A key feature of spinal cord structure is that it consists of a continuous series of repeating segments.1 Each of these segments performs the same basic types of sensory processing, and contain the same basic circuitry, but they differ in the region of the trunk and limbs that they innervate.1 Each segment gives rise to a pair of spinal nerves that receive and send signals to different regions of the body1
There are 31 segments of the spinal cord grouped into regions:134
- 8 cervical (C1–C8): head, neck, arms, hands, and diaphragm
- 12 thoracic (T1–T12): chest and upper abdominal muscles
- 5 lumbar (L1–L5): lower back, hips, thighs, and knees
- 5 sacral (S1–S5): pelvic organs, legs and feet
- Below the sacral area there is the coccyx that is innervated by the single coccygeal nerve
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