A flexible filament controlled locking medical catheter having a flexible tube with at least one drainage or feeding hole, a restraining portion at its distal end and a housing at its proximal end, and a filament having a proximal control portion for controlling the restraining portion of the tube. The flexible filament passes through an open port in the sidewall of the housing and an elastomeric cover as well as through the interface between the cover and a seal sleeve over the cover. A locking mechanism to lock the filament in position is provided and may comprise corresponding teeth with means for moving the teeth into tight engagement to clamp the flexible filament therebetween.
