Anatomy of the Inferior Orbital Fissure: Implications for Endoscopic Cranial Base Surgery

Abstract

Considering many approaches to the skull base confront the inferior orbital fissure (IOF) or sphenomaxillary fissure, the authors examine this anatomy as an important endoscopic surgical landmark. In morphometric analyses of 50 adult human dry skulls from both sexes, we divided the length of the IOF into three segments (anterolateral, middle, posteromedial). Hemotoxylin- and eosin-stained sections were analyzed. Dissections were performed using transnasal endoscopy in four formalin-fixed cadaveric cranial specimens (eight sides); three endoscopic approaches to the IOF were performed. IOF length ranged from 25 to 35 mm (mean 29 mm). Length/width of the individual anterolateral, middle, and posteromedial segments averaged 6.46/5, 4.95/3.2, and 17.6/ 2.4 mm, respectively. Smooth muscle within the IOF had a consistent relationship with several important anatomical landmarks. The maxillary antrostomy, total ethmoidectomy approach allowed access to the posteromedial segment of the fissure. The endoscopic modified, medial maxillectomy approach allowed access to the middle and posterior-medial segment. The Caldwell-Luc approach allowed complete exposure of the IOF. The IOF serves as an important anatomic landmark during endonasal endoscopic approaches to the skull base and orbit. Each of the three segments provides a characteristic endoscopic corridor, unique to the orbit and different fossas surrounding the fissure.

Endoscopic endonasal study of the cavernous sinus and quadrangular space: Anatomic relationships

“…The anteromedial triangle is bordered superiorly by V1, inferiorly by V2, and anteriorly by an imaginary line connecting the superior orbital fissure and foramen Rotundum representing the maxillary strut. [20][21][22][23][24] The anterolateral triangle is bordered superiorly by V2, inferiorly by V3, and anteriorly by an imaginary line connecting the foramina rotundum and ovale. Parkinson's triangle is bordered superiorly by the trochlear nerve, inferiorly by the V1, and posteriorly by a line on the tentorial edge.…”

Abnormal anatomy of inferior orbital fissure and herniation of buccal fat pad

“…The fissure is a linear defect with a reported width of about 5 mm anteriorly, tapering to about 2.4 mm posteriorly. 1 In our case the width was 5.6 mm, and its anterior margin was 16.2 mm from the infraorbital rim. These are consistent with the measurements reported previously.…”

“…: +44 07780682522. tapering to 2.4 mm posteriorly. 1 It communicates inferiorly with the pterygopalatine, infratemporal, and temporal fossas, and the masticator space.…”

Anatomía endoscópica de la unidad estructural Fisura orbitaria inferior - Músculo de Müller en la Junción órbito selar medial y su importancia quirúrgica

“…Los segmentos de la misma permiten establecer corredores quirúrgicos específicos a las diferentes aéreas contiguas a la FOI, según mostramos en otra publicación enmarcada en nuestra tesis (14) . Cuando utilizamos una vía endoscópica endonasal con apertura del seno maxilar (antrostomía), el segmento posteromedial es lo primero en ser visualizado.…”