Vertebral Artery Groove Of Atlas, Posterior View

Description

Atlas (C1) is presented from a posterior perspective, centering on the sulcus arteriae vertebralis (vertebral artery groove) along the superior surface of the posterior arch just lateral to the posterior tubercle. The groove curves posterior to the superior articular process and medial to the lateral mass, where it leads toward the transverse foramen that transmits the vertebral artery with its accompanying venous plexus and sympathetic fibers. Superior articular facets sit anteromedial to the groove, while the posterior arch forms the bony roof beneath the vessel’s usual course. Bony landmarks read at a glance. Surgeons and radiologists care about this sulcus because its depth and bony margins vary, and the groove may be bridged by ossification of the posterior atlanto-occipital membrane to form an arcuate foramen (ponticulus posticus), a frequent anatomic variant that can complicate C1 lateral mass screw placement and posterior arch exposure. Fractures of the posterior arch (including Jefferson-type ring injuries) and congenital hypoplasia also change the relationship between bone and the vertebral artery, raising the stakes during posterior cervical fixation and when interpreting CT angiography in trauma. The fixed posterior viewpoint gives a direct read on where the artery lies relative to the superior articular process and posterior arch, which is the relationship that matters in most posterior approaches to C1. Use this illustration in upper cervical spine modules for gross anatomy, neurosurgery, orthopaedics, or radiology, and in publications covering atlantoaxial instrumentation, vertebral artery injury risk, and anatomic variants of the atlas. It also fits well in patient-facing surgical consent materials where a single posterior atlas image can explain why vertebral artery proximity limits hardware trajectories. Anatomical accuracy verified by SciePro's Medical Advisory Board.