The bodies, all of which are donated specifically for teaching anatomy, are preserved at the Medical Center in Indianapolis. "The embalming is begun by the funeral director wherever the person died; that process is completed at the Medical Center," Heersma notes. Following the initial stage of embalming, in which the blood is replaced as completely as possible with embalming fluid, the cadavers are immersed for about three months in a large tank filled with a fluid that further preserves them. Occasionally, Heersma says, he is called upon to do some remedial embalming--this procedure involves injecting a preservative fluid with a syringe into the tissue that is beginning to decompose. The principal chemicals used to preserve the cadavers are formaldehyde and phenol. All preservatives are "used in a low concentration because of the possible danger to those who have to be around the cadaver when it is used or dissected," Heersma says, noting that formaldehyde is classed as a potential carcinogen.
While students perform the dissections in the medical gross anatomy lab, the cadavers for the undergraduate lab are intended to be used for demonstration and are dissected by medical or graduate students during the summer. Since these cadavers must be reused for at least two semesters, "the dissection process can't go on, so it is a creative compromise between showing as much as you need to but preserving as much as you need to," Heersma explains.
When Heersma started working as the laboratory demonstrator for anatomy over fourteen years ago, he did a sample dissection to serve as a guide for the gross anatomy students. Now, however, the only dissecting he does is some clarification work on the cadavers prepared for the undergraduate class.
There has never been a severe shortage of cadavers during Heersma's tenure, but there have been times when the lab could not procure the desired ratio of male to females cadavers. If there were a shortage, more than the usual four students would have to work on each cadaver. Heersma notes that "what it usually comes down to is Anatomical Education perhaps accepting donors that they might otherwise not have accepted." The standard weight limit for acceptable cadavers is 200 pounds because of practical difficulties in using or embalming larger bodies. Another restriction, which cannot be relaxed, is a prohibition on certain conditions or causes of death. "There are several infectious agents, including the AIDS virus for which the survival due to incomplete embalming cannot be risked," Heersma says.
Heersma suggests that shortages might be avoided by further publicizing the need for the donation of bodies for use in teaching anatomy. "I have never heard of any reference anywhere or anyone saying that bodies might be needed for teaching anatomy to medical students," he states. "The cadavers are an essential part of the medical course and an important part of the undergraduate course." He has heard that some medical schools are now forgoing the use of real cadavers for computer imaging. "But it isn't the same experience," Heersma says.