title: The Sihler staining study of the infraorbital nerve and its clinical complication.
abstract: The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement.
authors.affiliation: From the *Department of Anatomy, College of Medicine, Dankook University, Choenan; †Department of Occupational Therapy, College of Health and Welfare, Woosong University, Daejeon; and ‡Division in Anatomy and Developmental Biology, Department of Oral Biology, College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: Hun-Mu
authors.initials: HM
authors.lastname: Yang
authors.forename: Sung-Yoon
authors.initials: SY
authors.lastname: Won
authors.forename: Young-Il
authors.initials: YI
authors.lastname: Lee
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Kyung-Seok
authors.initials: KS
authors.lastname: Hu
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000368:Aged; D059925:Anatomic Landmarks / Q000033:anatomy & histology; D002102:Cadaver; D002697:Chloral Hydrate / Q000737:chemistry; D004396:Coloring Agents; D004210:Dissection; D005143:Eyelids / Q000294:innervation; D005145:Face / Q000294:innervation; D005154:Facial Nerve / Q000033:anatomy & histology; D005260:Female; D005990:Glycerol / Q000737:chemistry; D006416:Hematoxylin; D006801:Humans; D008046:Lip / Q000294:innervation; D008297:Male; D008340:Mandibular Nerve / Q000033:anatomy & histology; D008442:Maxillary Nerve / Q000033:anatomy & histology; D009666:Nose / Q000294:innervation; D009915:Orbit / Q000294:innervation*; D013194:Staining and Labeling; D014276:Trigeminal Nerve / Q000033:anatomy & histology
chemical_list: D004396:Coloring Agents; D002697:Chloral Hydrate; D005990:Glycerol; D019342:Acetic Acid; D006416:Hematoxylin