What part of the spinal cord represents an increase in cell body mass for upper limb control?

a. cervical enlargement.

b. lumbar enlargement.

c. conus medullaris.

d. cauda equina.

Answer: a. cervical enlargement.

Explanation:

Cervical enlargement corresponds to the enlargement of the spinal cord. The spinal cord is the origin of the spinal nerves that contribute to an important task of supplying blood to the upper limbs.

The cervical enlargement results in an increase in the volume of the motor cells in the ventral part inside the grey matter. The motor neurons which are sited posteriorly supply to the upper limbs. Those which supply to the distal muscles are situated further posteriorly.

The correct answer is - option A. cervical enlargement.

Explanation:

The cervical enlargement is one of the two spinal enlargements which corresponds with the supply of large nerves, the upper limbs. It initiates from the 5th cervical to the first thoracic vertebra.

It is the region of the spinal cord that represents a swelling in the cell body mass for the upper limb. The spinal cord has an increase in the cervical region which is referred to the cervical enlargement,

Thus, the correct answer is option - a. cervical enlargement.