Topic overview

Start with the big picture

The spinal cord extends from the foramen magnum to approximately the L1–L2 vertebral level, where it ends as the conus medullaris; the filum terminale and cauda equina continue below. Its 31 segments give rise to spinal nerves, while cervical and lumbar enlargements serve limb-related plexuses. Internally, dorsal, ventral, and lateral gray-matter horns are surrounded by white-matter funiculi. Ascending tracts convey sensory signals, including fine touch, pain, and proprioception; descending tracts contribute to voluntary movement, posture, and reflexes. The topic also connects these pathways with spinal blood supply, meninges, roots and ganglia, autonomic neurons, reflex arcs, and clinical syndromes. Dermatomes and myotomes provide a segmental framework for relating sensory and motor findings to spinal levels.