abnormal levator nasolabialis muscle morphology absent levator nasolabialis muscle 2017-11-23T14:00:08Z absent levator nasolabialis MPheno.ontology missing the flat, thin muscle that lies beneath the skin on the lateral surface of the maxillary bone; it arises from the maxillary bone, over the dorsum of the nose, and runs cranioventrally to insert partly on the wing of the nostril and partly into the lateral part of the upper lip; it acts to dilate the nostrils and elevate and retract the upper lip MP:0030430