Can be subdivided into two separate entities:  Retrocalcaneal and Retroachilles<unk> 
Retrocalcaneal<unk>  - Inflammation of the bursa located posterior to the calacaneal bone, anterior to the achilles tendon
Retroachilles<unk>  - Inflammation of the bursa located between the achilles tendon and posterior skin, adjacent to the insertion of the achilles tendon on the calcaneous
Calcaneal bursitis
Retrocalcaneal bursitis
Olecranon bursitis 
Retroachilles bursitis
Hip bursitis
Septic bursitis
Prepatellar bursitis 
Septic arthritis