Surface anatomy is the study of the body's external features, such as the hands, the feet and the legs. Certain features are labeled as regions based on the bones or muscles they cover. For example, the mastoid region is the area covering the mastoid bones of the ear.
Most abnormalities in surface anatomy features can be detected by sight. For example, doctors can tell that lymph nodes are swollen by the presence of bulges in the neck area. Further testing of such symptoms is critical to the diagnosis of life-threatening conditions such as lupus, human immunodeficiency virus and various types of cancer.