A medical device comprises an elongated, flexible band equipped with ratchet members and connected to a device head having a channel dimensioned for reception of the band. A lock member is connected to the head and configured to interlock the ratchet members when the band is pulled through the channel to form a reverse-motion brake. A protrusion and a matching protrusion receiving member are arranged in the head in connection with the channel entrance and in the band in connection with the band-head interface. The protrusion receiving member is dimensioned for reception of the protrusion when the band is close to fully pushed into the head.