biomedicalephemera:

Dermatomes of the Adult Male

A dermatome is an area of the body supplied by a single spinal nerve ganglion. Physical sensations (and as such, autonomic/spinal reactions) are controlled by these nerves.



Technically “dermatome” only refers to the skin supplied by that nerve (derma - “skin”, -tome “single section”), but as the lower graphics show, we’ve also determined what nerves control the sensations of our muscles.

As you can see in the graphic of the trigeminal nerve innervation at the top, there’s a moderate amount of variation between individuals, but the basic layout is generally the same.



Because the basic layout of our nerves is known, when someone damages a nerve, which nerve has been damaged can sometimes be determined by what area of the skin has abnormal sensations. A few years ago, I damaged my elbow at work, and it was determined that my ulnar nerve had been affected, due to the lower third of my arm and hand being numb. Thankfully it’s since recovered, but in some situations, nerve damage can cause permanent altering of sensation in the parts of the body affected.



Atlas of Applied (Topographical) Human Anatomy for Students and Practitioners. J. Howell Evans, 1906.

