Heterotopic Ossification of the Adductor Muscles in Bald Eagles ( Haliaeetus leucocephalus )

Diseases of the musculature can be caused, for example, by alimentary or traumatic issues. In three bald eagles with painful lameness and/or a reduced range of the hip joint, a muscular disease was diagnosed via radiographic examination. The eagles were kept in a falconry and trained as demonstration birds, which were displayed on a gloved hand and flown in falconry education programs. The imaging revealed varying degrees of calcification of the adductors along the course of the puboischiofemoral muscle of the left hind limb in all cases. A histological examination of the affected musculature of one eagle confirmed the presence of a myopathy with muscle fiber atrophy, fibrosis, and metaplastic bone formation. Increased mechanical stress and injuries to the affected muscle groups are discussed as the cause of these alterations. The adductor muscles of the left leg of bald eagles in falconry husbandry appear to be particularly prone to muscular injuries and the development of heterotopic ossification. The healing process of such an injury with the stiffened musculature can lead to restrictions in the movement of the hip joint. Thus, the conscious and professional handling of the eagles is essential for maintaining the health of these birds.