Abstract

The thoracic limb digits of 11 healthy juvenile Asian elephants (Elephas maximus) were evaluated radiographically to assess normal developmental anatomy. Parameters evaluated included the location(s) of centers of ossification, relative age at time of phalangeal ossification, and relative times of growth plate closure in the bones of the distal forelimb. Specifically, the third phalanx (P3) of each digit was evaluated, as well as the first (P1) and second (P2) phalanges of the third digit (D3). A retrospective evaluation of radiographs from juvenile elephants was also done to augment the data set. This study reports the methods used to obtain high-quality radiographs of the elephant foot, the locations of centers of ossification based on radiographic evaluation, and the relative times of growth plate closure within the digital bones. The settings used to obtain the radiographs used in this study for P3 are presented in Table 1. Radiographs of D3, P1, and P2 were obtained in a similar manner using a 45° angle for focal spot positioning. The kilovoltage power and milliampere seconds were adjusted as needed. Radiographic evaluation of the juvenile Asian elephants revealed variability in the shape of P3 based on age of the animal and degree of ossification of P3. The relative times of growth plate closure and number of ossifications were also determined. The information presented will help clinicians in radiographing elephants, interpreting foot radiographs, and recognizing normal versus abnormal anatomy. It will also help in aging juvenile elephants, investigating diseases and deaths, and recognizing normal patterns of toe and foot development.

Table 1. Radiographic techniques for the third phalange of the juvenile Asian elephant (Elephas maximus) forelimb using two film/cassette speed combinations

^aNumber of phalanges evaluated. Range represents minimum and maximum values recorded. All radiographs were done using the MinX 80 portable radiography machine, using a 45°angle for focal spot positioning.

Acknowledgments

The authors thank the College of Veterinary Medicine’s Resident Intramural Competitive Grants Program for financial support; the Radiology Department and Zoological Medicine Service at the University of Florida’s Veterinary Medical Center for technical assistance; and Zoo Atlanta and Feld Entertainment for the opportunity to work with their elephants and trainers.