ABSTRACT
Variations in the number and size of the foramina transversaria of cervical vertebrae are commonly observed during cross sectional imaging examinations. This study while designed to investigate the magnitude and types of such diversities of the normal morphology, attempts to associate variations to anatomical and developmental criteria. Thirty sets of dry cervical vertebrae belonging to adult subjects were selected randomly for this study. For each vertebra the foramen transversarium was examined for its number and area. There was no significant statistical difference between the area of the right and left foramina transversaria in all cervical vertebrae. C1 foramen transversarium was the largest while C7 foramen transversarium was the smallest. Accessory foramina transversaria were mostly observed in the lower cervical vertebrae [C5, C6 and C7] mostly in C6 [70% have accessory foramina]. The multiplicity of the foramina was a single vertebral feature rather than a general phenomenon in the same subject. It seems that many factors are involved in causing the morphological variations of the foramen transversarium including developmental factors, mechanical stress, the size, and/or the number of anatomical structures passing through