An endoscope or other medical device includes a number of lumens positioned in an outer shaft. The lumens are formed as a multiple lumen assembly. In one embodiment, individual lumens are connected to each other with a sheet or webbing material. The lumen assembly is rolled or folded along its length for incorporation into the outer shaft of the medical device. The sheet or webbing material may be notched or perforated to facilitate folding the lumen assembly and/or separating individual lumens from the lumen assembly.