The constancy of the number of cervical vertebrae in mammals is probably the result of selection against associated variations. A survey among patients with and without cervical ribs showed an association between miscarriage and the presence of cervical ribs. This supports the hypothesized selection against variations in cervical vertebral number.

Cervical rib, Miscarriage, Reproduction, Thoracic outlet syndrome,
Early Human Development
Department of Gynaecology & Obstetrics

Schut, P.C. (P. C.), Eggink, A.J, Cohen-Overbeek, T.E, Van Dooren, T.J.M. (T. J.M.), de Borst, G.J, & Galis, F. (F.). (2020). Miscarriage is associated with cervical ribs in thoracic outlet syndrome patients. Early Human Development, 144. doi:10.1016/j.earlhumdev.2020.105027