The humerus provides an important attachment site for the powerful muscles of flight in most avian species. Birds of prey, in particular, rely heavily upon flight to search, locate, and acquire their essential resources. To be able to successfully hunt and survive in the wild requires the strength and stability of the humerus to withstand the stressors applied during the mechanical forces produced by the large flight muscles. Furthermore, important soft tissues located at and near fracture sites may be damaged as a result from traumatic injuries, inadequate immobilization, as well as iatrogenic manipulation during the attempt to stabilize the fracture. Fractures occurring near joints may also be problematic.
The avian skeleton is modified for flight and the humerus provides important structural support during production of this movement. In order to apply appropriate clinical care to a fractured humerus, detailed knowledge of wing anatomy is essential.⁷ The proximal end of the humerus serves as an attachment point for the pectoralis and supracoracoideus flight muscles.⁴ In raptors intended for release, normal function is imperative and requires the humerus to maintain its normal length, rotation, and angular orientation.² Loss of normal function and flight can be described as an avian lameness¹; therefore, to restore normal mobility, the fractured humerus must be sufficiently repaired to withstand the forces applied by the large flight muscles during the generation of flight.
Fractures of the humerus occur commonly in birds of prey³˒⁶ and repair methods include non-invasive external coaptation such as the figure-of-eight bandage plus body band or surgical approaches.³ The ideal fracture repair method will achieve the best overall bone healing with minimal complications, and restores full mobility for a high rate of successful release.³˒⁵
- Beaufrère, Hugues. “A Review of Biomechanic and Aerodynamic Considerations of the Avian Thoracic Limb.” Journal of Avian Medicine and Surgery 23.3 (2009): 173-85. BioOne. Web. 28 Feb. 2013
- Bennett, R. Avery, and Alan B. Kuzma. “Fracture Management in Birds.” Journal of Zoo and Wildlife Medicine 23.1 (1992): 5-38. JSTOR. Web. 25 Feb. 2013.
- Muller, Margit Gabriele. “Orthopedic Problems and Surgery.” Practical Handbook of Falcon Husbandry and Medicine. New York: Nova Science, 2009. 285-307. Print.
- Proctor, Noble S., and Patrick J. Lynch. “The Skeleton.” Manual of Ornithology: Avian Structure & Function. New Haven: Yale UP, 1993. 134-36. Print.
- Redig, Patrick T. “The Use of an External Skeletal Fixator-Intramedullary Pin Tie-in (ESF-IM Fixator) for Treatment of Longbone Fractures in Raptors.” Raptor Biomedicine III: Including Bibliography of Diseases of Birds of Prey. By J. T. Lumeij and J. Poffers. Lake Worth, FL: Zoological Education Network, 2000. 239-53. Print
- Simpson, Greg N. “Wing Problems.” Manual of Raptors, Pigeons and Waterfowl. By Neil A. Forbes, Nigel H. Harcourt-Brown, and Peter H. Beynon. Ames: Iowa State UP, 1996. 169-79. Print.
- Zucca, Paolo, and John E. Cooper. “Osteological Aspects of the Falcon Wing.” Raptor Biomedicine III: Including Bibliography of Diseases of Birds of Prey. By J. T. Lumeij and J. Poffers. Lake Worth, FL: Zoological Education Network, 2000. 195-99. Print.