Femoral nerve neuropathy of an endurance horse as a sequela of iliopsoas muscle myopathy diagnosed by transrectal ultrasonography.

Femoral nerve neuropathy causes lameness, a condition clinically characterized by stifle's lack of extension with subsequent diminished lower limb function. This case report describes the ultrasonographic diagnosis of femoral neuropathy secondary to compression caused by myopathy of the iliopsoas muscle of an endurance horse during a competition. Transrectal ultrasonography played a pivotal role in diagnosis of the injury by assessment of the involved structures and monitoring of the healing process throughout the recovery period. The horse achieved complete recovery and successfully returned to competition one year post-injury. Transrectal ultrasonography is recommended to evaluate involvement of the femoral nerve in cases with clinical signs suggesting nerve dysfunction.