Cervical vertebrae are characterized by the presence of foramen transversarium through which passes vertebral artery, vein and sympathetic nerves. In some percentage of cervical vertebrae we there are additional foramen called accessory foramen transversarium. These may be present unilaterallyor bilaterally.

These are foramena found in the cervical vertebrae other than the transverse foramenae. Sangari et al (2015) reported incidence of 24% (http://dx.doi.org/10.1155/2015/391823) while Murlimanju et al (2011) reported incidence of 1.6% (https://doi.org/10.5137/1019-5149.JTN.4047-10.0).