According to the painstaking researches of Prof. Otfrid Foerster, of the University of Breslau, Germany, the innervation of the skin by the spinal nerves is not accurately set forth in standard textbooks of neurology. This investigator has had as one of his projects for many years the study of the segmental innervation of the skin. Since the expanded results of his work1 are not readily available, permission has been granted me to summarize and republish them.
There are several methods of determining the distribution in the skin of the spinal nerves:
Dissection. An individual root may be followed by anatomic dissection from a ganglion, through a plexus if necessary, to the ends of the fine branches in the skin.
Isolation. Roots above and below that at the level to be investigated may be divided, only the cutaneous representation of the selected root being left to be determined by test.
FENDER FA. FOERSTER'S SCHEME OF THE DERMATOMES. Arch NeurPsych. 1939;41(4):688-693. doi:10.1001/archneurpsyc.1939.02270160044003