Background: Foramen Magnum is a large oval shaped opening in the posterior cranial fossa. It is a very important feature in bipeds. The knowledge of the dimensions and the shape of the FM has important clinical implication in prognosis and treatment of various neurological pathologies like Arnold-Chiari Syndrome and posterior cranial lesions. Morphometric parameters of FM are of great importance to Orthopaedician, Neurosurgeon, Radiologist and Anthropologist to achieve the best exposure with appropriate surgical outcome.