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The time of fusion of the sternebrae with one another was studied in sterna obtained from cadavers of 806 male and 212 female adults and 66 male and 29 female children, on whom medicolegal postmortem examinations had been conducted by the senior author. Sterna of 31 neonates were also studied. The bones were X-rayed in an anteroposterior view and later macerated, cleaned, and dried. The sternebrae fused with one another from below upwards. In both sexes, the third and fourth sternebrae showed partial or commencement of fusion in a majority of specimens in the 0-5 years age group. Although the earliest complete fusion was seen in the 6-10 years age group, 100% specimens exhibited complete fusion in the 15-17 years age group. The earliest complete fusion between second and third sternebrae was observed in the 11-14 years age group in both sexes; it was seen in 100% of specimens in males over 25 years and in females over 30 years. The first and second segments showed earliest complete fusion in a boy of 16 years and in a girl of 18 years; 100% of specimens showed complete fusion in the males over 60 years and in the females over 30 years. A mesosternum showing complete fusion of all the sternebrae must be from a subject over 16 years of age if male and over 18 years if female. These observations are at variance with those of workers in Western countries. There has been no other report from India on this subject.

Precise sexing--97% to 99% accuracy--of adult chest plates is possible when highly predictive costal cartilage ossification patterns are combined with four simple metric determinations. More than 1100 chest plate roentgenograms were evaluated for ossification pattern, fourth rib width, corpus width, sternal length and sternal area in an adult decedent population. An elementary, empirically obtained algorithm using the patternings and measurements, along with simple derivations (sternal length and area indices) was developed and then applied in chest plate sexing. This technique is not only easy, rapid and inexpensive, but it also results in a permanent and easily stored record.

For differentiating a male from a female sternum, a metrical study of 400 adult North Indian sterna (312 males and 88 females) obtained from medicolegal postmortems was made. If the combined length of the manubrium and mesosternum was more than 140 mm. the sternum was male, and if less than 131 mm. it was female. No opinion could be given if the length was between 131 and 140 mm. By this measurement 72.12% male and 62.50% female sterna could be sexed with 100% accuracy. The length of the mesosternum alone could also determine the sex correctly in 50.32% male and 29.55% female specimens. The length of the manubrium, manubrium-corpus index, width of the first or third sterebra or their index, were not found to be useful in sexing a given sternum. By using multivariate analysis the probability of correctly identifying the sex of a sternum was over 85%.