Along the dorsal root is a collection of cell bodies called the dorsal root ganglion . Inside the ganglion are the cell bodies of all the receptor neurons that send processes out to the periphery. The free nerve ending in the tip of your finger that feels the paper cut actually has its cell body back in the dorsal root ganglion. As you can see from the picture, the dorsal root ganglion is actually located ventrally, but you can tell that it is part of the dorsal root. In general, you should be able to differentiate cervical from thoracic from lumbar from sacral.
Cervical sections tend to be wide and squashed looking, like an oval.
Compare the cervical section to the round lumbar section. The second thing to check for is a ventral horn enlargement . At segments that control a limb, the motor neurons are large and numerous. If you see an enlargement, you just need to differentiate cervical from lumbar. The amount of white matter relative to grey matter decreases as you move down the cord.