Summary of known anastomoses between the long branches of the brachial plexus and their clinical significance.

The brachial plexus consists of nerves that supply the upper limb and some nerves of the back, torso, and neck. It is formed by the ventral rami of C5 to T1 (in some cases, C4 or T2 also contribute). The anterior rami of the spinal nerves unite to the roots, trunks, divisions, cords, and terminal branches that innervate muscles and skin. An example is its association with the terminal branches of the long nerves. Knowledge of this variation is necessary for enabling surgeons, orthopaedists, and neurologists to avoid injury during surgical exploration in the arm or axilla region, and for achieving correct diagnoses, because such variability can evoke nonspecific responses. Awareness of this anastomosis is also mandatory for anaesthetists performing anaesthesia in the upper limb region. The aim of this article is to describe anastomoses between long nerves from the brachial plexus and to consider their clinical significance.