The invention relates to a puncture system having an outer tubular body which is designed to remain in a body part of a living being, said puncture system comprising at least one inner tubular body and a puncture needle, wherein the inner tubular body is guided through a working lumen of the outer tubular body and is longitudinally displaceable relative to the outer tubular body, and the puncture needle is guided through a puncture lumen of the inner tubular body and the inner tubular body is longitudinally displaceable relative to the puncture needle. The puncture system has a manually actuatable element that can be moved by manual actuation at least into a fixing position and into a release position, wherein, in the fixing position, the longitudinal displaceability a1) of the inner tubular body relative to the outer tubular body and/or a2) of the puncture needle relative to the inner tubular body and/or a3) of the puncture needle relative to the outer tubular body is removed or reduced.