Aim:The aim of this study was to investigate the size and variations of the foramen transversarium (TF). In addition, to study the anatomical variations of vertebral artery entering the transverse foramen of the cervical vertebrae.Material and Methods:The images of 141 (90 males, 51 females) patients aged between 18-79 years (mean: 52.7 years) were analyzed. As a result, 987 cervical spines (C1-C7) and 1974 foramen transversariums were individually evaluated. Each FT’s anterior-posterior (AP) and transverse diameter was measured bilaterally from multidetector computed tomography (CT) images.The absence of TF as agenesis and a diameter of less than 2 mm was considered to be hypoplastic. Double foramina and incomplete double foramina were also noted. We evaluated the levels at which the vertebral arteries entered the transverse foramina.Results:TThe most frequent variation was duplication of TF, which was noted in a total of 88 (8.91%) cervical vertebrae. Agenesia of TF was seen in 37 (3.74%), and hypoplasia of TF was seen in 26 (2.63%) cervical vertebrae. The vertebral artery entered into the transverse foramen of the 5th cervical vertebra from both sides in 4 (1.84%) patients. The vertebral artery entered into the transverse foramen of the 7th cervical vertebra in 4 (1.84%) patients. The vertebral artery entered into the transverse foramen of the 4th cervical vertrebra in only 1 (0.45%) patient. Conclusion:We believe that the determination of foraminal variations could be an important guide for neurosurgeons and radiologists in the diagnosis and treatment of diseases in this area.