacarpea interossea

System

Ligament

Region

Hand

Side

Paired, left and right

About the interosseous metacarpal ligaments

The bases of the second to fifth metacarpals touch one another at small articular facets and form the intermetacarpal joints. Three sets of ligaments hold them: dorsal, palmar and interosseous. The interosseous metacarpal ligaments are the deep set. They join the rough facing sides of adjacent bases a little distal to the facets, so they lie at the front edge of each joint and seal off its distal end.

The intermetacarpal joints are plane synovial joints, and their cavities open proximally into the common carpometacarpal joint that serves the medial four metacarpals. The base of the thumb metacarpal is not joined to the index metacarpal by any of these ligaments; it has its own saddle-shaped joint with the trapezium, which gives the thumb its wide range of motion.

In the hand these ligaments help create a fixed central unit. The second and third metacarpals are held almost immovably against the trapezoid and capitate and against each other, giving a stable post against which the fingers and thumb work. The fourth and fifth metacarpals move a little more, letting the ulnar side of the palm cup during a strong grip, and the interosseous ligaments allow this slight motion while preventing the bases from separating. Further out, the metacarpal heads are linked by the deep transverse metacarpal ligament.

These bands are injured in fractures and dislocations at the carpometacarpal joints, most often at the bases of the fourth and fifth metacarpals after a punch. Stable fixation of a base fracture depends partly on whether the neighbouring interosseous ligament is still intact, which tends to hold the fragments in line.

Attachments and function

Attaches from

Non-articular side of the base of each of the second to fourth metacarpals, just distal to the contact facets.

Attaches to

Facing side of the base of the neighbouring metacarpal, from the third to the fifth.

Function

Bind the metacarpal bases, close the intermetacarpal joint spaces distally and allow only slight gliding, most at the fourth and fifth.

Nerve supply

Articular twigs of the deep branch of the ulnar nerve and of the anterior and posterior interosseous nerves.

Blood supply

Branches of the deep palmar arch and the dorsal carpal arch through the metacarpal arteries.