When a syringe or other device is used to create an increase in pressure in the lumen 80, the catheter wall portion 70a expands to open the ports 74 and allows fluid to flow from the lumen 80 and into the body as generally illustrated in FIGS. 7E,F. When the wall portion 70a expands, it forms passageways 86 extending from the lumen 80 to the ports 74.