The shoulder joint is the most mobile of all main limb joints. While its primary motion is in a sagittal plane, the shoulder has a significant amount of abduction and adduction, and internal and external rotation. Its stability is ensured by the joint capsule, by its specialized bands (medial and lateral glenohumeral ligaments), and by large tendons located inside (eg, tendon of origin of the biceps brachii muscle) or immediately outside the joint (eg, supraspinatus, infraspinatus, teres minor, and subscapularis). Sprains or strains of all supporting structures of the canine shoulder have now been reported and the shoulder pathology resembles the pathology of the human shoulder that includes strains and tears of the rotator cuff muscles, adhesive capsulitis, and calcific tendonitis.