Localization of the pyramidal tract in the internal capsule by whole brain dissection.

Six human brains were dissected by blunt technique and sectioned horizontally to establish the three-dimensional relationships of the pyramidal tract and the internal capsule. In all instances, the pyramidal tract entered the rostral capsule in the anterior half of the posterior limb and progressively shifted into the posterior half of the posterior limb in the more caudal horizontal sections. These observations resolve the current controversy about the exact anatomic location of the pyramidal tract in the posterior limb of the internal capsule. This controversy arose because previous authors failed to consider the changing rostrocaudal/anterior-posterior anatomy of the pyramidal tract as it courses through the posterior limb.