Dear Patrick and other Indologists,

The kangling (rkang gling) is a human thigh bone trumpet used most prominently in the Tibetan Buddhist tradition known as Chö (gcod) meaning "Severance." If I remember right, Andrea Loseries wrote a book on bone ritual implements in Tibetan Vajrayana, and Ayesha Fuentes recently wrote an important dissertation on Himalayan Buddhist ritual implements made from human bones. 

Allow me some time to find the exact citations and I'll send them along to you shortly.