Abstract
Objective The aim of our study is to present the anatomical landmarks to perform an endoscopic
endonasal approach to the medial wall of the orbit (EEAMO).
Material and Methods We performed 14 complete nasal and orbital endoscopic dissections in 7 adult cadaveric
heads.
Results The EEAMO provides a surgical corridor between the medial rectus muscle superiorly
and the inferior rectus muscle inferiorly .The mean distance between the ethmoidal
crest and medial rectus muscle was 1.5 cm (range, 1.3–1.9 cm). The width of the medial
rectus muscle was 1.2 cm (range, 1–1.5 cm). The main vascular structure in this retrobulbar
space was the ophthalmic artery that crosses over the optic nerve in 86% of the cases.
In its intraorbital route, the anterior ethmoidal artery and the ethmoidal nerves
were situated inferior to the superior oblique muscle in all cases. The posterior
ethmoidal artery was found superior to it. We could identify the inferior division
of the oculomotor nerve in this surgical approach.
Conclusions The EEAMO allows adequate exposure of the space between the medial rectus muscle
and the inferior rectus muscle. The location of the ethmoidal crest of the palatine
bone, and its relationship with the medial rectus muscle, is a useful anatomical landmark
for this surgical approach.
Keywords
orbital - endoscopic sinus surgery - sinus anatomy - optic nerve
