577 Ankit et al., Int J Med Res Health Sci. 2013;2(3): 577-581 International Journal of Medical Research & Health Sciences www.ijmrhs.com Volume 2 Issue 3 July - Sep Coden: IJMRHS Copyright @2013 ISSN: 2319-5886 Received: 29 th Apr 2013 Revised: 28 th May 2013 Accepted:13 th Jun 2013 Research Article A STUDY OF SEXUAL DIMORPHISM IN HUMAN STERNA *Adhvaryu Ankit V, Adhvaryu Monika A, Rathod Suresh P, Chauhan Pradip R, Joshi Hemang G Department of Anatomy, P.D.U. Medical College, Rajkot, Gujarat, India *Corresponding author email: ankit_adhvaryu@yahoo.co.in ABSTRACT In the present study, 100 human, dry adult sterna, 45 male and 55 female, from various medical colleges of Saurashtra region of Gujarat were measured for length of manubrium, length of mesosternum and combined length of manubrium and mesosternum. The data was statistically analysed for mean, standard deviation and p value. “The Rule of 136” given by Ashley (1956) was applied to determine the sex of sterna and to determine the number of male and female sterna obeying the rule. Statistically significant difference in mean values of length of manubrium, length of mesosternum and combined length of both sexes was observed. “Rule of 136” determined 34 male and 66 female sterna, while 71.11% (32) of male sterna and 96.34% (53) of female sterna obeyed the rule. It concluded that of all the three parameters measured, combined length of manubrium and mesosternum was the best discriminating parameter of sex and Rule of 136 was helpful in determination of sex. Keywords: Human Sternum, Combined length of manubrium and mesosternum, Rule of 136 INTRODUCTION Sex determination from unknown human skeletal remains or decomposed bodies is an important initial step in forensic investigation 1 . Experts are always facing a problem in identifying whether the skeletal remains are human or not as well as estimation of correct age and sex of specimen available 2 . Accurate determination of skeletal sex has been a critical issue in medicolegal cases and the accuracy depends on the nature of material available and methods applied 1 . The human sternum is a flat elongated shield of bone that forms the middle of anterior part of thoracic cage forming a and protects the inner vital organs 1 . Various studies have been carried out by various workers by using Sternum as an individual parameter of the determination of age and sex. The first work was done in 1788 by Wenzel 3 , who studied the ratio between the length of manubrium and that of mesosternum in both the sexes. Wenzel’s work lead to enunciation of Hyrtl’s law (1788) 4 which stated that the Manubrium-Corpus Index also now known as Sternal Index (M/B ×100) exceed 50 in females while it is less than 50 in males. This was followed by works to correlate the total length of Manubrium and mesosternum (M+B) with sex. Dwight (1890) 5 concluded from his study that combined length DOI: 10.5958/j.2319-5886.2.3.101