Final answer:
Sensory and motor fibers enter and leave the spinal cord as dorsal and ventral roots, respectively. These roots merge to form spinal nerves that exit through the intervertebral foramina. Dorsal root axons are sensory, associated with the dorsal root ganglion, while ventral root axons are motor.
Step-by-step explanation:
Sensory and motor fibers enter and leave the cord respectively as rootlets that then coalesce peripherally into dorsal and ventral roots, which merge to form spinal nerves, which exits the spinal canal at the intervertebral foramina.
The dorsal (posterior) nerve root axons enter the spinal cord through the posterolateral sulcus and are associated with the dorsal (posterior) root ganglion, which is a sensory ganglion. On the other hand, the ventral (anterior) nerve root axons emerge from the anterior or lateral horns of the spinal cord, containing motor fibers. These roots come together to form the spinal nerve, which is a mixed sensory and motor nerve exiting the vertebral column through the intervertebral foramina, enabling peripheral nervous system communication.