Experimental investigations of fractures of the upper thyroid horns

Fractures of the upper thyroid horns are a frequent finding after a variety of neck injuries - resulting from a direct mechanical trauma, e.g. compression of the neck in manual strangulation or ligature strangulation, from blunt injuries (falls or blows against the neck), and sometimes from indirect trauma (whiplash-injuries). Although it is well known that thyroid horns can be broken with relatively little pressure, no quantitative data are available in the literature. In an experimental investigation, the isolated thyroid cartilage was prepared (divided into two parts, measured, X-rayed, photographed, embedded in paraplast) and clamped in a simple apparatus. Weight was applied on the upper thyroid horn (imitating pressure on the horns), beginning with 1 kg and gradually increased by increments of 250 g to a maximum of 8 kg, until an 'injury' occurred. In this study, 120 thyroid cartilages (77 men, 43 women, 16-95 years) were investigated. The location of the fractures was in nearly all cases the base of the horns. The mean weight resulting in an injury of the horn was 3 kg (men: 3.3 kg, women: 2.6 kg). The required weight was dependent on the degree of ossification. The highest rate of fractures was found in cases with incomplete ossification; in cases without ossification, specimens often remained macroscopically uninjured.