A venous access port assembly having a housing with a discharge port, and a needle-penetrable septum. An interior reservoir is defined in the assembly, and a passageway extends from the reservoir through the discharge port. The needle access area of the septum includes a tactilely identifiable differentiation along the top surface thereof, such as a ridge, a recess, an X-shaped protrusion, a V-shaped groove, or a bipartite dome.