Section of the Spinal Cord Showing the Nerve Roots

Description

Shown in transverse section, the spinal cord is cut to reveal the H-shaped gray matter with posterior (dorsal) horns positioned dorsolaterally and anterior (ventral) horns projecting anterolaterally, surrounded by circumferential white matter columns (funiculi). Yellow dorsal (posterior) nerve roots approach the cord along the posterolateral sulcus, while ventral (anterior) roots exit from the anterolateral surface; the two converge laterally to form the mixed spinal nerve. Spatially, the dorsal roots lie posterior to the ventral roots and typically appear slightly more superior in the field before joining. This cross-sectional relationship is the core teaching point for segmental neuroanatomy: sensory afferents enter via the dorsal root to synapse in the dorsal horn, while motor efferents arise from anterior horn cells and exit via the ventral root. Clinically, it maps directly onto radiculopathy and root-level lesions, where a posterolateral disc herniation compresses a spinal nerve or root to produce dermatomal pain and weakness that respects myotomes, and it also clarifies why dorsal root ganglion involvement shifts symptoms toward sensory loss and neuropathic pain. Clean anatomy. No guesswork. Use this plate to anchor lectures on spinal cord organization (gray versus white matter, dorsal versus ventral horns), to accompany neurology and neurosurgery chapters discussing spinal nerve root compression, and to illustrate anesthesia education on neuraxial blocks and the structures traversed near the intervertebral foramen. It also works well in exam-prep resources that test lesion localization by horn, root, or mixed spinal nerve patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.