Ligament · Hand

Cruciate pulleys of the fingers

The thin, crossed bands that sit between the annular pulleys in the flexor tendon sheath, three to a finger and numbered C1 to C3. Where an annular pulley is a solid collar over the middle of a bone, a cruciate pulley is a lattice of fibres crossing each other over a joint — and the shape is the point. A solid ring over a bending joint would either buckle or restrict it; a crossed lattice can concertina as the finger closes and open out again as it straightens, keeping the tendon covered and roughly in place without ever getting in the way. They are the flexible links between the rigid ones, which is why they are found over the joints and the annular pulleys are found over the bones.