A 16-year-old male was transported to our emergency department after he was kicked in the abdomen by a horse. He was diagnosed with injury of the liver and abdominal rectus muscle, and was cured by observational treatment. An Ichushi search was undertaken to identify articles published from 1983 to 2013 using the key words "horse" and "trauma". We found 13 cases that described horse-related injuries and summarized these cases, including our case. There were 10 males, three females and one patient of an undescribed sex. The patients ranged in age from 16 to 58 years old, with an average age of 33 years. The injured sites were predominantly the face (mandible) and upper abdomen, indicating that a projecting part of the body may be more likely to be injured. Cardiac rupture, aortic head injury, or lethality induced by a horse kick have not been reported in Japan, but such injuries have been reported in other countries. Ten of 15 cases (67%) required surgical treatment for severe injuries. Horse kick injuries tend to be severe, because the transfer of energy from the end of the hoof, with a small cross-sectional area, to a small field, leads to internal organic injuries that are more severe than predicted, similar to a handlebar injury. Accordingly, we advocate the close observation of patients with horse kick injuries, which may be regarded as being similar to blunt stab wounds or hidden speared injuries.
Keywords: Handle bar injury; hidden speared injury; horse kick injury; liver injury; observation.