Ossification of the laryngeal cartilages as it relates to computed tomography.

Ossification of adult laryngeal cartilages was studied using cross sections cut in planes parallel to those used in computed tomography (CT). The percentage of ossification of surfaces of thyroid laminae was calculated and marked variations were found. There was no correlation between ossification and age (all subjects were 50 years or older). Generally, laryngeal cartilages of men were ossified to a greater extent than those of women. Some male cartilages were only slightly ossified, however, while some female cartilages were nearly completely ossified. Inner and outer surfaces of thyroid laminae differed by as much as 35% in some cases. Left and right laminae showed even greater differences, indicating that symmetry of ossification is not the rule. Ossification of arytenoid and cricoid cartilages also varies. This study reveals that there is no reliable pattern of ossification of laryngeal cartilage that would be of use the radiologist in evaluating CT scans for invasion of cartilage by cancer.