Fractures of the distal phalanx (also known as P3 or the coffin bone) are common, especially in racehorses, noted Tara S. Rabuffo, DVM, of the University of Pennsylvania’s New Bolton Center. She and her colleagues reviewed case records and all related diagnostic materials on 73 racehorses (26 Thoroughbred and 47 Standardbred during an 11-year period) admitted to the George D. Widener Hospital for Large Animals from Jan. 1, 1990, through Dec. 31, 2001.

“Fractures of the equine distal phalanx may be a form of stress-related bone injury much like other fractures in the racehorses,” Rabuffo reported. “Early scintigraphic examination of racehorses with palmar foot pain may identify stress-related bone injury before fracture and allow corrective shoeing to be instituted. These fractures most commonly occur in the lateral (outside) aspect of the left forelimb and the medial (inside) aspect of the right forelimb. Despite the fact that this injury can lead to osteoarthrits of the distal interphalangeal joint, there is a favorable prognosis for return to racing