Ossification of laryngeal cartilages on lateral cephalometric radiographs.

This study was undertaken to identify the variations in the physiologic ossification of human laryngeal cartilages by evaluating the lateral cephalometric radiographs of healthy males and females referred to our facility. Lateral cephalometric radiographs of 359 patients (141 male and 218 female; ages 10 to 59 years) referred from various specialty clinics between April 1998 and March 2000 were used. Frequencies and confidence intervals were obtained and tabulated for both thyroid and cricoid ossifications as seen on these cephalometric radiographs. The interobserver agreement was strong for both thyroid (kappa = .986) and cricoid (kappa = .982) observations. Overall, thyroid cartilage was more frequently ossified compared with cricoid. Various degrees of thyroid and cricoid cartilage ossification were found in 186 patients (120 female and 66 male) in the third decade and beyond. Among 173 patients in the first 2 decades (98 females and 75 male), evidence of thyroid ossification was found in 2 male patients aged 14 and 18, and ossification was detected in the cricoid cartilage in 12 patients. There was a preponderance of laryngeal cartilage ossification in men compared with women. Radiographically detectable laryngeal ossification increased with age starting in the third decade. There is a general trend of increase in the ossification of laryngeal cartilages as the age advanced.