Abstract: A system for injecting includes a syringe body, a syringe interior, a syringe flange, and a stopper member and an injectable fluid disposed in the syringe interior. The system also includes a plunger member coupled to the stopper member. The system further includes a finger flange removably coupled to the syringe flange, the finger flange defining a pair of side openings and a pair of bumps adjacent respective side openings. Moreover, the system also includes a swing spacer rotatably coupled to the finger flange, the swing spacer defining a pair of arms, a pair of pivot pins, two pairs of slots, and a pair of indentations. The swing spacer is configured to define a distance of movement of the plunger member relative to the syringe body along a longitudinal axis of the syringe body, thereby defining a dose of the injectable fluid.

Abstract: A system for injecting includes a syringe body, a syringe interior, a syringe flange, and a stopper member and an injectable fluid disposed in the syringe interior. The system also includes a plunger member coupled to the stopper member. The system further includes a finger flange removably coupled to the syringe flange, the finger flange defining a pair of side openings and a pair of bumps adjacent respective side openings. Moreover, the system also includes a swing spacer rotatably coupled to the finger flange, the swing spacer defining a pair of arms, a pair of pivot pins, two pairs of slots, and a pair of indentations. The swing spacer is configured to define a distance of movement of the plunger member relative to the syringe body along a longitudinal axis of the syringe body, thereby defining a dose of the injectable fluid.

Abstract: A system for serially injecting liquids includes a syringe body, proximal and distal stopper members disposed in the syringe body, a first liquid in a distal chamber, a second liquid in a proximal chamber, a plunger member, and a needle hub assembly coupled to a distal needle interface of the syringe body. The plunger member includes a needle retention feature disposed in a plunger interior, an energy-storage member disposed in the plunger interior, and an energy-storage member latching member disposed in the plunger interior. The needle assembly includes a needle having a needle proximal end feature, a hub, and a needle latching member configured to couple the needle to the hub. Manipulating the plunger member to insert the proximal stopper member distally relative to the syringe body initially expels the first liquid, then the second liquid. The needle is at least partially retractable into plunger interior.