Fifth Lumbar Vertebra L5, Posterior View

Description

Arising at the lumbosacral junction, the fifth lumbar vertebra (L5) is presented in posterior aspect with the spinous process centered in the midline and formed by union of the right and left laminae. Lateral to the laminae, the superior and inferior articular processes mark the zygapophysial (facet) joints, while the transverse processes project laterally as broad levers for the deep back musculature. Inferiorly, the sacrum sits directly beneath L5, its median sacral crest aligned with the lumbar spinous processes, and the coccyx continues distally in the midline. Posterior L5 anatomy matters because this vertebra carries the highest shear forces in the lumbar spine and interfaces with the sacrum at a segment commonly involved in degenerative disease. The orientation of the L5 to S1 facet joints helps resist anterior translation, so changes here correlate with L5 to S1 spondylolisthesis, pars interarticularis stress fractures, and facet arthropathy that can refer pain to the buttock. Clear visualization of the laminae and spinous process also supports procedural planning for midline posterior approaches, including laminectomy, decompression, and pedicle screw trajectories that begin just lateral to the superior articular process. Use this asset in gross anatomy teaching on the vertebral column, in orthopaedic and neurosurgical training materials covering posterior lumbar approaches, and in radiology correlation pieces explaining how posterior bony landmarks relate to axial CT and MRI at the L5 level. It also fits patient education modules on low back pain where showing the lumbosacral junction and sacrum in one frame reduces confusion. Anatomical accuracy verified by SciePro's Medical Advisory Board.