Scaphocapitate ligament

At a glance

English

Scaphocapitate ligament

Latin (TA2)

Ligamentum scaphocapitatum

System

Ligament

Region

Hand

Side

Paired, left and right

About the scaphocapitate ligament

The scaphocapitate ligament is an intrinsic ligament of the wrist that crosses the midcarpal joint on its palmar side. It runs from the palmar surface of the distal pole of the scaphoid to the palmar surface of the capitate, on the radial side of that bone. It is short and stout and lies close to the joint between the scaphoid and the trapezium and trapezoid.

The distal pole of the scaphoid is held by two groups of short ligaments: this one on its ulnar side, joining it to the capitate, and the scaphotrapeziotrapezoidal ligament on its radial side, joining it to the trapezium and trapezoid. Together they tie the distal scaphoid to the distal carpal row. The proximal pole of the scaphoid, in contrast, is bound mainly to the lunate by the scapholunate interosseous ligament.

The scaphoid is the only bone that spans both carpal rows, and under load it tends to flex. That tendency has to be checked if the proximal row is to stay balanced. The scaphocapitate ligament is one of the restraints that hold the distal scaphoid against the capitate and resist this flexion. When the scapholunate ligament fails, the distal restraints slow the rotary subluxation of the scaphoid, and once they also stretch the scaphoid falls into fixed flexion.

Attachments and function

Attaches from

Palmar surface of the distal pole of the scaphoid.

Attaches to

Palmar surface of the capitate, on its radial side.

Function

Ties the distal scaphoid to the capitate across the midcarpal joint and helps resist flexion of the scaphoid.

Nerve supply

Articular twigs from the anterior interosseous nerve and the deep branch of the ulnar nerve, which supply the palmar side of the carpus.

Blood supply

Small branches of the palmar carpal arch, reinforced by recurrent branches from the deep palmar arch.