The muscles associated with the abnormal clavicles are underdeveloped. The patient's neck appears long the shoulders are narrow and show marked drooping The absence or hypoplasia of the clavicles leads to an unusual mobility of the patient's shoulders. In some instances, the patient can approximate the shoulders in front of the chest (Fig. 14.6). Although the clavicular defects result in variations of the associated muscles, function is remarkably good.