Abstract: A mechanical latching device is provided for threaded connections, such as a barrel and hub member of a medical syringe. The latching device includes an abutment and a receptacle for receipt of the abutment whereby relative movements between reciprocal members in one direction is initially terminated and subsequent movements in another direction are resisted. Movement termination in one direction and resistance in another direction may be overcome in one, or both, of the members forming the threaded connection are radially distortable to permit the members to overcome movements interference by the abutment/receptacle relationship.