<prompt> Kohlers disease is due to osteonecrosis of:CalcaneumTarsal boneTalusHumerus-Capitulum  <response>: B i.e. Tarsal boneRef: Fundamentals of Orthopedics, 2nd edition, Mohindra and Jain, Jaypee Publishers, page 44Explanation:Kohlers disease is osteochondritis of Navicula a tarsal bone.In osteochondritis there occurs degeneration of osteochondral part of joint possibly due to a vascular etiology. However, exact etiology is unknown and the condition is categorized as under based on possible causative mechanisms.Types of OsteochondritisCrushing typeFreibergs disease: Metatarsal heads.Kohlers disease: Navicula Figure.Kienbocks disease Lunate.Parmers disease. Capitulum.Scheuermanns disease: Ring epiphysis of vertebrae.Calves disease: Central bony nucleus of vertebrae.Thiemanns disease: Phalangeal epiphysis.Tractionpulling typeOsgood-Schlatters disease: Tibial tuberosity.Severes disease: Calcaneal epiphysis.Johansson-Larson syndrome: Patellar ligament at its lower pole patellar attachment.Iselins disease: Base of fifth metatarsal.Adams disease: Medial epicondyle of humerus.Splitting typeOsteochondritis dissecans. 