The spinal ganglion, located in the dorsal root of the spinal nerve, contains the cell bodies of sensory neurons. These neurons transmit sensory information from the periphery (like touch, pain, or temperature) to the central nervous system (CNS). The ganglion is situated just outside the spinal cord, near the point where the dorsal root enters the spinal cord. It plays a key role in relaying sensory input to the brain.