G, The tela choroidea, in which the choroid plexus arises, has been folded downward to expose the lower part of the floor. H, Enlarged view of the left lateral recess and the foramen of Luschka. The rhomboid lip is a thin layer of neural tissue, which extends laterally from the anterior margin of the lateral recess and, with the tela choroidea, forms a pouch at the outer edge of the lateral recess. Choroid plexus extends through the lateral recess and foramen of Luschka into the cerebellopontine angle. I, The tela has been removed to expose the parts of the floor located above and below the nodule and inferior medullary velum. J, The nodule and the inferior medullary velum have been removed to expose the full length of the floor, which is divided in the midline by the median sulcus and craniocaudally into pontine, junctional, and medullary parts. The superior and inferior peduncles face the ventricular surface. The middle cerebellar peduncle is separated from the ventricular surface by the superior and inferior peduncles. (Courtesy of AL Rhoton.)