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.
Trigonometry is about angles and triangles, there are relationships between the angles and the ratios of the lengths of side of the triangles. These ratios are represented by functions such as sine and cosine, which occur widely in mathematics and physics, even in fields which don't initially appear to be related to physical triangles.