While courts have long allowed custom-made medical illustrations depicting personal injury to be presented as evidence in legal cases, the issue of whether they have a legitimate place in the courtroom is surrounded by ongoing debate and misinformation. Some opponents of their general use argue that while illustrations are sometimes invaluable in presenting the physical details of a personal injury, in all cases except those involving the most unusual injuries, illustrations from medical textbooks can be adequate. Most injuries, such as fractures and whiplash, they say, are rather generic in nature—certain commonly encountered forces act on particular areas of the body in standard ways—so they can be represented by generic illustrations.

Another line of complaint stems from the belief that custom-made illustrations often misrepresent the facts in order to comply with the partisan interests of litigants. Even some lawyers appear to share a version of this view, believing that such illustrations can be used to bolster a weak case. Illustrators are sometimes approached by lawyers who, unable to find medical experts to support their clients' claims, think that they can replace expert testimony with such deceptive professional illustrations. But this is mistaken. Even if an unscrupulous illustrator could be found, such illustrations would be inadmissible as evidence in the courtroom unless a medical expert were present to testify to their accuracy.

It has also been maintained that custom-made illustrations may subtly distort the issues through the use of emphasis, coloration, and other means, even if they are technically accurate. But professional medical illustrators strive for objective accuracy and avoid devices that have inflammatory potential, sometimes even eschewing the use of color. Unlike illustrations in medical textbooks, which are designed to include the extensive detail required by medical students, custom-made medical illustrations are designed to include only the information that is relevant for those deciding a case. The end user is typically a jury or a judge, for whose benefit the depiction is reduced to the details that are crucial to determining the legally relevant facts. The more complex details often found in textbooks can be deleted so as not to confuse the issue. For example, illustrations of such things as veins and arteries would only get in the way when an illustration is supposed to be used to explain the nature of a bone fracture.

Custom-made medical illustrations, which are based on a plaintiff's X rays, computerized tomography scans, and medical records and reports, are especially valuable in that they provide visual representations of data whose verbal description would be very complex. Expert testimony by medical professionals often relies heavily on the use of technical terminology, which those who are not specially trained in the field find difficult to translate mentally into visual imagery. Since, for most people, adequate understanding of physical data depends on thinking at least partly in visual terms, the clearly presented visual stimulation provided by custom-made illustrations can be quite instructive.