This project tested several processing methods on a sample of 40 donated human thyroid cartilages obtained through an anatomical supply company.
The thyroid cartilage is the uppermost cartilage in the human larynx. Thyroid cartilage supports and protects the vocal cords as well as provides an attachment site for the hyoid bone via the thyrohyoid membrane. In forensic contexts, visible abnormalities on the thyroid cartilage may be indicative of perimortem trauma including ligature marks or stab wounds. During autopsy, the thyroid cartilage must be freed of surrounding soft tissue before these marks can be clearly observed; however, there is scant information on best practices for processing the thyroid cartilage. In the current project, three main processing methods were utilized: (1) dermestid beetles; (2) heat maceration (160 degrees F); and (3) chemical maceration with 300 mL solutions of laundry detergent, sodium borate, bleach, multi-purpose cleaner, and papain. A 19-point scoring system adapted from Steadman and colleagues (2006) was used to test the efficacy of each maceration method. The scores are based on odor (0-3), soft tissue texture (0-3), ease of soft tissue removal (0-5), cartilage quality (0-5), and duration (0-3). Methods receiving a higher point score were deemed better, since they performed well in multiple categories. With a final score of 18/19 (94.7 percent), chemical maceration using bleach was found to be the best method for removing the surrounding tissue from the thyroid cartilage. The recommended bleach method is inexpensive, quick, and requires almost no additional mechanical removal of soft tissue. (publisher abstract modified)