Depressor labii inferioris is a muscle in the human body located in the lower lip area. It helps in controlling the movement of the lower lip and the corner of the mouth. Additionally, it is responsible for bringing the lower lip downwards and outwards. This muscle has several synonyms based on its function and location. Some of the synonyms for the depressor labii inferioris include inferior lip muscle, depressor anguli oris, buccinator muscle, platysma muscle, and mentalis muscle. These muscles work together to control the movement of the mouth and help in speech, eating, and other daily activities that involve the lips.