the great majority of which tracts pass through the corpus callosum
Commissural fiber The commissural fibers make up tracts that include the corpus callosum, the anterior commissure, and the posterior commissure.
Corpus cavernosum penis A corpus cavernosum penis (singular) (cavernous body of the penis) is one of a pair of sponge-like regions of erectile tissue, the corpora cavernosa (plural) (cavernous bodies), which contain most of the blood in the penis during an erection. Such a corpus is homologous to the corpus cavernosum clitoridis in the female; the body of the clitoris contains erectile tissue in a pair of corpora cavernosa (literally "cave-like bodies") with a recognisably similar structure.