MORPHOLOGICAL AND MORPHOMETRIC STUDY OF FORAMEN MAGNUM IN CADAVERIC SKULLS AND ITS CLINICAL IMPLICATIONS IN NORTHERN PAKISTANI POPULATION

ABSTRACT
Aims and objectives: To study the different shapes of foramen magnum and to evaluate the anteroposterior, transverse
diameters and foramen magnum index in adult male cadaveric skulls in northern Pakistani population.
Materials and Methods: A total of 47 human adult dry skulls from the bone banks of Anatomy Departments were examined
and numbered. Different shapes of foramen magnum were classified. The anteroposterior and the transverse
diameter were measured. From these dimensions the average foramen magnum index was calculated.
Results: In 25.5% the FM was noted to have egg shape, in 21.3% it was oval shape, in 17% was tetragonal, in 14.9%
was pentagonal shape, in 10.6% it was hexagonal, in 6.4% it was round shape and in 4.3% of the total cases it was
irregular shape. In 6 (12.8%) of the cases the occipital condyle was noted to protrude into the FM. The mean AP diameter
was noted as 35.5 ± 3.4 and TD of the FM was noted as 31.9 ± 1.4 mm. The average FM index (AP divided