L4 Vertebra

Description

Centered on the lower lumbar column, the L4 vertebra is isolated in blue within a lateral view of L1 through L5 and the superior sacrum. From this profile, the L4 vertebral body sits anterior to the vertebral arch and posterior elements, with the spinous process projecting posteriorly and the transverse processes extending laterally. Superior and inferior articular processes are visible as stacked facet surfaces at the junction of pedicle and lamina, oriented to articulate with L3 above and L5 below. Intervertebral discs intervene between adjacent vertebral bodies, with L4 to L5 positioned immediately superior to the lumbosacral junction. A lateral perspective at L4 matters because it captures the segment where load transfer, disc shear, and facet constraint converge, and where degenerative change often becomes symptomatic. Disc height loss at L4 to L5 and hypertrophy of the L4 to L5 zygapophysial joints narrow the lateral recess and intervertebral foramen, a common anatomic substrate for L5 radiculopathy and neurogenic claudication. Facet orientation at this level also frames why degenerative spondylolisthesis most often occurs at L4 on L5, with anterior translation apparent relative to the sacral promontory. Use this artwork for gross anatomy and kinesiology teaching on lumbar motion segments, for spine surgery or interventional pain publications discussing L4 to L5 facet arthropathy and foraminal stenosis, or for patient education explaining why low back pain localizes near the lumbosacral junction. It also supports radiology correlations with lateral lumbar radiographs and sagittal CT or MRI, where disc space narrowing and facet degeneration are assessed in the same projection. Anatomical accuracy verified by SciePro's Medical Advisory Board.