L5 or Fifth Vertebra, Inferior View

Description

Inferior inspection centers on the axis (C2) vertebra, dominated by the dens (processus odontoideus) projecting superiorly from the vertebral body and bordered posterolaterally by the superior articular facets that receive the atlas (C1). Laterally, the transverse processes extend from the vertebral arch and frame the transverse foramina, while the pedicles and laminae complete the ring around the vertebral foramen. Posterior elements converge toward the spinous process, which sits in the midline, posterior to the canal. Spatial orientation is clear: dens anterior, laminae and spinous process posterior, transverse processes lateral. Rotation lives here. The atlanto-axial complex depends on the dens as the pivot for head turning, stabilized by the transverse ligament of the atlas and the alar ligaments, and this inferior perspective helps explain why disruption of those restraints can convert normal rotation into instability. Odontoid fractures (Type II at the base of the dens) and traumatic atlanto-axial subluxation are common teaching correlations, and both have high stakes because the spinal cord lies immediately posterior within the vertebral foramen. Surgical planning often references the relationship between C2 pedicles, pars interarticularis, and the transverse foramen, since C1 to C2 fixation risks vertebral artery injury if screw trajectories encroach laterally. Use this illustration in gross anatomy and neuroanatomy courses when teaching cervical vertebra identification, atlanto-axial biomechanics, and the bony boundaries of the spinal canal. It also suits radiology and trauma publications correlating CT appearances of dens fractures with stabilization options and ligamentous injury patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.