Kienböck's disease a tendency of the implant to smooth the edges of the surrounding bones, thus causing painful pinched nerves when the bones slip out of place. After the lunate is removed, another procedure, "ulnar shortening" can be performed. This relieves pressure on the newly formed wrist joint of the pisiform, hamate and capitate. Depending on the surgeon, the procedure may be performed the same way as the "radial shortening" where a small section is removed, or the entire top of the ulna may be excised. At Stage 4, the lunate has completely disintegrated and the other bones in the wrist have
Carpal tunnel to the pisiform and hook of hamate. The narrowest section of the tunnel is located a centimetre beyond the mid-line of the distal row of carpal bones where the sectional area is limited to 1.6 cm. The tendons of the flexor digitorum superficialis and profundus pass through a common ulnar sheath, while the tendon of the flexor pollicis longus passes through a separate radial sheath. The mesotendon shared by these tendons is attached to the radial and palmar walls of the carpal tunnel. Superficial to the carpal tunnel and the flexor retinaculum, the ulnar artery and ulnar nerve pass through