Kienbock disease is avascular necrosis of:

Ans. (d) LunateRef: Maheshwari 5th ed. / 318* It is breakdown of the lunate bone, a carpal bone in the wrist that articulates with the radius in the forearm.* Specifically, Kienbock's disease is another name for avascular necrosis with fragmentation and collapse of the lunate.* This has classically been attributed to arterial disruption, but may also occur after events that produce venous congestion with elevated inter-osseous pressure.