Palmar metacarpal ligaments

At a glance

English

Palmar metacarpal ligaments

Latin (TA2)

Ligamenta metacarpea palmaria

System

Ligament

Region

Hand

Side

Paired, left and right

About the palmar metacarpal ligaments

The palmar metacarpal ligaments are small fibrous bands lying deep in the palm, near the wrist. Each runs crosswise from the palmar side of one metacarpal base to the next, linking the second and third, third and fourth, and fourth and fifth metacarpals. The bands are slightly concave on their palmar face. They strengthen the front of the intermetacarpal joints, the small plane joints where the sides of the bases meet; these joints usually communicate with the carpometacarpal joints just behind.

Each intermetacarpal joint is held by a trio of ligaments. These palmar bands lie in front, the dorsal metacarpal ligaments run the same way on the back, and the interosseous metacarpal ligaments lie between the facing bone surfaces and provide the strongest bond. The thumb metacarpal has no such link to the index, which leaves it free to move across the palm. In front of the palmar bands lie the deep palmar arch with the deep branch of the ulnar nerve, and in front of those the long flexor tendons as they leave the carpal tunnel. The palmar interosseous muscles take origin from the shafts just beyond.

By tying the bases together, the ligaments help create a firm transverse framework for the palm, the arch at the level of the metacarpal bases, and limit movement at the intermetacarpal joints to slight gliding. That small movement is greatest on the ulnar side, where it lets the ring and little finger metacarpals fold forwards when the hand cups.

The palmar bands are rarely injured on their own. They may be torn in fracture-dislocations of the metacarpal bases and must heal well for the hand to keep a stable base for grip.

Attachments and function

Attaches from

The palmar surface of the bases of the second, third and fourth metacarpals.

Attaches to

The palmar surface of the base of the adjacent metacarpal on the ulnar side, from the third to the fifth.

Function

Bind the bases of the finger metacarpals together on the palmar side, help form the transverse arch of the hand and limit intermetacarpal movement to slight gliding.

Nerve supply

Articular branches of the deep branch of the ulnar nerve.

Blood supply

Branches of the deep palmar arch and palmar metacarpal arteries.