The occurence of a third head of the biceps brachii has been reported in several articles. The aim of this study is to determine on the incidence of the third head of biceps brachii in Turkish neonates and adults, and to compare it with other studies. Also the functional and phylogenetic importance of the third head was described here. The third head was studied in 160 arms of 60 (45 males, 15 females) neonatal and 20 (13 males, 7 females) adult cadavers and was found in 24 (15%) specimens. It had the three different origins and frequently arose from the anterior surface of the humérus and distal to the insertion of the coracobrachialis muscle. In all cases, the third head inserted into the conjoined tendon of biceps brachii and received its nerve supply from the musculocutaneous nerve. In our study the rate of the third head was different than those for most other published series and that the difference are possibly caused by evolutionary and/or racial trends in different studied populations. We believe that the third head of biceps brachii muscle is not a relatively rare variant. The knowledge of such variations may become significant in preoperative diagnosis and during surgery.

PubMed: 10429374