The reliability and forensic soundness of the equine shin circumference measurement in living animals versus post‑mortem examination.

Catastrophic injuries in racehorses mostly involve the metacarpal region. Although many studies describe fractures of equine limbs, few examine the relationship between bone morphometrics and musculoskeletal problems in racing horses. And yet, according to the regulation of some Italian traditional races, the shin circumference represents a qualifying prerequisite for horses to be admitted to races. This study aims to evaluate the conformity of the shin circumference measurement in living animals and in post‑mortem examinations, in order to evaluate the forensic reliability of these measurements. The right and left distal forelimbs from 11 horses of 5 different breeds were examined. The shin circumference was measured at 3 time points: in the living animal before slaughter/euthanasia, 5 hours post‑mortem, and after 14‑days of cold storage. The isolated limbs were also weighed in both of the post‑mortem examinations. In the examined sample, the mean shin circumference was 24.0 ± 2.4 cm in living animals, 22.9 ± 2.5 cm 5 hours post‑mortem, and 22.4 ± 2.3 cm after 14‑days of cold storage, with a highly significant difference between these measurements (P < 0.001). There was also a significant decrease in the limbs' weight between the 2 post‑mortem examinations (P < 0.001). According to our findings, the post‑mortem measurement significantly underestimates the in vivo dimensions of the shin circumference, even when performed a few hours after death; the forensic soundness of this parameter is therefore limited.