Morphological Investigation of the Peripheral Distribution of Cutaneous Nerves in the Upper Extremity

Abstract

The precise distribution of the cutaneous nerves in the upper extremity and the positional relations with respect to the superficial veins were examined in two adults and three mature fetuses. In the fetuses, a skin flap stripped from the underlying deep fascia was placed upside down in water to trace the cutaneous nerves under a stereoscopic microscope. By this method, all the cutaneous nerves could be followed peripheralwards as they entered the undersurface of the corium, preserving the entire course of the nerves without interruption. The results obtained were as follows.
1) Accoding to previous work by the authors, not only the muscular nerves of the brachial plexus but also the cutaneous ones could be classified into ventral and dorsal derivatives. The boundaries of distribution between the ventral and dorsal cutaneous nerves coincided with the course of the cephalic and basilic veins.
2) Overlapping of distribution between adjacent cataneous nerves could not be observed. Thus against Foerster's findings in the living body which demonstrated a broad overlap of distribution between cutaneous nerves, each cutaneous nerve had its own supply area, and no other nerves supplied the same region.
3) The course of the anterior axial line which had been observed physiologically as boundaries between discontinuous dermatomes, could be determined anatomically. In the proximal half of the arm, it coincided with the course of the cephalic vein.