The subclavian is often injured by bone growths or a fracture of the tuberosity of the coracoid process of the scapula. In contact with the shoulder blade, he experiences severe trauma. This occurs when the shoulder girdle moves posteriorly from the midline of the neck (for example, when lifting a load with both hands). As a result, a sprain or tear of the subscapularis muscle tendon often occurs, and in more severe cases, the capsular ligamentous apparatus of the joint. In this case, the anterior upper corner of the scapula can slide back upward along the fossa formed as a result of trauma - the angle between the posterior angle of the scapula and the anterior plane of the clavicle decreases. With age, the risk of injury is lower, but nevertheless, the risk increases with the deposition of calcium salts in the area of the acromioclavicular joint (the scapula may slip upward).