Fetal topography of cubital region nerves

Abstract

Background. The expansion of indications for surgical interventions on the structures of the elbow area is due to the need for a purposeful study of individual and age-related features of the innervation of the skin of the elbow region and the capsule of the elbow joint. Objective is to find out the sources of innervation of the skin of the elbow region and the articular capsule of the elbow joint in human fetuses of 4-10 months. Methods. A macromicroscopic study was carried out on preparations of the upper limbs of 26 human fetuses of 81.0-375.0 mm parietalcoccygeal length (PCL). Results. In some of the examined fetuses, a classical version of the topography of the nerves of the ulnar region was observed. General innervation of the elbow joint is possible by the articular branches of the median, ulnar and variable nerves. An atypical version of the topography of the left medial cutaneous nerve of forearm was observed in a fetus of 225.0 mm PCL, which branched into three branches: lateral, intermediate, and median. In one case (fetus 260.0 mm PCL), a connection between the right musculocutaneous nerve and the right medial cutaneous nerve of arm was detected. The left medial cutaneous nerve of arm was absent in a fetus of 170.0 mm PCL, in this case, the left median cutaneous nerve of the forearm provided sensitive innervation of the skin of the anteromedial surface of the shoulder, which may indicate compensatory development of its branches. Conclusions. Variability of the amount and sources of origin of the branches providing innervation of the capsule of the elbow joint and the skin of the elbow region has been established in human fetuses. We believe that the zone of impaired sensitivity in the case of damage to the cutaneous nerves of the shoulder and elbow areas, and areas of the forearm, as a rule, are smaller than the anatomical areas of distribution of the cutaneous nerves or their branches. It is because some areas of the skin of the elbow area support additional innervation from adjacent nerves – “overlap zones”. The described variants of individual and age-related anatomical variability of the nerves of the ulnar region in human fetuses contribute to the improvement of surgical tactics for performing reconstructive operations in case of traumatic damage to the long branches of the brachial plexus.