Introduction: The knowledge about the diameter of head of femur is essential for orthopaedic surgeons in selecting prosthesis for hip replacement surgeries. It also helps radiologists in diagnosing various conditions like Perthes disease. This knowledge about the diameter of head of femur in both sexes also helps the anatomists and forensic experts. Aim: Determination of mean values of Femoral Head Diameter. Materials and Methods: Normal plain radiographs of pelvis with bilateral hip joints – AP view of both males and females between the 20 to 50 years of age were used for study. A total of 200 x-rays (100 males and 100 females) were included in the study. Inclusion criteria: a) Patients complaining of pain in hip, who had no joint pathology defined on the basis of radiological examination b) Patients of age group 20-50 years. c)Patients without any deformity of hip joint. Exclusion criteria: a)Patients having history of pathologies like Osteoarthritis, Tuberculosis, Fractures around hip joint. b) Patients having history of Surgical intervention around this area. Observations: The mean Femoral head diameter of all the 200 xrays on the right side was 47.24 mm with the standard deviation of 3.63 mm. While on the left side it was 46.13 mm with the standard deviation of 3.97mm. The overall mean femoral head diameter in 100 radiographs of males on the right side was found to be 49.17 +3.75 mm (44 – 53mm) while on the left side it was found to be 47.96 + 4.53mm (43 – 51 mm). In case of females, the mean femoral head diameter in 100 radiographs on right side was found to be 45.32 + 3.52 mm (41 – 52 mm) while on the left side it was found to be 44.34 + 3.31 mm (41 -50 mm). Conclusion: The results calculated provides important information regarding gender and side variations of Femoral head diameter for the radiologists, orthopaedic surgeons, anatomists and forensic experts. The data thus obtained can be used as a baseline for further studies in the departments of Anatomy, Radiodiagnosis and Orthopaedics.

Femoral Head Diameter, Prosthesis, Hip replacement surgeries.