Axial section of the medulla at the level of the olive before the central canal has opened into the fourth ventricle

An area of infarction is evident in the left lateral medulla. The area of infarction extends further medially. Destroyed here are, in addition to the long (spinotectal and spinothalamic) tracts of the lateral medulla, the most lateral internal arcuate fibers (fibrae arcuatae internae), the cerebello-olivary fibers (fibrae cerebello-olivares), the dorsal and ventral spino-cerebellar tracts (fibrae spino-cerebellares dorsales et ventrales), the ventral two-thirds of the spinal trigeminal nucleus, lateral parts of the nucleus ambiguous near its caudal end and the nucleus lateralis medullae (nucleus reticularis lateralis), and finally the most caudal vagus fibers as they pass through the spinal trigeminal nucleus. The narrow, unmyelinated layer extending dorsally along the restiform body (corpus restiforme; inferior cerebellar peduncle) can be partly described as secondary degeneration. (Source: Wallenberg A. Anatomischer Befund in einem als “acute Bulbär-aVection [Embolie der Art. cerebellar. post. inf. sinistr?]” bescreidenen Falle. Archiv für Psychiatrie und Nervenkrankheiten 1901;34:923-59. Edited by Dr. Douglas J Lanska.)