The meningo orbital foramen (MOF) is located in the major wing of the sphenoid and near the lateral end of the superior orbital fissure (SOF), communicating orbit with the middle cranial fossa and allowing the passage of an anastomosis between the ophthalmic and middle meningeal arteries. Its prevalence varies from 6 to 82.9 % and may occur unilaterally or bilaterally, single or multiple, and may have a circular, ovoid or groove form. The aim of this study is to evidence the existence of MOF, describing its morphological characteristics in dry skulls of Chilean adults of both sexes. The present study analyzed 54 skulls containing both orbits, considering the following criteria: Existence, unilaterality or bilaterality, number of foramens by orbit, shape, location in relation to the horizontal baseline determined by the lateral end of the SOF, distance to the lateral end of the SOF and diameter and variations by sex. Measurements were made with nylon probe, compass dry point and digital caliper. Of the sample, 46.29 % presented MOF with a greater prevalence in female samples. In 28 % of the cases it was unilateral and in the other 72 % bilateral. The circular shape was predominant in 79.07 %, followed by the ovoidal 18 % and the groove form 2.33 %. The MOF was observed in 90.69 % on the horizontal baseline that determines the lateral end of the SOF and in 9.31 % in the same baseline. The average distance from the MOF to the lateral end of the SOF was 6.58 mm and the diameter of the MOF corresponded to 1.22 mm. Our results are consistent with similar studies. There were some minor differences observed in Indian, Asian and Pakistani skulls as well as some anatomical differences by sex. A better understanding of MOF plays an important role in anatomy, anthropology, ophthalmology, traumatology, medical imaging, surgery and human identification.

KEY WORDS: Orbit; Superior orbital fissure; Meningo orbital foramen; Ophthalmic artery; Middle meningeal artery.