dissection

views updated May 21 2018

dissection of the human body is the act or art of cutting open the body in order to display and study the topographical anatomy and structure of its parts. It has its origins in antiquity. The evolution of the practice of dissection is a curious history of heroic academic endeavour, ingenuity, artistic idealism, romance, and iniquity. Claude Bernard, the French physiologist, rightly described anatomy as the basis of all physiology. Without a proper understanding of both there could never have been a scientific approach to the study and practice of medicine.

The story of the systematic dissection (anatomizing) of human corpses really begins in Alexandria (c.300–250 bc). It was here that anatomy first became a recognized discipline and that a proper systematized description of the structure of the human body was made. This was largely due to the work of Herophilus and Erasistratus. Herophilus is universally acknowledged as the ‘father of anatomy’ and is believed to be the first person to have performed a public dissection of the human body. He is thought to have performed approximately 600 dissections during his career, and it is alleged that some of these were vivisections (dissections of live persons) of condemned criminals. His contemporary, Erasistratus, also performed dissections. Together they made significant contributions to the study of abdominal and pelvic viscera, vascular anatomy, and neuroanatomy. Following the decline of Alexandrian science, the seat of serious anatomical study shifted to Rome. Here, Galen of Pergamum (129–216 ad) was the pre-eminent anatomist. Galen based his anatomical observations solely on animal dissections, and made the serious misjudgement of inferring that human anatomical features were identical to those in animals. Galen's authoritarian teaching held powerful sway throughout his lifetime and for a considerable period thereafter, resulting in the propagation of many erroneous concepts. For over a thousand years following Galen's death, there was a virtual cessation of any form of original anatomical inquiry. The practice of dissection had stopped altogether, chiefly due to contemporaneous religious proscriptions. This period of general intellectual stagnation is termed the Dark Ages. The resumption of the exploration of human anatomy by dissection, and the scientific impulse to verify or challenge Galenic doctrine, were part of the general intellectual reawakening (the Renaissance) that commenced in Italy during the thirteenth and fourteenth centuries and spread rapidly through the rest of Europe. The proliferation of this intellectual activity owed much to the many universities which were established in Italy and elsewhere in Europe, notably those in Salerno, Bologna, Padua, Florence, Louvain, Paris, and Montpelier. There is evidence that human post-mortem examinations were conducted in Bologna towards the end of the thirteenth century. These, however, were done not primarily for anatomical study, but to ascertain the cause of death. The first comprehensive human dissection to be done in post-Alexandrian times was performed in Bologna, in 1315 ad, by Mondino de Luzzi, a professor of medicine at the university in Bologna. In the following year he published his treatise, Anathomia, which reads remarkably like a practical dissection manual. Mondino's dissections were public events. He performed these in person and was largely responsible for restoring to anatomy its original respectability and status as a recognized discipline. None of Mondino's successors in Bologna made any significant contribution to anatomical knowledge.

The next milestone in the history of dissection occurred in 1543, when Andreas Vesalius, a young professor of anatomy in Padua, published his masterpiece De Humani Corporis Fabrica Libris Septem (‘the seven books on the fabric of the human body’). This was an exhaustive and systematically classified compendium of anatomical observations, sumptuously illustrated with accurate depictions of dissections based on Vesalius' vast personal experience, and laying to rest all Galenic misconceptions. Vesalius was largely responsible for inspiring the modern scientific study of topographical anatomy based upon direct observation at dissection, as opposed to the traditional ecclesiastical method of interpreting the written word. Realdus Columbus, Gabriel Fallopius, and Heironymus Fabricius continued the Vesalian anatomical tradition in Padua. Between the thirteenth and seventeenth centuries, Bologna and Padua (principally the latter) were the leading centres of anatomical study in the world.

It is generally acknowledged that Joannes Caius, a colleague of Vesalius, was the first to popularize the study of practical anatomy by dissection in England. Caius taught anatomy in Cambridge. However, neither Caius nor any of his immediate successors made any original contributions, and anatomical study in England was generally barren until the advent of William Harvey. Harvey's great intellectual triumph, De moto cordis et sanguinis, was published in 1628, and proved conclusively the circulation of blood. He reached his findings ‘by reason and experiment’ based on observations made in the course of dissecting several bodies, including those of his own father and sister (post-mortem) — a most unusual manifestation of clinical detachment.

