Sheath assembly for the insertion of a cord-shaped element (32, 105), comprising an introducer sheath (101), the distal end (102) and the proximal end (103) of which protrudes from the body of the patient during insertion of the distal end into the body of the patient, and comprising an auxiliary sheath (104) for insertion into the introducer sheath (101) together with the cord-shaped element (32, 105), with first fastening means (106) for detachably fastening the auxiliary sheath to the introducer sheath, and with second fastening means (107) for detachably fastening the cord-shaped element to the auxiliary sheath, wherein the introducer sheath (101) has a first sheath housing (13, 114) and therein, a first sheath inner chamber (110) having a first receiving channel for a cord-shaped element (32, 105), and a first flushing device (108) for flushing the sheath inner chamber (110).
