An injection port assembly , comprising: a body having a first mating structure and a second mating structure configured to be coupled to the first mating structure ; a resilient barrier configured to be received within the body and compressible from a less compressed first position in which fluid flow through the injection port assembly is blocked to a more compressed second position in which fluid flow through the injection port assembly is permitted, the resilient barrier including an internal cavity ; and a hollow cannula coupled to the first mating structure and configured to be received within internal cavity of the resilient barrier , the hollow cannula having a longitudinal central axis , the hollow cannula including: a cannula distal end portion configured to extend through the resilient barrier when the resilient barrier is in the more compressed second position; at least one lateral outlet window formed in the cannula distal end portion the at least one lateral outlet window having a window width perpendicular to the longitudinal central axis ; and characterized in that , an internal fluid passageway defined in the hollow cannula and configured to communicate the at least one lateral outlet window with a fluid conduit connected to the first mating structure , the internal fluid passageway having a non-circular cross section taken in a plane perpendicular to the longitudinal axis, the non-circular cross section extending axially proximal from the window , the non-circular cross section having a cross section area greater than a cross section area of a circle of diameter equal to the window width . a body having a first mating structure and a second mating structure configured to be coupled to the first mating structure ; a resilient barrier configured to be received within the body and compressible from a less compressed first position in which fluid flow through the injection port assembly is blocked to a more compressed second position in which fluid flow through the injection port assembly is permitted, the resilient barrier including an internal cavity ; and a hollow cannula coupled to the first mating structure and configured to be received within internal cavity of the resilient barrier , the hollow cannula having a longitudinal central axis , the hollow cannula including: a cannula distal end portion configured to extend through the resilient barrier when the resilient barrier is in the more compressed second position; at least one lateral outlet window formed in the cannula distal end portion the at least one lateral outlet window having a window width perpendicular to the longitudinal central axis ; and a cannula distal end portion configured to extend through the resilient barrier when the resilient barrier is in the more compressed second position; at least one lateral outlet window formed in the cannula distal end portion the at least one lateral outlet window having a window width perpendicular to the longitudinal central axis ; and characterized in that , an internal fluid passageway defined in the hollow cannula and configured to communicate the at least one lateral outlet window with a fluid conduit connected to the first mating structure , the internal fluid passageway having a non-circular cross section taken in a plane perpendicular to the longitudinal axis, the non-circular cross section extending axially proximal from the window , the non-circular cross section having a cross section area greater than a cross section area of a circle of diameter equal to the window width . <EOS>