Can you tell me the function of the dorsal root of the spinal nerve?

Lets you feel things. The nerve root has 2 "ganglions". The dorsal root is on the posterior side of the nerve (closer to your back) and carries the fibers that allow you to feel things in your extremities (for example: pain, temperature, vibration). The information is transmitted to your brain so you understand what type of sensation is being encountered by the extremity.
It is the region . Where the neurons are located for the spinal nerves that send signals to the brain and the ganglion is very sensitive to pressure and ph changes or acidity.