Deep transverse metacarpal ligament

At a glance

English

Deep transverse metacarpal ligament

Latin (TA2)

Ligamentum metacarpeum transversum profundum

System

Ligament

Region

Hand

Side

Paired, left and right

About the deep transverse metacarpal ligament

This ligament runs across the palm at the level of the knuckles and is also known as the deep transverse palmar ligament. It is a narrow, tough band that links the heads of the index, middle, ring and little finger metacarpals. Rather than attaching directly to bone along its length, it is made of short segments that join the palmar plates of neighbouring metacarpophalangeal joints, so the four plates and the bands between them form one continuous strap. The thumb metacarpal is not included, which leaves the thumb free to move away from the palm.

Its relations are what make it useful as a landmark. In front of it, on its palmar side, the ligament is slightly hollowed where the long flexor tendons in their fibrous sheaths pass over it towards the fingers. The lumbrical muscles and the digital vessels and nerves also lie on its palmar side. Behind it, on the dorsal side, the interosseous tendons run forwards to their insertions on the phalanges and extensor expansions. The ligament therefore separates the lumbricals in front from the interossei behind.

Mechanically, it keeps the metacarpal heads from spreading apart when the hand grips or takes weight, so the palm keeps its shape and the transverse arch at the knuckles is preserved. At the same time it is flexible enough to let the heads move slightly forwards and backwards on each other, which allows the palm to cup.

Rupture of this ligament is rare and usually follows a forceful injury that drives the fingers apart. It is of more interest to surgeons, who use it as a guide to the plane between the interosseous and lumbrical tendons and must protect it when releasing contracted tissue in Dupuytren disease.

Attachments and function

Attaches from

The palmar plate of the metacarpophalangeal joint of the index finger, at the head of the second metacarpal.

Attaches to

Successively the palmar plates of the third, fourth and fifth metacarpophalangeal joints, ending at the head of the fifth metacarpal.

Function

Ties the metacarpal heads of the fingers together, limits their spread during grip and helps maintain the transverse arch of the hand while allowing the palm to cup.

Nerve supply

Articular branches of the digital nerves from the median and ulnar nerves.

Blood supply

Branches of the common palmar digital and palmar metacarpal arteries.