First Lumbar Vertebra (L1), Gross Anatomy

Description

Centered on the first lumbar vertebra (L1), the model presents the vertebral body anteriorly with the vertebral arch posteriorly, where the thick laminae meet at the base of the spinous process and frame the vertebral foramen. Stubby transverse processes project laterally from the junction of pedicle and lamina, while the superior and inferior articular processes sit posterolaterally to define the zygapophysial (facet) joints with T12 above and L2 below. Adjacent intervertebral discs are rendered in white, separating the vertebral bodies in the lumbar segment and leading inferiorly toward the sacrum and coccyx. L1 is a transition-level vertebra, and that context matters: its facet orientation begins the shift from thoracic coronal facets toward the sagittal lumbar pattern, influencing flexion and rotation mechanics and the way pain localizes in upper lumbar facet arthropathy. The stout lamina and robust posterior elements are key landmarks when teaching posterior approaches to the spinal canal, and they help explain why upper lumbar decompressions demand respect for canal dimensions, ligamentum flavum attachments, and the relationship of the pedicles to the exiting nerve roots. Expect this asset to fit cleanly into gross anatomy and osteology teaching, where learners need to distinguish L1 from thoracic vertebrae (no costal facets) and from lower lumbar levels (larger bodies and different process proportions). It also supports clinical education in orthopedics, neurosurgery, physiatry, and radiology, pairing well with modules on vertebral fracture morphology at the thoracolumbar junction, pedicle screw trajectories, and level identification on CT or fluoroscopy. Anatomical accuracy verified by SciePro's Medical Advisory Board.