Spinal cord

Cross-section through cervical spinal cord.
Spinal Cord Tracts

The spinal cord is a bundle of nerves that go to and from the brain. It is enclosed in and protected by the bony vertebral column. The main function of the spinal cord is transmission of neural inputs between the periphery and the brain.

Spinal cord segments

Humans have 31 left-right pairs of spinal nerves, each roughly corresponding to a segment of the vertebral column. The spinal nerve emerges from the spinal column through an opening between adjacent vertebrae. Outside the vertebral column, the nerve divides into branches.

The nerves for incoming sensory information are bundled separately from nerves for outgoing motor instructions for muscles. The system serves the autonomic nervous system as well as the motor activities which we control consciously.

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