superior labial nerve superior labial nerve the superior labial branches (labial branches), the largest and most numerous, descend behind the quadratus labii superioris, and are distributed to the skin of the upper lip, the mucous membrane of the mouth, and labial glands. superior labial nervedistribution of the maxillary and mandibular nerves, and the submaxillary gangliondetailsidentifierslatinrami labiales superiores nervi infraorbitalista98a14.2.01.063ta26245fma52986anatomical terms of neuroanatomy they are joined, immediately beneath the orbit, by filaments from the facial nerve, forming with them the infraorbital plexus.