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Ten stifles from 5 clinically sound adult horses were scanned by high-resolution ultrasound. Normal anatomic structures seen consistently included the subcutaneous tissue, the medial, middle and lateral patellar ligaments, the medial and lateral collateral ligaments, the femoral trochlear ridges, and menisci. Cruciate ligaments could not be visualized in the standing horse. Four stifle specimens obtained from 2 of these normal horses at necropsy were scanned in a water bath to create optimal technical conditions. The sonographic appearance of stifle specimens was similar to that found in live horses. Results from ultrasonographic examination of 3 horses with stifle abnormalities were described to illustrate some applications of ultrasonography in the evaluation of the equine stifle. In these horses, ultrasound was a valuable diagnostic tool to study joint effusion, synovial thickening, articular cartilaginous and subchondral defects, and soft tissue/bony injuries.

Abdominal discomfort in the foal presents a diagnostic challenge, because the small size of the foal precludes rectal palpation. Standing lateral horizontal beam abdominal radiographs using conventional techniques were evaluated as a diagnostic aid to identify the presence and location of gastrointestinal disorders in foals presented with colic. Forty foals were radiographed prior to surgery (20 foals), necropsy (7 foals), or clinical diagnosis (13 foals). Clinical, surgical, or necropsy findings were then correlated to radiographic findings. Gastrointestinal disease was accurately identified on radiographs as the source of colic in 25 of 26 foals that had surgical or postmortem confirmation. The site of disease, whether gastric, small intestinal, large intestinal, or a combination, was accurately determined from radiographs. Standing lateral abdominal radiographs were determined to be a valuable diagnostic aid in the foal presented with colic.

Radiography was used to evaluate 32 horses presented for puncture wounds into the navicular bursa. At the initial radiographic examination, 21 horses had no radiographic signs of osteomyelitis, while 11 did. The mean-time interval between injury and radiographic examination was 20.6 days for horses without evidence of osteomyelitis and 59.3 days for those with evidence of osteomyelitis. Radiographic signs of osteomyelitis of the navicular bone included flexor cortical destruction and irregularity of the flexor surface. Other abnormalities included pathologic fracture of the navicular bone, subluxation of the distal interphalangeal joint, or secondary joint disease. The lateromedial and palmaroproximal-palmarodistal oblique projections were most useful for identifying abnormalities of the navicular bone. There was a high correlation between horses that had positive presurgical radiographic signs and surgical findings. However, approximately 50% of horses that had negative radiographic findings initially had positive surgical findings. Ten of 21 horses with negative radiographic findings on initial examination had evidence of bony lesions when reevaluated from 3 weeks to 6 years later. Nine of 11 horses with radiographic signs of osteomyelitis on initial radiographic examination were euthanatized or had an unsatisfactory outcome. Seven of 10 horses with radiographic signs on reexamination were euthanatized. Thirteen of 20 horses with positive surgical findings for navicular bone infection were euthanatized or had an unsatisfactory outcome.

Two rare earth radiographic intensifying screen-film systems were compared with a calcium tungstate screen-film systems in a series of clinically oriented trials. The calcium tungstate screen-film system was subjectively judged to have the highest overall image quality, primarily because of its wide latitude. Several rare earth screen-film combinations produced radiographs of excellent diagnostic quality. In general, image quality was inversely related to screen-film speed, whereas radiation protection was directly related to screen-film speed. Medium-speed rare earth screen-film combinations resulted in reductios of scatter radiation on the order of 30 to 70 percent compared with the par-speed film combination. Recommendations are made regarding the use of specific rare earth intensifying screen-film combinations in small and large animal diagnostic radiography.

A New radiographic projection of the equine thrid metacarpal bone condyles and developed to aid detection and evaluation of ulcerative cartilaginous and osseous lesions on the MC III Papmar aspect. The most sccessful projection tried was a nonweight-bearing one with the leg extended. Subsequent clinical evaluation proved this projection to be significant in confirming and further delineating palmar lesions seen on weight-bearing lateromedial and flexed lateromedial radiographs. The new projection has also proved valuable in the complete evaluation of vertical MC III condylar fractures. It makes possible detection of fracture comminution at the condylar articular surface, fractures which cannot be seen on other projections.

The case records of 274 horses with fractures of the distal phalanx were reviewed. Fifty-two horses had bilateral forelimb fractures, for a total of 326 distal phalanx fractures. The fractures were classified into one of five previously described types, based on the radiographic anatomic configuration of the fracture. Solar margin fractures, which have been briefly described in other reports and previously classified as type V fractures, were identified in 132 horses. This type of fracture is distinct from other distal phalanx fractures. Due to the high incidence of solar margin fractures, these fractures were classified as a separate type (type VI). Follow-up radiographic examinations to assess fracture healing were available for 36 horses. Twenty-two horses with distal phalanx fractures (three type I, nine type II, two type III, one type IV, one type V, and six type VI) had radiographic evidence of complete bony union of the fracture at a mean of 11 months after injury. Eight horses with complete type II fractures involving the articular surface had bony union of the body and solar margin, but not the subchondral bone at the articular surface, a mean of 11 months after injury. Six horses (four type II and two type IV) had little radiographic evidence of bony healing during the follow-up period. All fractures that eventually healed had evidence of progression toward bony union by 6 months after injury.

Abnormal pulmonary radiopacities were identified in 13 racing horses in which a diagnosis of exercise-induced pulmonary hemorrhage (EIPH) had been confirmed. The lesions were in the caudal lung lobe in all horses; seven were on the right and three on the left, and the laterality for three could not be determined. In ten horses the opacities, which were large and peripherally located, obliterated the thoracophrenic angle. They merged with the silhouette of the diaphragm and had a circular or ovoid surface directed toward the hilum. The intensity of opacification of the consolidated areas varied, and they often were not sharply marginated. Dorsal displacement of the pulmonary arteries was noted in the region of the radiopacity in seven horses. Varying volumes of pleural effusion were observed in nine horses. Serial radiographic examinations were performed in seven horses. The pulmonary radiopacities cleared within ten days in two horses. In the remaining five horses, gradual resolution, characterized by a reduction in lesion size with improved margination, occurred during several months. The central region of the radiopaque lesion commonly had a patchy appearance, suggesting cavitation. Normal pulmonary vascular and interstitial markings were evident following complete resolution of these lesions. The cause of these abnormal pulmonary opacities has not been determined. Pathologic-radiologic correlations will be required to improve understanding of the pathophysiology of EIPH in the racing horse.