| Definition: |
A chiasma of facial muscles held together by fibrous tissue, located lateral and slightly superior to each angle of the mouth. It is important in moving the mouth, facial expression and in dentistry. It derives its motor nerve supply from the facial nerve, and its blood supply from labial branches of the facial artery. It is contributed to by the following muscles: orbicularis oris, buccinator, levator anguli oris, depressor anguli oris, zygomaticus major, risorius quadratus labii superioris, quadratus labii inferioris. |