A syringe comprising: a) a substantially cylindrical syringe barrel comprising a fluid dispensing end and an open end ; b) a stopper configured to be received within the open end of the syringe barrel, the stopper comprising: i) a main body portion defining an open rearward end configured to receive a plunger rod , an engagement portion provided along an inner circumference of the main body portion , and a closed front end forming a flexible roof, wherein the flexible roof is flat or the closed front end of the main body portion includes a first angled portion and a second angled portion forming a single conical surface that extends toward a tip providing the closed front end ; and ii) a first perimetrical skirt extending around an outer circumference of the main body portion toward the closed front end of the main body portion ; and c) a plunger rod having a plunger rod body extending along a longitudinal axis, the plunger rod body comprising a front attachment end having a radially extending member configured to engage the engagement portion provided along the inner circumference of the main body portion of the stopper and a back end, wherein, when fluid pressure is increased inside the syringe barrel during an injection, the flexible roof expands in a radial direction toward an inner wall of the syringe barrel , the first perimetrical skirt is forced against the inner wall of the syringe barrel , and an engagement between the plunger rod and the engagement portion forces the main body portion to expand in the radial direction toward the inner wall of the syringe barrel , wherein the front attachment end of the syringe plunger body comprises an extension portion distinct from the radially extending member and extending in a longitudinal direction with respect to the longitudinal axis of the plunger rod and toward the closed front end of the stopper, said extension portion configured to contact a lower surface of the flexible roof during an injection to limit the expansion of the flexible roof in the radial direction. a) a substantially cylindrical syringe barrel comprising a fluid dispensing end and an open end ; b) a stopper configured to be received within the open end of the syringe barrel, the stopper comprising: i) a main body portion defining an open rearward end configured to receive a plunger rod , an engagement portion provided along an inner circumference of the main body portion , and a closed front end forming a flexible roof, wherein the flexible roof is flat or the closed front end of the main body portion includes a first angled portion and a second angled portion forming a single conical surface that extends toward a tip providing the closed front end ; and ii) a first perimetrical skirt extending around an outer circumference of the main body portion toward the closed front end of the main body portion ; and i) a main body portion defining an open rearward end configured to receive a plunger rod , an engagement portion provided along an inner circumference of the main body portion , and a closed front end forming a flexible roof, wherein the flexible roof is flat or the closed front end of the main body portion includes a first angled portion and a second angled portion forming a single conical surface that extends toward a tip providing the closed front end ; and ii) a first perimetrical skirt extending around an outer circumference of the main body portion toward the closed front end of the main body portion ; and c) a plunger rod having a plunger rod body extending along a longitudinal axis, the plunger rod body comprising a front attachment end having a radially extending member configured to engage the engagement portion provided along the inner circumference of the main body portion of the stopper and a back end, <EOS>