A catheter assembly is provided having a balloon disposed at the distal end thereof. The balloon is capable of being inflated to selectively dilate from a collapsed configuration to an expanded configuration. A syringe assembly is in fluid communication with a delivery lumen of the catheter assembly for allowing a therapeutic substance to be injected into a tissue of a passageway. The syringe assembly includes a portion capable of pivoting from a first position towards a second position when the balloon is being inflated from the collapsed configuration to the expanded configuration. The portion of the syringe assembly is also capable of pivoting from the second position back towards the first position when the balloon is being deflated.