depressor anguli oris absence

Introduction Depressor anguli oris muscles is a paired triangular muscle that expands from the mental tubercle of the mandible to the angle of the mouth. It belongs to the buccolabial group of facial muscles also with levator labii superioris alaeque nasi, levator labii superioris, zygomaticus major, zygomaticus minor, levator anguli oris, risorius, depressor labii inferioris…