Cords of the Brachial Plexus and Their Branches Positioned Laterally to the Axillary Artery

The brachial plexus, which supplies the upper limb, extends from the interscalene triangle in the root of the neck to the axilla and is closely related to the subclavian and axillary arteries. Variations in the formation, branching pattern, and relations are profound, and it is generally stated that variant anatomy of the plexus appears to be a rule rather than an exception. In previous studies, it was hypothesized that the anomalous development of the subclavian-axillary stem and the persistence of intersegmental arteries could induce variations in the plexus. In this study, all three cords of the brachial plexus (lateral, medial, and posterior) and their terminal branches are consistently found lateral to the third part of the axillary artery. Most of the studies reported variation in one or the other cord or its branches, but very few studies have reported about all cords lateral to the brachial plexus. The brachial plexus variations are usually also associated with the variations in the branches of the axillary artery, but in this study, no such variation is noted in the branches of the axillary artery. These differences impact the methods of surgery and the application of regional anesthesia. For successful outcomes, it is important to know how neurovascular relationships work, such as where the cords are in relation to the axillary artery. We report an interesting case of all cords and their branches positioned lateral to the axillary artery in the axilla in an adult male cadaver.