Some normal variations of knee arthrograms and their anatomical significance.

Knees obtained after amputation were fixed with formalin after the joint space was distended with air. The joints were then either dissected or frozen and sectioned vertically with a band saw in planes comparable to those visualized during arthrography. By comparing these anatomical specimens and arthrograms, the anatomical explanations for some normal variations visible or arthrograms could be identified. These variations included the appearance of the popliteus tendon and the posterior part of the lateral meniscus, the air-filled cul-de-sac posterior to the medial meniscus, and the interconnections of the joint space and the gastrocnemius and semimembranosus bursae.