[Anatomical variations of the brachial plexus].

Important variations exist in the brachial plexus (Kaufmann, Cunningham, Kerr, Lee). Perivascular techniques of brachial plexus block used sometimes use important quantities of anaesthesia product. It seems that certain surgical treatment failures of brachial plexus lesions are related to the brachial plexus variations (Bonnel). Our aim is to study the brachial plexus variations and its relations from the cervical region to brachial region. We dissected twenty-three brachial plexus (13 women and 10 men, fresh or injected by formalin). We studied the brachial plexus anatomic variations and its relations. We found the anatomic variations at the level of different parts of brachial plexus: Trunk: 8 cases (34.8%); Terminal branch: 8 cases (34.8%); brachial plexus tract: 1 case (4.3%); collateral branch: 1 case (4.3%); in 5 cases we didn't find any abnormalities. Some studies show the frequency of 4th cervical root (C4) participation in brachial plexus. Kerr found 65.9%. It was 30.4% of C4 participation in brachial plexus in our series. Among the 8 cases of terminal branch variations in our series, two (8.7%) musculocutaneous was low source. The brachial plexus variations could fail the brachial plexus loco-regional anaesthesia. In the surgical treatment of brachial plexus lesions, the surgeon must know brachial plexus anatomical variations perfectly.