Trauma Survivors Network - provided by ATS

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A Program of the ATS

Spinal Cord Injuries_Anatomy and Physiology

The spinal cord is the organ that allows the brain to communicate with the rest of the body. It is responsible for sensation and movement, so when the spinal cord is injured, it can affect a patient’s ability to both feel and move. The spinal cord is protected by a bony structure known as the spine and the spinal cord is divided into 31 different segments which include:
  • 8 cervical (neck) segments
  • 12 thoracic (mid-back) segments
  • 5 lumbar (low-back) segments
  • 5 sacral (pelvis) segments
  • 1 coccygeal (tail-bone) segment

Cervical spinal nerves (eight pairs) supply the back of the head, the neck and shoulders, the arms and hands, and the diaphragm (muscle of respiration). Thoracic spinal nerves (twelve pairs) supply the chest, some muscles of the back, and parts of the abdomen. Lumbar spinal nerves (five pairs) supply the lower parts of the abdomen and the back, the buttocks, some parts of the external genital organs, and parts of the legs. Sacral spinal nerves (five pairs) supply the thighs and lower parts of the legs, the feet, most of the external genital organs, and the area around the anus.

These four groups of nerves that branch from the cervical, thoracic, lumbar, and sacral regions of the spinal cord are called the peripheral nerves. The peripheral nervous system services the limbs and organs of the body and is located outside of the central nervous system. The peripheral nervous system is further divided into the somatic, associated with voluntary actions via skeletal muscle, and autonomic nervous system, that is involved with unconscious actions such as blood flow, digestion, and temperature regulation.