Abstract: A gland member within a medical valve is configured to have a substantially consistent or enlarging internal volume as the valve transitions from a closed mode to an open mode. To that end, the valve has a housing forming an interior containing a flow path, and a stationary post member within the interior. The post member has a lumen that is a part of the flow path. The lumen has an opening to the interior of the housing. The valve further includes a gland member circumscribing the post member to produce a variable volume region formed at least in part between the gland member itself and the post member. In addition, the variable volume region is a part of the flow path, while the gland member occludes the post lumen opening when in the closed mode. The variable volume region has an open volume (i.e., when the valve is in the open mode) that is no less than its closed volume (i.e., when the valve is in the closed mode).