Patent ID: 8197443

Claim:
A syringe comprising: a housing having a proximal end and a distal end configured for attachment to a needle and defining a cavity; a plunger partially contained within the housing and partially external to the housing, the plunger comprising a distal gasket seal that provides a fluid-tight seal with the housing, the cavity and the plunger defining a fluid chamber; and a biasing element contained entirely within the housing, wherein the fluid chamber is distal to the biasing element, and wherein the plunger is configured to be proximally withdrawn, thereby resulting in proximal withdrawal of the distal gasket seal, and wherein when a needle is attached to the distal end of the housing and is advanced into a body of a subject while the plunger is proximally withdrawn, the plunger will move from its proximally withdrawn position toward the distal end of the housing when the needle experiences a loss of resistance, as a result of a force exerted on the plunger by the biasing element.