A syringe assembly including a plunger rod having a first end, a second end, and a rod portion extending therebetween, wherein at least a portion of the rod portion is flexible is disclosed. The flexible portion of the rod portion allows a stopper to be moved between a first position and a second position within a syringe barrel while the overall length of the syringe assembly remains the same throughout the movement between the first position and the second position. In another embodiment, a syringe assembly including a restraining member adapted to communicate with the flexible portion of the rod portion such that movement of the first end of the plunger rod in a first direction actuates movement of the second end of the plunger rod in a second direction different than the first direction is disclosed.