Medical valve with a variable diameter seal

A medical valve assembly for use in inserting a medical device into a body vessel of a patient, comprising:

• a tube extending between a first tube end and a second tube end along an axis;
• a plunger plate extending radially from said second tube end of said tube;
• a valve housing surrounding said tube about said second tube end and extending from a first valve housing end to a second valve housing end;
• said valve housing including a flange extending radially inwards from said second valve housing end and disposed in spaced relationship with said plunger plate to define a distance extending therebetween;
• an elastomeric seal extending between said plunger plate and said flange and having an inner surface defining an inner diameter for use in establishing a variable seal of the medical valve assembly;
• a compression member disposed within said valve housing and biased against said plunger plate for compressing said elastomeric seal from a non-compressed condition to a compressed condition to decrease said inner diameter and establish a closed condition of the medical valve;
• and
• said inner surface of said elastomeric seal in said non-compressed condition having a plurality of planar portions and a plurality of radiused portions with adjacent ones of said plurality of planar portions interconnected with one of said plurality of radiused portions.