Angiography is invasive because it requires the injection of a radiopaque substance into the circulatory system. PET is invasive because it requires the injection of radioisotopes. Sonography, CT, and MRI are noninvasive because they require no injections, other breaks in the body surface, or probing of any body cavity.
Both internal and external anatomy are variable, so anyone being trained for careers involving patient examination, diagnostic imaging, surgery, and so forth must be well aware of this variability and familiar with the most common variations. He or she will then be less inclined to make false assumptions about a patient’s anatomy.
If the terms defining life are defined somewhat broadly, an automobile could be described as exhibiting organization (though it does not expend energy to maintain this order), a degree of chemical (if not biochemical) unity with other automobiles, metabolism (combustion of fuel), responsiveness (to the ignition switch, accelerator, etc.), and a degree of homeostasis (in thermostatically controlled systems). This shows that life is not defined by any single criterion but by a unique combination of properties. It shares many of the individual properties with nonliving things, but does not share all of them with any nonliving thing.
A monkey is not classified as human because it is not bipedal, it does not make tools (though students may not realize that chimpanzees are not monkeys), and it has not developed a large brain or a hominid level of speech. A horse is not classified as a primate because it lacks clavicles, two pairs of incisors, flat nails, forward-facing eyes, thumbs (much less opposable ones), and it has more than two mammary glands. Most students will not know all these aspects of horse anatomy (clavicles, incisors, or number of mammary glands) but should be able to infer at least some of them (lack of nails, thumbs, and forward-facing eyes).
Eponyms are uninformative; they do not describe anything of the form or function of a structure. Presumably most students would regard descriptive, noneponymous terms as being to their advantage. The committee named structures in Latin because it is a static and internationally neutral language, so it is relatively apolitical. Students might object to this, but if everyone in the world had a vote on the language in which to name things, anatomical terms might be in Chinese!
