The 2-Dimensional and 3-Dimensional Anatomy of the Adult Brachial Plexus Divisions and Cords.

Background: The objective of this work was to perform a critical review of the 2-dimensional and 3-dimensional anatomy of the adult brachial plexus divisions and cords. Methods: Twelve adult brachial plexuses from fresh cadavers were dissected. All were male and aged between 30 and 50 years. Only corpses without brachial plexus injuries were selected. The purpose of the dissections was to identify the origin of the anterior and posterior divisions of the adult brachial plexus in their respective trunks, as well as the positioning of the posterior, lateral, and medial cords. Results: The posterior division of all trunks had a cranial and dorsal origin, while the anterior division of all trunks had a caudal and ventral origin. The posterior cord was the most cranial of all, the lateral cord was central, and the medial cord was the most caudal of all cords. The posterior division of the superior trunk was always between the suprascapular nerve and the anterior division. Conclusions: Brachial plexus diagrams in most textbooks and papers are different from what was found in our dissections. Contrary to the known diagram, the posterior divisions always had a cranial origin in the superior, middle, and inferior trunks.