Case history: An 8.5-month-old male Rottweiler was presented with chronic, non-localisable, right forelimb lameness.
Clinical findings: Survey radiographs revealed panosteitis in the right antebrachium and an irregularly marginated radiolucency on the lateral aspect of the proximal left humerus. The tendon of insertion of the left infraspinatus muscle was enlarged, some tendon fibres ended prematurely in a cluster of mineralised particles, and there was a large bony defect at the point of insertion.
Diagnosis: Probable avulsion of the left infraspinatus tendon.
Clinical relevance: This case was particularly unusual due to the marked prominence of the lesion without lameness of the left forelimb. Avulsion of the infraspinatus tendon is poorly described in the veterinary and medical literature.