Anaphysio

ANATOMY AND PHYSIOLOGY OF THE SPINAL CORD

Even though the brain controls the activities of the whole body, it only extends down to the top of the neck. Below that, the spinal cord carries messages between the brain and your body. Your face has a direct connection to the brainstem, so it is independent of your spinal cord.

The spinal cord looks like a long rope about the width of your little finger. It runs from the base of your brain down to the lower part of your back, and it is fragile. Spinal cord injury [SCI] can lead to loss of movement and feeling. It can also affect how your brain controls your internal organs. When your spinal cord is injured, parts of your body below the level of the injury are affected.

The spinal cord is protected by your backbones [your spine]. The backbones are 29 small bones stacked on top of each other. These bones are called vertebrae. To allow your back to bend and to lessen jarring, each vertebra is cushioned from the next by disks. Disks are made of a spongy material and act like shock absorbers. Ligaments hold the vertebrae together and allow your neck and back to twist and bend.

Each vertebra has a hole in it—a hard, bony tunnel through which the spinal cord passes. This is the spinal canal. It protects the spinal cord from damage. The vertebrae and disks, held together by ligaments, are called the spinal column.

Your spine has four sections. The top is the cervical section, which is your neck. The next down is the thoracic section, which extends from your lower neck to your lower ribs. The lumbar section is your lower back, and the sacral section is your tailbone. Your sacral section is really only one bone, with five nerve pairs coming out through holes in it.

The cervical section contains eight pairs of nerves and seven vertebrae. The nerves numbered C1 through C7 exit from the spine above the corresponding numbered vertebrae, and the C8 nerve pair exits between the C7 and T1 bones on each side. For the thoracic and lumbar...