An 18-year-old warmblood gelding was presented to Jeju National University Equine Hospital with chronic bilateral forelimb lameness. Navicular syndrome was suspected based on clinical findings, the hoof test, palmar digital nerve block, and radiographic results. Computed tomography (CT) was performed under general anesthesia. Bone cysts, enlarged vascular channels, sclerosis, and enthesophytes were identified in the navicular bone on CT images. Mineralization in the deep digital flexor tendon was also observed. CT can be a useful diagnostic tool for identifying lesions of the navicular bone and adjacent structures in horses. The horse was treated with an intra-bursal injection of triamcinolone and gentamicin. Lameness started to improve two days later and the horse was sound after two months of the injection. CT enabled us not only to diagnosis of navicular syndrome but also to determine the degree and extent of the lesions.

Keywords: navicular syndrome, computed tomography, horse