Catheter assemblies are described having a catheter hub with a catheter tube and a needle hub with a needle projecting through the catheter tube. The catheter hub has a valve or a septum for stopping or slowing down the flow of fluid in or out of the catheter hub when the valve or septum is closed. The valve or septum has an exposed proximal wall that enables the valve to be wiped or cleaned with an antiseptic solution. The valve further has a cavity for receiving at least part of a needle guard, which is incorporated for preventing accidental needle stick with the needle tip.