Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the DIP joint or PD nerves.

Summary The response of horses, with solar pain in the dorsal or palmar aspect of the foot, to 6 or 10 ml local analgesic solution administered into the distal interphalangeal (DIP) joint was examined. Lameness was induced in 7 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot with set‐screws inserted into a custom‐made shoe. Horses were videotaped trotting before and after application of set‐screws and, in separate trials, after 6 or 10 ml local analgesic solution was administered into the DIP joint. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P ± 0.05) for horses with set‐screws applied to the angles of the sole and receiving 10 ml, but not 6 ml, local analgesic solution into the DIP joint. Scores were significantly lower (P<0.05) for all horses with set‐screws in the dorsal margin of the sole receiving either volume of local analgesic solution. Analgesia of the DIP joint was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole, and 10 ml local analgesic solution was more effective than 6 ml in desensitising these regions. The response of horses with solar pain to local analgesic solution in the DIP joint was influenced by the volume administered and the region of sole affected.

A 9-year-old American Quarter Horse mare was examined for evaluation of harsh respiratory sounds and coughing made during exercise and serosanguinous bilateral nasal discharge that had been present for 3 months. The mare initially was treated with ceftiofur sodium by the referring veterinarian (Naxel, Upjohn; 2.2 mg/kg IM q12h) for five days and then with procaine penicillin G (22.000 IU/kg IM q12h) and gentamicin sulfate (6.6 mg/kg IM q24h) for 7 days. Despite treatment, clinical signs did not change.The mare was in good physical condition and showed good appetite and normal behavior. Rectal temperature was 37.9ЊC; heart rate at rest was 36 beats per minute, and respiratory rate was 20 breaths per minute. The mare had a slight, odorless, bilateral mucohemorrhagic nasal discharge and mild inspiratory and expiratory sounds, but abnormal lung sounds were not heard during auscultation. Mandibular and retropharyngeal lymph nodes were not enlarged or painful on palpation. Tracheal rings felt firm and thickened on palpation. Nasal passages, guttural pouches, and the larynx appeared normal during endoscopic examination. Endoscopy of the trachea, however, revealed numerous granulomatous and partially erosive lesions in the proximal half of the trachea that had narrowed the tracheal lumen (Fig. 1). A cytological smear of the transendoscopical aspirate taken from the areas with granulomatous changes in the mucosa was highly cellular, with no evidence of bacteria, fungi, or neoplastic cells. Sixty percent of the cells were nondegenerate segmented neutrophils, and 40% were eosinophils. Fibrinogen concentration, results of a CBC, and serum biochemistries were within the reference range. Radiography showed an irregular tracheal lining extending the entire length of the tracheal lumen. Radiographic lesions within the lungs were not observed. Alpha-hemolytic Streptococcus spp. and a few colonies of gram-negative rods, most likely Actinobacillus sp., were cultured aerobically from tissue obtained by transendoscopic biopsy of granulomatous tracheal lesions.Intense infiltration of the submucosa with predominantly eosinophils, lesser numbers of neutrophils, and still fewer macrophages was found during histologic examination of the biopsy tissue. Multiple hypereosinophilic, 100-300-m foci with a central clear zone surrounded by degranulated eosinophilic granulocytes and nuclear debris (Splendore-

Summary We hypothesised that analgesia of the navicular bursa is not selective for the navicular apparatus; and that solar pain in some horses can be temporarily abolished or attenuated by analgesia of the navicular bursa. To test this hypothesis, we caused lameness in horses by inducing pain in the dorsal margin or the angles of the sole and then evaluated the ability of a local analgesic solution administered into the navicular bursa to attenuate lameness. The response of horses with solar pain in the dorsal or palmar aspect of the foot to 3.5 ml local analgesic solution administered into the navicular bursa was examined. Lameness was induced in 6 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot, with set‐screws inserted into a custom‐made shoe. Horses were videotaped trotting before and after application of set‐screws and after administering 3.5 ml local analgesic solution into the navicular bursa. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P<0.05) for all horses with set‐screws applied to the dorsal margin of the sole after administration of local analgesic solution into the navicular bursa. In conclusion, analgesia of the navicular bursa was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole. Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the navicular bursa.

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