Which enlargement is associated with the upper limbs?

Which enlargement is associated with the upper limbs?

• A. Cervical
• B. Thoracic
• C. Lumbar
• D. Sacral

Answer: (A)

The upper limbs rely on nerves that originate from the cervical levels of the spinal cord, especially from C5 through T1. This region is an enlargement because it contains a larger pool of motor neurons that supply arm, forearm, and hand muscles, and it forms the brachial plexus that gives rise to the major nerves of the upper limb. In contrast, the lumbar enlargement serves the lower limbs, and the thoracic region mainly handles trunk muscles with no need for a big neuronal pool for limbs, while the sacral area contributes to nerves of the lower body as well. So the enlargement associated with the upper limbs is the cervical enlargement.

The upper limbs rely on nerves that originate from the cervical levels of the spinal cord, especially from C5 through T1. This region is an enlargement because it contains a larger pool of motor neurons that supply arm, forearm, and hand muscles, and it forms the brachial plexus that gives rise to the major nerves of the upper limb. In contrast, the lumbar enlargement serves the lower limbs, and the thoracic region mainly handles trunk muscles with no need for a big neuronal pool for limbs, while the sacral area contributes to nerves of the lower body as well. So the enlargement associated with the upper limbs is the cervical enlargement.