Many years ago, while conducting research into the osteology of the hand, I spent time examining bony specimens and radiographs across various primate species. This work took me to the British Museum (Natural History) in London to study skeletal remains, and subsequently to London Zoo, where I was permitted to search through their extensive radiographic archives. One particular radiograph remains etched in my memory: the hand of a lar gibbon.
The image revealed an old trauma. At some point, the gibbon had suffered a severe fracture of a middle phalanx—I cannot recall if it was the index or middle finger, though both are notably prominent in this species. In the course of the injury, the distal segment of the finger had rotated ninety degrees, leaving the broken ends entirely unaligned. The resulting configuration was T-shaped: the proximal phalanx and the proximal half of the middle phalanx formed the vertical upright, while the distal half of the middle phalanx and the distal phalanx itself formed the crosspiece. Most striking was the presence of a robust fibrocartilage callus at the junction, firmly bridging the two disparate ends of the bone.
From a biomechanical perspective, such a deformity is significant. Given that lar gibbons rely on a specialized "hook grip" for brachiation, a T-shaped finger would have been a substantial mechanical hindrance. Yet, the animal clearly survived long enough for complete ossification to occur, suggesting a remarkable level of adaptation to its impaired mobility.
This specimen serves as a vivid illustration of how the biological healing process proceeds with total indifference to alignment. While the healing of displaced fractures is well-documented—frequently appearing in the archaeological record—most cases retain at least a rudimentary longitudinal orientation. Humans have recognized the necessity of orthopedic reduction since antiquity; the Edwin Smith Papyrus, a medical treatise dating to approximately 1600 BC (and likely reflecting practices from centuries earlier), describes the manual manipulation of fractures.
The gibbon’s finger, however, achieved a state of complete union despite being as misaligned as is physically possible. It prompts a reflection on the nature of medical "success." In modern orthopedics, success is defined by the restoration of anatomical alignment and function. Biologically, however, success is simply union and survival. The callus does not care for the aesthetic or the mechanical ideal; it merely seeks to close the gap.
I neglected, perhaps foolishly, to check the date on that radiograph. During a gap year after leaving school I worked at London Zoo, albeit in the modest confines of the gift shop. Each morning and evening, my commute took me past the gibbon enclosure. I often wonder if the very individual with the T-shaped finger was among those swinging beside me as I walked to and from work.
