Study of the Anatomical Variations of the Median Nerve in Human Fetuses

Introduction: The median nerve is one of the most important terminal branches of the brachial plexus. Anatomical variations in the formation of the median nerve are common and have been reported by several authors.
Objective: The aim of this study was to analyze the anatomical variations of the median nerve in cadavers of human fetuses, from its origin to the formation of the median nerve.
Materials and Methods: Twenty-five fixed human fetuses (50 upper limbs) were dissected by planes with conventional technique and classic instrumentation.
Results: The frequency of variation in formation of the median nerve was 28%. The more frequent anatomical variations were: a communicant branch between the median and the musculocutaneous nerves (10%) and a lateral cord which gave rise to a couple of lateral branches to formation of the median nerve (8%).
Conclusions: Anatomical variations of the median nerve and its roots described in this study confirm the frequent occurrence of these variations in the brachial plexus neuroanatomy. An unusual variation during the formation of median nerve was also described. The significance of such variations are relevant to surgeons, anesthetists and clinicians in the management of surgical exploration of the axilla, in the clinical investigations and in the nerve blocks procedures of the brachial plexus.