gms | German Medical Science

Objectives/Interrogation: Demonstrate the positioning of the divisions and cords of the brachial plexus of the adult and the child.

Methods: The work consists of 10 brachial plexus of adult men dissected by the same team. The findings were compared with the literature through a review including articles of interest in the area.

Results and Conclusions: We find the same anatomy in the 10 dissected plexuses. Contrary to what most diagrams represent, we observe that all posterior divisions have superior and posterior positioning, whereas anterior divisions have inferior and anterior positioning. Reviewing articles published in the literature, we have identified conflicting results. In the articles involving dissection of adult, the results were similar to ours, we identified reports of 254 dissected brachial plexuses and all had the same anatomical position described previously. We observed different positioning when the articles used infantile brachial plexuses. 340 dissections were analyzed and all were different from the adult brachial plexus. In the infantile plexus, the posterior divisions of the upper and middle trunk had inferior and posterior positioning, while the posterior division of the inferior trunk had superior and posterior positioning. The anterior divisions of the upper and middle trunk had superior and anterior positioning, whereas the anterior division of the lower trunk had inferior and anterior positioning. The lateral cord was formed by the anterior divisions of the upper and middle trunk as well as in the adult, but it was the most cranial cord among all, while in the adult it was central. The posterior cord was formed by the fusion of all posterior divisions not differing from the adult, but it was situated in a central position, while in adult was the most superior of all. The medial cord is similar between the infantile and adult plexus, being formed by the continuation of the anterior division of the inferior trunk and still considered the lower cord of all.

The differences between the anatomy of the brachial plexus for children and adults are evident. We know that the nerve roots in the child are more horizontal and that at the end of growth they end up positioning obliquely and posteriorly, however, it is clear that the modifications are not restricted only to the roots, but also to the positioning of the divisions and cords. Unifying the graphical representation of the brachial plexus of adults and children is a serious error because it does not represent reality.