Anatomical Variations Of The Axillary Nerve: A Cadaveric Study

ABSTRACT

Background: Axillary nerve is one of the most common nerves which is prone to iatrogenic injuries (6% of all thebrachial plexus injuries). Knowledge of the anatomical variations of the axillary nerve in respect to its originfrom the posterior cord of brachial plexus, its site of division into anterior and posterior branch and its mode ofsupply to the deltoid muscle is highly important for anatomists, orthopedic surgeons, radiologists and anesthetistsfor proper exploration of the axillary region.Material and Methods: The study was carried out in the Department of Anatomy, Institute of PostgraduateMedical Education and Research, Kolkata, West Bengal. The sample size was 50 upper limbs of 25 formalinhardened human cadavers of both sexes.Results: Out of 50 samples, in 16% cases the Axillary nerve took origin as a common trunk. Regarding the site ofdivision of the axillary nerve into anterior and posterior branches it was found to be above the quadrangularspace in 12% cases and within the quadrangular space in 88% cases. . Regarding the mode of supply of thedeltoid muscle it was seen that the anterior part of the deltoid was supplied by the anterior division of theaxillary nerve in 100% cases; middle part of the deltoid solely by anterior division of the axillary nerve in 60%cases and in remaining 40% cases both from anterior and posterior branch i.e. dual supply (fig-3); the posteriorpart of the deltoid was seen to be supplied by the posterior branch in 100% cases.Conclusion: The knowledge of variations of axillary nerve is very important for anatomists, aneasthesists,orthopaedic surgeons and general physicians during surgical interventions of the axilla and intra-muscularinjections to the deltoid muscle.