Acute lameness in an adult horseThe degree of lameness was severe. Coffin joint effusion was noted. Hoof tester examination revealed pain over the sole region. The differential diagnosis included pedal osteitis, foot abscess, laminitis, navicular syndrome, puncture wound, and fracture of the third phalanx.A radiographic study of the distal phalanx was performed. A portion of that study is shown. Radiographic diagnosisTwo dorsopalmar views of the distal phalanx are shown. They are made with the horse standing on the protected cassette. Two different radiographic exposures are used. The type 3 sagittal articular fracture line is identified easily. The less dense exposure shows the line through the body of the phalanx while the greater exposure shows the line to enter the coffin joint. The fracture is assumed to be acute because of the clinical history. Because of the minimal amount of callus identified with fractures in this bone, it is perhaps impossible to age the fracture radiographically since the callus is usually not mineralized and thus not identified on the radiograph. Some fractures of the distal phalanx are articular, as in this patient, making this an important feature in treatment and prognosis. Thus, it is important to use a radiographic technique that permits visualization of the coffin joint. It is also important to be able to visualize the fracture completely to evaluate the possibility that there is comminution near the toe. CommentsThe foot needs to be cleaned and the sole packed with a material of similar density to the hoof wall prior to radiography. Packing the sole removes the multiple radiolucent lines cast by the sulcus of the frog that can be confused with radiolucent fracture lines.The figures illustrate packing of the sole using a children modeling clay (plasticine). CommentsThe cassette is placed in a holder with a radiolucent top for the DP view.The figures illustrate the positioning of the foot on the protected cassette.
