Its medial fibers form the
angular head (also known as the
levator labii superioris alaeque nasi muscle) which arises by a pointed extremity from the upper part of the
frontal process of the
maxilla and passing obliquely downward and lateralward divides into two slips. One of these is inserted into the
greater alar cartilage and skin of the nose; the other is prolonged into the lateral part of the
upper lip, blending with the infraorbital head and with the
orbicularis oris. The intermediate portion or
infraorbital head arises from the lower margin of the
orbit immediately above the infraorbital foramen, some of its fibers being attached to the
maxilla, others to the
zygomatic bone. Its fibers converge, to be inserted into the muscular substance of the upper lip between the angular head and the
levator anguli oris. The lateral fibers, forming the
zygomatic head (also known as the
zygomaticus minor muscle) arise from the malar surface of the
zygomatic bone immediately behind the
zygomaticomaxillary suture and pass downward and medialward to the upper lip. ==Function==