The spinal cord is a slender cylindrical structure about the diameter of the little finger. The spinal cord begins immediately below the brain stem and extends to the first lumbar vertebra. Thereafter, the cord blends with the conus medullaris which becomes the cauda equina, a group of nerves resembling the tail of a horse. The spinal nerve roots are responsible for stimulating movement and feeling. The nerve roots exit the spinal canal through the intervertebral foramen, small hollows between each vertebra. The brain and the spinal cord make up the Central Nervous System (CNS). The nerve roots that exit the spinal cord/spinal canal branch out into the body to form the Peripheral Nervous System (PNS).
|Type of Neural Structure||Role/Function|
|Brain Stem||Connects the spinal cord to the brain.|
|Spinal Cord||Carries nerve impulses between the brain and spinal nerves.|
|Cervical Nerves (8 pairs)||Enables feeling and function to the head, neck, shoulders, arms, and hands.|
|Thoracic Nerves (12 pairs)||Enables feeling and function to organs and abdominal structures, muscles in the chest and back areas.|
|Lumbar Nerves (5 pairs)||Enables feeling and function to the lower back and legs.|
|Sacral Nerves (5 pairs)||Enables feeling and function to the buttocks, legs, feet, anal and genital areas of the body.|
|Dermatomes||Areas on the skin surface supplied by nerve fibers from one spinal root.|
The bony structures of each vertebral body form the hollow space where the spinal cord is located. Inbetween the vertebrae, at the left and right sides, a natural nerve pathway called the neuroforamen is formed. Nerve roots exit the spine through the neuroforamen. The nerve roots branch out to form the peripheral nervous system.