Patent ID: 7976510

Claim:
A medical device comprising: a syringe barrel having a side wall with an inside surface defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall having a passageway therethrough in fluid communication with the chamber, the open proximal end including a peripheral flange; and an elongate plunger rod disposed within the barrel, the plunger rod comprising a distal portion, a proximal portion, and a stopper disposed on a distal end of the distal portion, the stopper having a distal face and a proximal end, the proximal portion of the plunger rod slidably mounted to the distal portion so that the overall length of the plunger rod is reversibly adjustable to a plurality of different locked lengths between a compressed locked length and a fully extended length, thereby permitting varying amounts of fluid to be expelled from the barrel corresponding to the plurality of locked lengths, wherein one of the distal portion or proximal portion slidably receives the other of the distal portion or proximal portion, wherein the one or the other of the distal portion or proximal portion is hollow and the other of the distal portion or proximal portion is sized to be inserted into the hollow portion, and wherein the distal portion is hollow and the proximal portion includes a plurality of depressions spaced axially along the proximal portion that cooperate with a tab disposed on the distal portion to provide a plurality of locked positions and to provide a plunger rod that can have a plurality of locked lengths.