The inner segment is the part of the collecting duct system between the outer segment and the papillary ducts.

The terminal portions of the medullary collecting ducts are the "papillary ducts", which end at the renal papilla and empty into a minor calyx.

The inner segment is the part of the collecting duct system between the outer segment and the papillary ducts.

The terminal portions of the medullary collecting ducts are the "papillary ducts", which end at the renal papilla and empty into a minor calyx.