Cervical enlargement

The cervical enlargement of the spinal cord is a region where the spinal cord becomes noticeably wider to accommodate the increased number of nerves needed to supply the upper limbs.

Location:

The cervical enlargement is located in the cervical region of the spinal cord, specifically between the C3 and T2 spinal segments. This corresponds roughly to the lower neck and upper thoracic area. It reaches its maximum width at the C5 segment.

Why does the spinal cord enlarge here?

The cervical enlargement happens because this region must house more motor neurons and sensory neurons in the ventral and dorsal horns of the spinal cord gray matter. These neurons control the muscles (motor function) and relay sensations (sensory function) for the shoulders, arms, and hands. The spinal nerves that emerge from the cervical enlargement contribute to the brachial plexus, which is a network of nerves responsible for innervating the upper limbs.

A similar swelling, the lumbar or lumbosacral enlargement, is located in the lower part of the spinal cord and supports the lower limbs. It is associated with the lumbar plexus.