Ultrasonography of theHarderian gland in the rabbit, guinea pig, and chinchilla

Abstract

AbstractObjectiveTo evaluate theHarderian gland in rabbits, guinea pigs, and chinchillas usingB‐mode ultrasound and to determine normal size and changes in size and/or location in normal and diseased eyes and orbits by ultrasonographic measurements.ProcedureNormalHarderian glands were evaluated ultrasonographically in 20 rabbits, 10 guinea pigs, and eight chinchillas. TheHarderian gland was measured ultrasonographically in horizontal and vertical planes. NormalHarderian gland sizes were then compared with sizes in 27 rabbits, 13 guinea pigs, and three chinchillas that had exophthalmos.ResultsHarderian glands in normal rabbits were 0.69 ± 0.07 cm (mean value ± SD) horizontally and 1.33 ± 0.14 cm vertically. Harderian glands in normal guinea pigs were 0.58 ± 0.05 cm horizontally and 0.61 ± 0.10 vertically. In normal chinchillas, theHarderian glands were 0.53 ± 0.04 cm horizontally and 0.53 ± 0.03 cm vertically. Harderian glands were significantly larger in the vertical plane in rabbits with exophthalmos (P = 0.001) and in the horizontal plane in guinea pigs with exophthalmos (P = 0.018). Harderian glands of rabbits with exophthalmos were significantly larger in both diseased and healthy glands in both planes compared with those of normal rabbits. Guinea pigs and chinchillas with exophthalmos had largerHarderian glands bilaterally in only the vertical plane.ConclusionsUltrasonography is a valuable diagnostic imaging technique to evaluate theHarderian gland in the rabbit, guinea pig, and chinchilla. Retrobulbar pathologic processes cause enlargement of theHarderian gland, which may be attributable to inflammation or possible obstruction of the excretory ducts.