Atlas, Lateral View

Description

Profile orientation places the skull superior to the upper cervical spine, with the occipital condyles resting on the superior articular facets of the atlas (C1) at the atlanto-occipital joints. Laterally, the atlas is identified by its anterior and posterior arches, bulky lateral masses, and the transverse processes containing the transverse foramina, positioned lateral to the spinal canal and anterior to the posterior elements. The groove for the vertebral artery along the superior surface of the posterior arch sits posterolateral to the lateral mass, immediately inferior to the occiput. Inferior to C1, the axis (C2) aligns with the remaining cervical vertebrae, while the mandible, teeth, and temporomandibular joint occupy the anterior facial profile; the hyoid bone appears suspended anterior to the upper airway at approximately the C3 level. Lateral anatomy of C1 matters because many key stabilizers of the craniocervical junction are inferred from these bony landmarks, including the attachment sites for the transverse ligament of the atlas and alar ligaments, which constrain atlanto-axial rotation and prevent anterior translation of the atlas on the dens. Jefferson fracture patterns involve the anterior and posterior arches of C1 and can widen the lateral masses, while vertebral artery injury risk tracks closely with the transverse foramen and the posterior arch groove during C1 lateral mass screw placement. Small changes here have big consequences. This view keeps the relationships intuitive. Use this illustration for anatomy and radiology teaching on the craniovertebral junction, including correlation with lateral cervical spine radiographs, CT reconstructions, and surgical approaches to C1–C2 fixation. It also fits well in spine surgery atlases, trauma education on C1 ring fractures, and patient-facing materials explaining upper neck stability and head rotation mechanics. Anatomical accuracy verified by SciePro's Medical Advisory Board.