Palpation is an important part of the physical examination; the sense of touch is just as important in this examination as the sense of sight is. Physicians develop great skill in palpating problems below the surface of the body, becoming able to detect things that untrained persons would not. Mastery of anatomy and much practice are required to achieve a high level of skill. The concept of being able to detect or notice subtle tactile signs and to recognize their significance or implications is called appreciating them (just as in general vocabulary one can speak of appreciating the importance of something). Nonetheless, some things are not palpable, which is why additional medical tests, such as medical imaging and laboratory tests, are often needed to make a diagnosis. However, many other problems "are" palpable. Examples include pulses, abdominal distension, cardiac thrills, fremitus, and various hernias, joint dislocations, bone fractures, and tumors, among others.