The<unk> , by most classifications, is everything in the mesencephalon except the tectum. The region includes the midbrain tegmentum, crus cerebri, substantia nigra and pretectum. The<unk> s are also known as the crus cerebri. There are numerous nerve tracts located within this section of the brainstem. Of note, in the<unk>  peduncular loop fibers from motor areas of the brain project to the<unk>  and then project to various thalamic nuclei.
Inasmuch as the<unk> s are an anatomic landmark, for details regarding the function of this area interested readers are referred to the individual referenced articles. On a broad scale, though, this area contains many nerve tracts conveying motor information to and from the brain to the rest of the body.
Cerebral peduncle
Lingula of cerebellum
Vallecula of cerebellum
Uvula of cerebellum
Inferior cerebellar peduncle
Anterior commissure
Periaqueductal gray
Cerebellar vermis