The cerbral peduncles are structures at the front of the midbrain which arise from the front of the pons and contain the large ascending (sensory) and descending (motor) nerve tracts that run to and from the cerebrum from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are the cortex, the spinal cord and the cerebellum. The
cerebral peduncle, by most classifications, is everything in the
mesencephalon except the
tectum. The region includes the
midbrain tegmentum,
crus cerebri and
pretectum. By this definition, the cerebral peduncles are also known as the
basis pedunculi, while the large ventral bundle of efferent fibers is referred to as the
crus cerebri or the
pes pedunculi.