Surgical Anatomy of the Anterior Cervical Spine: The Disc Space, Vertebral Artery, and Associated Bony Structures

In reply: Our article presents the study of the surgical anatomy of the anterior cervical spine, including the disc space, vertebral artery, and associated bony structures. Our objective was to study the relationships among these important neurovascular structures and the surrounding bone. The study was designed to determine the exposure of important vascular structures after interbody distraction of the vertebral bodies after discectomy. The second part (pars transversaria) of the vertebral artery was considered in our study. That part of the artery extends from the transverse foramen of the lower cervical vertebrae to the transverse foramen of the axis(C2). The vertebral artery enters the transverse foramen of C7 in 2%, C6 in 90%, C5 in 5%, C4 in 2%, and C3 in 1% of the cases (1). Our diagram (Fig. 2, p 771) is not incorrect. It displays one of the possible levels of entrance of the vertebral artery into the transverse foramen, and it was our intention to outline the lowest possible entrance of the artery into the foramen. A surgeon must always approach the foramen with great caution, regardless of the frequency with which an artery courses through it. Our study demonstrated that with distraction, important vascular structures can be at risk. We mentioned neither the course nor the relationship of the first part(pars prevertebralis) of the vertebral artery in the thoracic outlet. That section of the vertebral artery is not within the transverse foramina of the cervical spine nor was it part of our study. T. Glenn Pait Kenan I. Arnautovic Little Rock, Arkansas