During the fifteenth century, in the wake of the revival of anatomical dissection, there appeared a movement in Western art toward accurate representation of the human form. Prime among the exponents of this new school of naturalism in art were Leonardo da Vinci, Michelangelo Buanorroti, Albrecht Durer, Andrea Mantegna, and Andrea Verrocchio. Such was their obsession for scrupulous anatomical accuracy in their artistic depictions that they took to performing elaborate dissections (often in collaboration with eminent anatomists of the day) to enhance their understanding of the structure of the human body.

Availability and procurement of cadavers

Until the eighteenth century, the only lawful source of cadavers for dissection was the gallows. In Italy, papal consent was necessary before the corpse of an executed criminal could be dissected. In Scotland and in England royal assent was required in order to dissect the bodies of hanged felons. These legitimate dissections were intended as nominated public events and were conducted in large halls or amphitheatres. From the early eighteenth century onwards, anatomical theatres, specifically designed for dissection, were built in many of the major centres of anatomical study in Europe, including Leyden, Dublin, Edinburgh, London, Paris, and Louvain. These theatres were the forerunners of the modern-day dissection halls in medical schools. Towards the end of the eighteenth century, France repealed the law allowing dissection of executed criminals. Other European nations, including Britain, soon followed.

Thereafter only unclaimed bodies of persons dying in civil hospitals, prisons, and poor-houses could legitimately be used for dissection. However, the limited availability of legally-obtainable cadavers during the early days of dissection led to the unsavoury practice of ‘grave-robbing’ or ‘body snatching’ — the illegal exhumation and theft of freshly interred bodies for dissection. The scandal of ‘Burke and Hare’ who committed murder to supply corpses to anatomists, led to the very first act of legislation regulating the acquisition and use of cadavers for dissection in Great Britain, the Anatomy Act of 1832. In the present day, laws in different countries ensure that only such bodies as are legally bequeathed to medical institutions are used for dissection.

Preservation of cadavers

From the very earliest days of human dissection until relatively recently, a problem for anatomists was that there was no satisfactory method of preserving cadavers that would allow dissection to be carried out in an unhurried manner. The natural decomposition of the body, a rapid process, dictated the need for the dissection to be accomplished quickly and efficiently (in a matter of 3–4 days at most) before the unbearable stench of the putrefying cadaver made it impossible for the dissector to continue his task. In conditions of excessive humidity and warmth the problem was worse still, for which reason anatomists preferred to perform dissections during the winter months.

Robert Boyle's observation in the 1650s that decomposition of animal and human tissues could be prevented by immersing them in spirits of wine was a notable advance. This remained the principal method of cadaveric preservation until the latter half of the nineteenth century, when the antiseptic and preservative properties of formaldehyde were discovered. In the present day, preservation of cadavers (embalming) is usually accomplished by inserting tubes into a large artery and vein (usually the femoral artery and vein), washing out the blood, and then infusing a mixture of formalin (a 40% solution of formaldehyde), industrial alcohol, phenol, and glycerin. This mixture ensures that the body is both sterilized and preserved, and the glycerin prevents the tissues from becoming excessively hardened, thereby facilitating the process of dissection. As a result of these preservation techniques, there are several museums of human anatomy today containing permanent displays of beautifully dissected specimens. Among the finest and most comprehensive of these is the Wellcome museum of anatomy at the Royal College of Surgeons of England in London.

The study of human anatomy by dissection remains, today, an integral part of the basic undergraduate curriculum in medical schools the world over. A relatively recent innovation is the establishment of centres where experienced surgeons can revise and refine their anatomical knowledge of a particular surgical operation by cadaveric dissection, using precision instruments for incising tissues, operating microscopes for better visualization of structures, high-power drills for cutting bone, and endoscopes for viewing internal anatomy.

Vishi Mahadevan


See also anatomy; body snatches; Burke and Hare.

dissection

views updated May 14 2018

dissection (dis-sek-shŏn) n. the cutting apart and separation of the body tissues along the natural divisions of the organs and different tissues in the course of an operation. Dissection of corpses is carried out for the study of anatomy.