The invention relates to a surgical instrument system, which comprises a hollow shaft as well as a shaft-type instrument that can be inserted into the hollow shaft. To create a surgical instrument system that consists of a hollow shaft and of a medical instrument that can be inserted into the hollow shaft and that is both simple in construction and capable of a range of uses, it is proposed according to the invention that at least one cam that reduces the inside diameter of the hollow shaft should be positioned on the interior of the hollow shaft.
