Sheath assembly for insertion of a cord-shaped element, particularly a catheter, into the body of a patient

A sheath assembly for insertion of a catheter into the body of a patient, said assembly comprising:

• an introducer sheath having a proximal end and a distal end, the distal end of the introducer sheath configured to be inserted into the body of a patient while the proximal end protrudes from the body of the patient;
• an introducer sheath housing coupled to the proximal end of the introducer sheath;
• an auxiliary sheath having a proximal end and a distal end, the distal end of the auxiliary sheath configured to be inserted into the introducer sheath housing;
• an auxiliary sheath housing coupled to the proximal end of the auxiliary sheath, comprising:
• first fastening means sized and positioned to detachably fasten the auxiliary sheath housing with respect to the introducer sheath housing when the distal end of the auxiliary sheath is proximal of a proximal end of the introducer sheath, and
• second fastening means sized and positioned to detachably fasten the catheter with respect to the auxiliary sheath.