Injuries of the thoracic limb may present as a wing droop or an inability to fly (Fig 1). Injuries of the pelvic limb may present as lameness, unequal weight bearing, and/or an uneven grip.
Know–or review–avian anatomy before beginning the physical examination (Fig 2-Fig 4). The bird’s appendicular skeleton is an example of fusion and simplification. The propatagium is an important ligament that runs from the shoulder to carpus. This ligament may be palpated within the leading edge of the wing web or patagium (Fig 5).
|Manus||Major and minor digits|
|Metacarpus||Major and minor metacarpal bones that are fused proximally and distally..|
|Alula||A carpal bone that extends off of metacarpal bone III. The alular carpal bone as well as the alular feather are important in maneuvering.|
|Antebrachium||The ulna is the larger bone.|
|Humerus||Curvature of the humerus varies greatly among bid species.|
|Pectoral girdle||The bones of the pectoral girdle are the clavicle, coracoid, and scapula.|
|Femur||A short, stout bone. The avian hip joint is relatively shallow and abducts only a very small amount.|
|Patella||The presence of a patella will vary with the species.FibulaLateral to the tibiotarsus. This bone is fused proximally with the tibiotarsus, and its presence will vary with the species.|
|Tibiotarsus||The avian hock joint is blissfully simple when compared to mammals. The tibiotarsus develops embryologically from a fusion of the tibia and the proximal row of tarsal bones.|
|Tarsometatarsus||This bone develops embryologically from a fusion of the metatarsal bone and the distal row of the tarsus.|
|Digits||Digit #1 or the hallux is directed caudally. Digits 2, 3, and 4 are directed cranially with digit # 2 located medially and digit #3 in the most lateral position.|
Although the normal, healthy bird may be restrained manually, injured birds are at great risk for exacerbation of their injuries (Fig 6). Consider general anesthesia when orthopedic injury is suspected. Careful palpation may be performed at the same time as survey radiographs are performed.
Physical examination of the wing
To carefully examine the wing, first determine that the wing is capable of full extension (Fig 7). Grasp the wing at the carpus with the fingers extended over the wing web or patagium while supporting the elbow (Fig 8).
Palpate the wing from digits to shoulder taking each joint through passive range of motion. Also be sure to run a finger along the wing web. Any disruption of the wing web disrupts the avian airfoil and can therefore remove the ability to achieve flight. Also carefully palpate the axillae for any swellings.
Never get in a tug of war over the wing. If the bird struggles strongly, fold the wing back against the body to prevent injury.
Physical examination of the pelvic limb
Note the degree of strength in the bird’s grip. Check the plantar surface of each foot for redness, swelling, or ulcerative lesions. Palpate each leg starting at the toes and moving up the limb, taking each joint through a passive range of motion. Never hold the leg just by a toe as this can cause injury. Handler or examiner should always support the limb by grasping the tarsometatarsus or by resting a hand around the stifle.
Brown RE, Baumel JJ. Anatomy of the propatagium: The great horned owl (Bubo virginianus). Journal of Morphology 219(2):205-224, 1994.
King AS, McClelland J. Birds: Their Structure and Function, 2nd ed. WB Saunders Company; 1983.
Orosz SE. Anatomy of the musculoskeletal system. In: Altman RB, Clubb SL, Dorrestein GM, Quesenberry K (eds). Avian Medicine and Surgery. Philadelphia: WB Saunders Company; 1997. Pp. 517-522.
Orosz SE, Ensley PK, Haynes CJ. Avian Surgical Anatomy. WB Saunders Company; 1992.
Proctor NS, Lynch PJ. Manual of Ornithology: Avian Structure and Function Yale University Press; 1998.