The invention relates to a prosthesis shaft system with a rigid outer shaft (10) which has a proximal outer shaft opening (14) for receiving an extremity stump of a wearer of the prosthesis shaft system, and a flexible inner shaft (20), which is connected to the outer shaft (10), and has a proximal inner shaft opening (24) for receiving the extremity stump, wherein at least one sealing lip (26) is arranged on an inner side of the inner shaft (20) facing the extremity stump.
