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; an elongate plunger rod disposed within the barrel, the plunger rod comprising a distal portion and a proximal portion, and a stopper disposed on a distal end of the distal portion, the stopper having a distal face; and wherein the proximal portion is slidably mounted to the distal portion so that the plunger rod has an adjustable overall length which is extendible to a plurality of different locked lengths to permit varying amounts of fluid to be expelled from the barrel corresponding to the plurality of locked lengths; and wherein the distal portion slidably receives the proximal portion, the distal portion is hollow and the proximal portion is sized to be inserted into the distal portion; and wherein 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; and characterized in that the distal portion and proximal portion can be rotated with respect to each other, wherein in a first rotation position, the distal portion and proximal portion can be moved axially with respect to each other, and in a second rotation position, the distal portion and proximal portion can be locked to prevent relative axial movement of the distal portion and proximal portion. 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; an elongate plunger rod disposed within the barrel, the plunger rod comprising a distal portion and a proximal portion, and a stopper disposed on a distal end of the distal portion, the stopper having a distal face; and wherein the proximal portion is slidably mounted to the distal portion so that the plunger rod has an adjustable overall length which is extendible to a plurality of different locked lengths to permit varying amounts of fluid to be expelled from the barrel corresponding to the plurality of locked lengths; and wherein the distal portion slidably receives the proximal portion, the distal portion is hollow and the proximal portion is sized to be inserted into the distal portion; and wherein 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; and characterized in that the distal portion and proximal portion can be rotated with respect to each other, wherein in a first rotation position, the distal portion and proximal portion can be moved axially with respect to each other, and in a second rotation position, the distal portion and proximal portion can be locked to prevent relative axial movement of the distal portion and proximal portion.