Answer

The L4 nerve root exits the spinal canal below its numbered pedicle (here) It traverses the disc space above and here it is prone to compression by a posterolateral disc protrusion at L3/4.

Feature to be able to label

• Vertebral body (with its superior and inferior endplate)
• Spinal canal (conveying the neural elements)
• Pedicles
• Lamina
• Transverse processes
• Superior articuar facet
• Spinous process
• Inferior articular facet
• Pars interarticularis (between the lamina and the pedicle) – site of a spondylolysis – pars defect
• Intervertebral foramina