[Morphologic and biometric data on the constitution of the brachial plexus in man]

The authors relate the results of the examination of 172 human brachial plexuses from 89 leukoderma subjects native from the Parisian area. The origin of the plexus, with a participation of the fourth cervical nerve root in 41 p.c. of the plexuses, and its distribution, with three primary trunks in 90 p.c. of the plexuses were correctly described by classic authors. The secondary ventro medial trunk receives fibers from the middle primary trunk in 10 p.c. of the plexuses. The biometric study shows that the seventh cervical root is the largest on both sides and that secondary trunks are longer than the primary.