The broad base of the cone is along the distal border of the navicular bone, while the pointed part of the cone extends into the center of the bone. It is my opinion that cones involving the distal border of the navicular bone are radiographically unimportant and are part of its normal physiologic processes. The radiolucent circular structure may also involve the central portion of the navicular bone. I believe that lollipops are a significant radiographic finding, indicative of a current, progressive, degenerative process. The size of either the lollipops or cones is, in my opinion, not important.
Cones are physiologically normal and lollipops are pathologic.
In addition to the lollipop-shaped radiolucencies in the navicular bone, occasional large cystic lesions in the central portions of the navicular bone also are significant changes. Figures 23 through 32 demonstrate the various types of cone and lollipop formations that can be seen in the navicular bone. Figures 31 and 32 also illustrate cystic or radiolucent areas in the central portion of the navicular bone. Figure 31 shows a large radiolucent area involving the middle 50 per cent of the navicular bone. Figure 32 shows a somewhat smaller radiolucent area in the central portion of the navicular bone.