Infraspinatus muscle contracture in a working dog.

A five-year-old Border Collie bitch was presented to Massey University Small Animal Clinic, for examination of a right forelimb lameness of three months duration. The distal forelimb was deviated laterally, there was limited mobility of the shoulder joint, and the animal showed gait abnormalities. Marked atrophy of the infraspinatus, supraspinatus and deltoideus muscles were present. Contracture of the infraspinatus muscle caused the lameness, and tenotomy of the infraspinatus tendon resulted in restoration of a normal gait. Although the exact aetiology is unknown, several possibilities are discussed.