An eight year old Thoroughbred gelding presented to the Cornell Equine and Farm Animal Hospital for two day duration of acute onset of lameness after the owner found a rusty nail in the stall. He had been treated for a hoof abscess for two days with no improvement. Musculoskeletal examination and lameness evaluation revealed several abnormalities of the right forelimb, including increased digital pulses, mild cellulitis from the coronary band to mid-cannon bone, pain elicited on palpation of the deep digital flexor tendon at the level of the second phalanx, and a grade 4/5 lameness (AAEP Scale). There was increased hoof tester sensitivity over the sulcus of the frog and paring of the lateral sulcus of the frog revealed a small pocket of fluid, Initial diagnostics, including radiographs of the foot and pastern with a probe placed retrograde in the draining tract and coffin joint arthrocentesis, were peiformed and ruled out a fracture and septic coffin joint. Based on the placement of the probe into the penetrating wound, it was believed that the most likely cause of the acute lameness was due to a subsolar/solar abscess. The patient was placed on systemic intravenous antibiotics and phenylbutazone in addition to having regional limb perfusions performed and betadine/sugar poultices applied to the hoof. An ultrasound of the pastern was performed and revealed only cellulitis. A palmar digital nerve block resulted in 90% improvement in the right front. After two weeks in hospital, his lameness had improved to grade 3/5 and he was sent home on oral antibiotics. However, three weeks later he returned due to unresolved lameness. Magnetic Resonance Imaging was pe1formed and revealed a penetrating tract originating at the lateral sulcus, through the palmar digital cushion, and leading to a deep digital flexor tendon tear through the lateral lobe. This case demonstrates that the use of MRI with penetrating wound injuries can aid in diagnosis, dete1mining prognosis and treatment.