Injury of the origin of the gastrocnemius and superficial digital flexor muscles in a Thoroughbred racehorse: An atypical presentation of reciprocal apparatus failure

Damage to the origin of the gastrocnemius and superficial digital flexor muscles has been previously reported as an acute injury in both foals and adult horses. This case report describes, for the first time, the clinical onset of caudal reciprocal apparatus failure in a 2-year-old Thoroughbred. These signs were due to injury of the gastrocnemius and superficial digital flexor muscle origins sustained prior to the onset of lameness. This condition should be considered in cases demonstrating similar clinical signs, even in the absence of known trauma or acute injury to the region.