Abstract: Apparatus and methods of utilizing the same to prevent accidental medical needle sticks are disclosed, characterized by use of a raised locking member coaxially mounted upon the needle approximately midway between a body member mounting the needle and the needle tip which presents an exterior contour to engage complementary features within the interior channel of a tubular sleeve which slides coaxially along the needle. The slidable sleeve is held at a first position proximate the body member and exposing the needle tip by a mechanical detent formed from frictional engagement of complementary surfaces upon the sleeve and the locking member and/or the body member. After medical use, the spent and contaminated needle is sheathed by sliding the tubular sleeve to a second position wherein it is securely held by a detent resultant from engagement with the locking member. The sheathing guards against accidental needle sticks transmitting disease.