A dorsal and ventral root of each spinal segment unite to form a

A dorsal and ventral root of each spinal segment unite to form a spinal nerve.

Explanation:

Spinal nerves are the mixed nerves emerging from the spinal cord and exiting at the intervertebral foramen. A dorsal and ventral root of each spinal segment unite to form a spinal nerve.

Proximal branches of the spinal nerve includes:

Dorsal (posterior) root is sensory input to spinal cord Ventral (anterior) root is motor input of spinal cord.

Distal branches:

Dorsal ramus supplies the dorsal body, muscle and skin. Ventral ramus to ventral skin and muscles and limbs. Meningeal branch to meninges, vertebrae and ligaments.

This question lacks options, options are:

A. spinal meninx

B. cervical enlargement

C. spinal ganglion

D. spinal nerve

E. lumbar enlargement

The correct answer is D.

A dorsal and ventral root of each spinal segment unite to form a spinal nerve.

Explanation:

The spinal nerves (axon bundles) connect to each side of the spinal cord by a dorsal root and a ventral root. The afferent fibers enter through the dorsal root, while the efferent fibers exit through the ventral one. The cell bodies of the afferent neurons are concentrated in one dorsal root ganglion; those of efferent neurons, however, are found in the spinal cord itself, in the gray matter, and send axons through the dorsal root. Both roots unite in a single nerve when leaving the spinal cord, a nerve that, therefore, transmits information in both directions independently.