CEA test: Carcinoembryonic antigen test is to detect response to therapy in cancer patients, especially colon cancer, with normal range of less than 2.5 (less than 5 in heavy smokers). Note that a positive test may not always be indicative of cancer.
Os Trigonum Syndrome. An Os Trigonum is a small, extra bone found at the back of the ankle in approximately 5-10% of people. Often it goes completely unnoticed, not causing any problems.
Os trigonum on x-ray. Though irregular in shape, the talus can be subdivided into three parts. Facing anteriorly, the head carries the articulate surface of the navicular bone, and the neck, the roughened area between the body and the head, has small vascular channels.