The causes of erectile dysfunction are both physical and psychological.勃起机能障碍有身体上也有心理上的原因。Lesions are more common in internal organs but may rarely be seen as one or more cutaneous ulcers.机能障碍一般多见于内部器官，但偶尔也会以一处或多处皮肤溃烂的情况反映出来。He has no muscle function in his upper arms.他的上臂存在肌肉机能障碍。