ArtiFacts: Creating a 3-D CAD Reconstruction of the Historical Roman Capua Leg

From the Column Editor,

ArtiFacts examines what historical materials and past cultures can tell us about the practice of orthopaedic medicine. This month’s guest column takes a slightly different tack. It is also useful to sometimes reverse-engineer historical solutions to better understand how a problem was solved. This type of history-inspired research is always valuable because our ancestors were by no means less intelligent or less creative, and some of their concepts can even inform current research. None are more suited to illustrate this point than Andreas Otte MD and his team from Offenburg University, Germany. Their primary research focuses on the field of intelligent neuroprosthetics.

This month, Prof. Otte and his team detail how they created a 3-D CAD reconstruction of the Roman Capua leg, one of the earliest known prosthetic limbs. As Otte et al. note in the column below: “The ancient Capua leg indicates that the people of those days did not create primitive aids, but carefully thought about limbs and developed them on a highly technical level.”

— Alan J. Hawk BS

The Capua leg is one of the earliest known prosthetic limbs. It was discovered in the winter of 1884-1885 during excavations in historic Capua, a few kilometers from the present-day Italian town of Santa Maria Capua Vetere in Campania. The Capua leg was located next to a male skeleton with a missing lower right leg; an associated artificial foot was not found, perhaps because it was made of precious metal and had not been buried there by heirs or because it had been stolen by grave robbers. Other objects interred there, in particular vases, helped to date the finding to approximately 300 BCE.

The Capua leg was mentioned for the first time in a report of the Bulletino dell'Instituto di Correspondenza Archeologica in 1885 [3]: “Excavations of Santa Maria di Capua (from letters from A. Bourgiognon to G. Hensen): I give you the news of a very interesting monument recently discovered in Santa Maria di Capua. It is an artificial leg, inside of wood from the ankle to about the knee, covered with bronze, which protrudes 15 centimeters above the wood. The empty space thus created was undoubtedly intended for the upper part of the leg resting there. Then, attached to the upper part of the bronze are two or three iron holders in the form of eyelets, which apparently attached the inner leg to the thigh and perhaps served as hinges. The tomb where the leg was found contained a jar with red figures of recent age and in the Capuan style. The owner of the monument is Mr. Bernardo Califano.”

Just 1 year later, in 1886, the Royal College of Surgeons (despite laws against the export of antiquities from Italy at the time [4]) acquired the prosthesis and transferred it to London, where it was destroyed in a German air raid in 1941. Fortunately, however, a copy of the Capua leg was made as early as c. 1910, although it is not quite true to the original.

The little that is known about the original Capua leg comes mainly from two German medical historians: Karl Sudhoff (1853-1938) and his academic student Walter von Brunn (1876-1952); they were also in exchange with their English colleagues of the time, Prof. Arthur Keith (London) and Dr. Charles Singer (Oxford), who sent them photographs, measurements, and sketches of the original prosthesis [4-7].

Based on the above historical descriptions, measurements, and photographs (Fig. 1), we have attempted to reconstruct the artificial leg (Fig. 2) using three-dimensional (3-D) computer-aided design (CAD) [2]. Because not all dimensions of the original Capua leg have been transmitted, contemporary anthropometric data of DIN (Deutsches Institut für Normung [German Institute for Standards]) 33402-2:2005-23 and certain geometric assumptions were included for the reconstruction. Therefore, the reconstruction certainly deviates a little from the original Capua leg in its form. Nevertheless, it gives a good and realistic impression of the artistry of the Etruscan bronze workshop of that time.

Fig. 1.

Copy of the Capua leg. Credit: Wellcome Collection gallery (Science Museum, London): https://wellcomecollection.org/works/kyjgqfuh CC-BY-4.0

Fig. 2.

Our 3-D CAD reconstruction is shown. Credit: Offenburg University, Germany.

The wooden core of the original Capua leg “had nearly all crumbled away” [1], only a sketch from 1920 by Dr. Singer exists, which was reprinted in von Brunn´s article in 1926 [7]. Based on this sketch, we reconstructed the wooden core construction longitudinally (Fig. 3). Our transparent 3-D model also shows the wooden core and the bronze sheathing (Fig. 4), which was attached to the wooden core by means of rivets [7] and protrudes 15 cm above the wood [2].

Fig. 3.

The longitudinal section of our 3-D CAD reconstruction is shown. A first sketch of the longitudinal section was created by Dr. Charles Singer, 1920, and was reprinted in 1926 [7]. Credit: Offenburg University, Germany.

Fig. 4.

Transparent sheathing and a visible wooden core can be found in our 3-D CAD reconstruction. Credit: Offenburg University, Germany.

We hope and believe this reconstruction conveys the beautiful and, even by today’s standards, artistic workmanship of this prosthesis, while rendering more transparent the complex and elaborate inner construction of the wooden core. Creating transparent 3-D CAD models of archaeological findings can help historians or just those interested in history better understand the mechanism of prosthetic findings of the past and may inspire developers of future prostheses. The ancient Capua leg indicates that the people of those days did not create primitive aids, but carefully thought about limbs and developed them on a highly technical level. It may also be of interest to surgeons, as it was made and successfully worn at a time when amputations were usually fatal, although the present one must have taken place just below the patella in the upper third of the lower leg.