The calcaneal (intertendinous bursa) lies between the tendons of the gastrocnemius and superficial digital flexor muscles proximal to the hock and extends on the plantar aspect of the calcaneus to the level of the distal tarsus. In most horses, there is a communication between the calcaneal and gastrocnemius bursa and, in approximately a third of horses, with the subcutaneous bursa.
Inflammation and distention of the bursa may or may not be associated with lameness. It may be idiopathic, secondary to trauma or intrathecal hemorrhage, or occur in association with gastrocnemius tendinitis. Septic bursitis may occur secondary to infectious osteitis of the calcaneus or after a penetrating injury.
Horses with septic bursitis need to be treated aggressively with surgical debridement and lavage and appropriate antimicrobial therapy. Horses with aseptic bursitis may be treated with rest, drainage, and intrathecal medication with corticosteroids; results are variable.