A bone marrow aspiration assembly including an outer cannula assembly, an inner cannula assembly, and a flexible seal. The outer cannula assembly includes an outer handle and an outer cannula defining a first passageway and including a plurality of first openings between a first end and a second end of the first passageway. The inner cannula assembly includes an inner handle and an inner cannula defining a second passageway and is configured to be received within the first passageway. The inner cannula includes a plurality of second openings between a first end and a second end of the second passageway. The flexible seal is mounted to the inner handle and positioned such that the seal contacts the outer cannula assembly when the inner cannula assembly is in cooperation with the outer cannula assembly to create a substantially airtight seal therebetween.
