Determination of Stature from Anthropometric Measurements of Thyroid Cartilage in the Population of Punjab

The astonishing task of determining the identity of an individual has been simplified, with the innovation of scientific technologies like DNA fingerprinting in the developed countries. Yet the application of such advanced technologies in developing countries is still a daunting task due to its complexity. Anthropometric analysis for the identification of unknown bodies is reasonably productive owing to its inexpensiveness. The aim of this study was to correlate the anthropometric measurements of the thyroid cartilage with the stature of the individual. Thyroid cartilages from 300 post mortem cases done in native population of Punjab were studied anthropometrically. A total of seventeen anthropometric measurements of selected parameters of thyroid cartilage were defined, measured, and statistically correlated with the body length of the individual. The variables which were significantly correlating with the body length were further analysed by regression analysis for derivation of a regression equation.


Introduction
One of the most important duties of any forensic expert is to determine the identity of an unknown deceased and establishing the same from any dismembered part of body. Stature of an individual is an essential requirement for establishing the identity of the individual. Most of the previous studies have relied on the anthropometric measurements of long bones for identifying the stature of an individual. The various well defined anatomical features of thyroid cartilage are not only quantifiable as anthropometric measurements (1) but it also has an added advantage of being in a superficial anatomical location that negates the tedious removal and preparation process that must be done when utilising long bones for stature estimation. There are a few literatures (2)(3)(4)(5)(6) that It is a prospective analytical study conducted from July 2012 to December 2013 on 300 cases autopsied in the department of Forensic Medicine of a tertiary care hospital in Chandigarh. Written informed consent from the legal heirs of the deceased were taken.

Inclusion criteria
• All cases above the age of 18 years.
• Residents of Punjab having at least two generation of ancestors from Punjab.

Exclusion criteria
• Cases with injury to thyroid cartilage.
• Known cases of Kyphosis • Known cases of Scoliosis • Acromegaly.
• Congenital abnormalities of neck.
• Cases with advanced decomposition changes.
The recumbent length of the deceased was measured with the help of portable anthropometer after extending the neck, spine, and the lower limbs to overcome flexion due to rigor mortis. The body length was measured from vertex to the heel of the foot. To avoid inter observer error, the measurements were measured by three different observers and the mean value was taken. The thyroid cartilage was dissected out during autopsy, with great care as not to damage the superior and inferior horns in the process. The entire thyroid cartilage was then soaked in warm caustic soda solution until all muscular and ligamentous attachments sloughed off. After removal of all attachments, the dimensions of the thyroid cartilage were measured with the help of a thread, vernier caliper and goniometer. The recumbent body length and 17 parameters including the thyroid angle of thyroid cartilage were measured as per Table  1. All the parameters were measured by three observers and the mean value was taken as the final measurement to avoid inter observer error of measurement. All the analyses were carried out with the help of IBM SPSS Statistics package (version 20.0).

Results
A total of 300 samples of thyroid cartilages of the deceased belonging to Punjab population were collected and studied. Of these 300 samples, 238 were males and 62 were females. The length of body varied from 146 cm to 195 cm in males with a mean of 169.95 cm, mean standard deviation of 7.16 cm and standard error of 0.46. In females, body length ranged from 144 cm to 184 cm with a mean of 156.59 cm, mean standard deviation of 8.06 cm and standard error of 1.02. The length of body was compared and correlated with each of the seventeen variables using bivariate correlation analysis.

Discussion
Various studies, which analysed the anthropometric measurements of thyroid cartilage of males and females, found a significant difference between them and established that sex can be determined from anthropometric measurements of thyroid cartilage (7)(8)(9)(10)(11)(12)(13)(14)(15) . In the present study, the body length of the deceased was compared with various parameters of thyroid cartilage and it was found to be significantly correlating with length of right and left thyroid lamina for both gender. This finding was consistent with the studies conducted by Monica and Dhall (2) and Pierre Fayoux et al (3) . The study conducted by Monica and Dhall (2) also found a significant correlation between body length of individual with height of arch of cricoid cartilage and transverse diameter of cricoid cartilage. In the present study those anthropometric parameters were not measured. The study conducted by Pierre Fayoux et al (3) done on 300 human larynxes also found significant correlation with thyroid alar width, and median anterior thyroid height. Whereas the present study didn't find any correlation of body length with thyroid alar width and median anterior thyroid height. Too-Chung and Green (4) conducted a study in paediatric age group with 67 samples. They reported a linear correlation between body length with coronal and sagittal diameter at lower border of cricoid cartilage whereas the present study, the anthropometric parameters like coronal and sagittal diameter of lower border of cricoid cartilages were not evaluated. The study conducted by Schild (5) was conducted on human infant larynxes and found a linear correlation between crown rump length and the ventral thyroid height, but in the present study the parameter ventral thyroid height was not correlating with the body length. The study conducted by Ajmani et al (6) didn't find any correlation between various anthropometric measurements of thyroid cartilage and the body length of the individual. The deviations of the above study results from the present study might be due to variation in the definition of parameters studied, differences in the number of samples and age range of samples studied from the present study.

Conclusion
Significant correlations were found between length of both sides of thyroid lamina and body length in both gender. Regression equation for prediction of body length from length of right and left thyroid lamina was derived for each sex. With a sample of thyroid cartilage of known gender, one can estimate the body length of the individual using the regression formula we have derived. This regression formula uses only the major parameters of thyroid cartilage namely length of right and left thyroid lamina, which are less prone to be damaged in the process of recovery from the body compared to other parts of thyroid cartilage. Further studies need to be conducted in different population to derive a standard regression equation for estimation of stature from anthropometric measurements of thyroid cartilage for a native population.