这压抑器Labii Demerioris肌肉是一个四面的面部肌肉，位于颚区域，将下唇向下和侧面绘制。
源于下颌内 - 在一个叫颌骨线的区域 - 这种肌肉插入下唇的皮肤，并用orbicularis oris肌肉混合。它延伸了血栓肌肉的纤维，而其自身的纤维与黄色脂肪组合。
又称Quadratus Labii Deverioris和Quadratus Menti，Depressor Labii Demerioris允许面部表情，展出小号和接吻。它是由其他肌肉的辅助，降低唇部：Risorius，Depressor Anguli Orias和Mentalis。
Supplied by the facial nerve, ailments affecting the depressor labii inferioris include myalgia (muscle pain), stroke, myopathy (muscle disease), strains, Bell’s palsy, lacerations, contusions, infectious myositis (inflammation of the muscle), tears, atrophy (loss of muscle), and neuromuscular diseases. Symptoms related to these disorders include decreased movement of the lip, loss of muscle control, paralysis, and muscle spasms.