Microsurgical Anatomy of the Orbit: The Rule of Seven

Abstract

The orbits are paired structures, located on the anterior part of the face. Morphologically, each orbit is a four sided pyramid with a posterior apex and anterior base. In the orbit, all openings are arranged around the base, apex or between the orbital walls. An anatomical characteristic of the orbit is that structures are arranged in groups of seven: there are seven bones, seven intraorbital muscles and seven nerves in the orbit. Tumors confined within the periorbita in the anterior two thirds of the orbit can often be approached extracranially, but those located in the apical area, and especially those on the medial side of the optic nerve, often require a transcranial approach. Thus, knowledge of orbital osteology is paramount in adequately choosing and performing an orbital approach. Understanding the critical topographical elements in this area helps to classify an orbital lesion and provides for a solid basis in choosing the most adequate intraorbital route for its treatment.

Microsurgical anatomy of the trigeminal nerve

“…It may also carry some sympathetic fibers to the globe and pupillary dilator (Rhoton, ). The supraorbital nerve may transmit autonomic fibers from the cervical sympathetic ganglia to the lobe and pupillary dilator (Martins et al, ).…”

“…The postganglionic parasympathetic motor fibers containing lacrimal secretomotor fibers, carried by the zygomatic branch of the maxillary division, which course along the lateral orbital wall, join the lacrimal nerve (Fig. D) (Shankland, ; Rhoton, ; Martins et al, ). The lacrimal nerve also conveys sensation from the area in front of the lacrimal gland.…”

Endoscopic transpalpebral approach for resection of an intraorbital intraconal cavernous angioma

“…Many surgical approaches are possible for orbital lesions, mainly depending on their location, each one with proper advantages and limits (Martins et al, 2011;Paluzzi et al, 2015).…”

Validity of the Lateral Supraorbital Approach as a Minimally Invasive Corridor for Orbital Lesions

“…Although the intraconal lesions are always intradural, the extraconal lesion can be either intradural or extradural (24) The intracanalicular lesions refer to those lesions lying at least partially within the optic canal (31). This understanding is paramount in classifying the orbital lesions and selecting the best approach providing good exposure of anatomic structures, preserving their function, and providing good cosmetic results (22).…”