MORPHOMETRY AND SEXUAL DIMORPHISM IN FORAMEN MAGNUM: A STUDY OF HUMAN SKULL BONES
Address for Correspondence: Dr Vinutha. S.P, Assistant Professor, Department of Anatomy, JSS Medical College, Mysuru 570015, Karnataka, India. Mobile No: +919481155140, +919916372652 E Mail: drvinutha.sp@gmail.com Background and Objectives: The foramen magnum is a fundamental component in the interaction of bony, ligamentous and muscular structures composing the craniovertebral junction. The measurements of the foramen magnum have a crucial importance in surgical resection and thereby reaching the lower clivus and premedullary region in transcondylar approach. The objectives of the present study are to find out the shape and dimensions of foramen magnum in human skull bones. Materials and Methods: The study sample comprised of 200 skull bones (100 males and 100 females) of south Indian origin. Measurements were taken using sliding vernier calipers. The parameters were noted meticulously and the statistical analysis for sex comparison was made by student's t test and was considered significant whenever p 0.05. Results: The Foramen magnums were classified into 8 types based on shape. Commonest being oval and pentagonal was the least common type. The mean APD of FM in male and female skull bones were found to be 33.37 mm 2.33 and 29.72 mm 1.89 respectively. The mean TD of FM in male and female skull bones were found to be 27.40 mm 2.44 and 24.73 mm 2.05 respectively. The mean circumference of FM in male and female skull bones was found to be 102.58 mm 4.68 and 92.65 mm 4.37 respectively. The area of the FM was calculated using three different formulas. The mean area 1 of FM in male and female skull bones was found to be 718.41 mm2 83.75 and 577.52 mm2 64.36 respectively. The mean area 2 of FM in male and female skull bones was found to be 727.50 mm2 83.12 and 583.71 mm2 63.58 respectively. The mean area 3 of FM in male and female skull bones was found to be 838.77 mm2 75.94 and 684.36 mm2 64.10 respectively. All parameters were significantly greater in males than in females (P<0.001) Conclusion: The data obtained may be useful to the neurosurgeon in analyzing the morphological anatomy of the craniovertebral junction. The findings are of particular interest in anthropology, anatomy, forensic medicine and other medical fields.