Topographical relationships of intramuscular nerves and vessels of the motor endplates in the thigh and gluteal regions of human fetuses: an immunohistochemical study

The aim of this study was to describe topography of vessels and nerves in striated muscles to understand individual muscle function. Immunohistochemistry for nerve and artery was used to examine the thigh and gluteal muscles of six human midterm fetuses. The supplying nerves often accompanied arteries along epimysium bundling muscle fibers as well as in the covering fascia surrounding the entire muscle mass. However, courses of nerve twigs were usually independent of those of vessels in muscle bundles. Notably, irrespective of whether or not the vascular bundle accompanied the nerves at the muscle surface or hilus, most of the motor endplate bands did not accompany the vessels. Since the motor endplates were low vascularised, a chemical induction of vessels for nerve terminal development (or the reversed induction) seemed unlikely in striated muscles. In contrast to proprioceptive neuromuscular facilitation, manual stimulation of the endplate bands may stimulate muscle activity without sympathetic reflexes through vessel-accompanying nerves.