A medical valve can include a housing that includes a sidewall and defines a chamber. The medical valve can include a septum coupled to the housing. The septum can include a proximal surface and a selectively openable closure positioned within the chamber. The medical valve can further include a plurality of projections that extend away from the sidewall and are configured to contact the proximal surface of the septum to oppose movement of a restricted portion of the septum in a proximal direction such that an aspiration cracking pressure required to open the closure to permit fluid flow through the septum in the proximal direction exceeds an infusion cracking pressure required to open the closure to permit fluid flow through the septum in the distal direction.
