Anatomical study of the brachial plexus in human fetuses and its relation with neonatal upper limb paralysis

Objective To study the anatomy of the brachial plexus in fetuses and to evaluate differences in morphology during evolution, or to find anatomical situations that can be identified as the cause of obstetric paralysis. Methods Nine fetuses (12 to 30 weeks of gestation) stored in formalin were used. The supraclavicular and infraclavicular parts of the brachial plexus were dissected. Results In its early course, the brachial plexus had a cord-like shape when it passed through the scalene hiatus. Origin of the phrenic nerve in the brachial plexus was observed in only one fetus. In the deep infraclavicular and retropectoralis minor spaces, the nerve fibers of the brachial plexus were distributed in the axilla and medial bicipital groove, where they formed the nerve endings. Conclusion The brachial plexus of human fetuses presents variations and relations with anatomical structures that must be considered during clinical and surgical procedures for neonatal paralysis of the upper limbs.