Cerebral crus
Crus cerebri
Definition
The cerebral crus spreads over the ventral surface of the cerebral peduncle, the most ventral structure of the midbrain. It is composed entirely of white matter and corresponds to a large bundle of cortical axons. These fibers originate from neurons of the cerebral cortex.
The two crura cerebri border the interpeduncular fossa on the ventral surface of the midbrain. Within this fossa lies the caudal perforated substance, a region through which numerous blood vessels enter. Each cerebral crus also presents a medial sulcus that separates it from the midline. Finally, the transverse crural tract crosses the surface of the crus cerebri in a medial direction and connects the brachium of the rostral colliculus to mesencephalic nuclei.
The crus cerebri contains the main descending motor tracts originating from the cerebral cortex (corticospinal, corticopontine, corticonuclear, corticoreticular), which convey information from the cortex to the brainstem and spinal cord.
It is much less developed in domestic mammals than in humans.
References
Barone R, Bortolami R. Anatomie comparée des mammifères domestiques, Tome 6, Neurologie I, Vigot, Paris, 2004.
Evans HE, de Lahunta A. Miller’s anatomy of the dog, 4th edition, Elsevier Saunders, St Louis, 2012.
