Morphology of peripheral distribution of cutaneous nerves with special reference to relation to dermatome
Hirosaki Medical Journal 34(1): 1-13
Towards describing the exact distribution of all the cutaneous nerves of the arm, the forearm, and the middle portion of the back in man, all the nerves were dissected distally as far as they entered the undersurface of the corium. The cutaneous veins of the arm and forearm, especially the cephalic and basilic veins, were also dissected concurrently, in order to find the positional relations between the cutaneous nerves and the superficial veins. Upper extremities from 4 female infants, a mature female fetus and a back from a mature female fetus were examined. The border line of distribution of the ventral and dorsal divisions of cutaneous nerves in the upper extremity coincided with the course of the cephalic and basilic veins. Overlapped distribution of the adjacent cutaneous nerves in the arm and forearm was hardly found and each cutaneous nerve appeared to have its proper distributive area. The anterior axial line of the upper extremity described by Bolk (1898) and Kasai (1978) was located; it coincided with the course of the cephalic veins in the proximal portion of the arm. The superficial and deep anastomoses (described by Shinji, 1936) between the cutaneous nerves in the rami posteriores area of the spinal nerves of adjacent segments were sometimes found. Nerve supply in the central area of distribution of each segment was uni-segmental; that in the marginal area bi- or tri-segmental. The maximum spots of Head (1893), Heads zone (1900) and the central zone of Nozaki (1938) were discussed from the anatomical viewpoint. Over the mid-dorsal line of the back or the anterior axial line of the upper extremity, anastomosis or crossing between the branches of cutaneous nerves of both sides of the body or across the axial line was found in a few cases. It was thought to be anatomical evidence of crossed overlap or axial crossed overlap Sherrington 1894, Foerster, 1936 described in frog, monkey and man.