The orbit: A re‐appraisal of the surgical landmarks of the medial and lateral walls

Abstract

The anterior ethmoidal foramen (AEF) and posterior ethmoidal foramina (AEF and PEF, respectively) on the medial wall and the cranio-orbital foramen (COF) on the lateral wall are used as landmarks in orbital surgeries. In surgery these foramina, the neurovascular structures they transmit and other orbital structures in close proximity need to be identified to minimise their risk of damage. Despite the clinical importance, the current understandings lack consistency in the precise location, microanatomy and morphology of the foramina. This study therefore aimed to document and analyze the microanatomy, location, and morphometric relations of the EF and COF to determine a standardized guideline to accessing the foramina. One hundred dry orbits were morphometrically analyzed, and a further six orbits were micro-dissected to determine the locations of the EF and COF. The orbital size dimensions were measured for each dry orbit and correlated with the morphometric distances. A complete morphometric and quantitative analysis showed the distances of the EF and COF to be variable, with greater variations observed in the incidence of the accessory EF and PEF distances in the medial wall, and in the presence of the COF and the accessory COF in the lateral orbital wall. Significant correlations were observed between the length of the medial orbital wall and some EF distances. This study is the first to suggest a standardized method of locating these foramina in the orbit irrespective of population and sex differences, in order to help improve clinical applications in crucial orbital surgeries. Clin. Anat. 29:998-1010, 2016. © 2016 Wiley Periodicals, Inc.

Osteologic analysis of ethnic differences in supernumerary ethmoidal foramina: implications for endoscopic sinus and orbit surgery

“…Our findings support previous studies that identified accessory foramina among heterogeneous ethnic groups at frequencies of between 28.5% and 47% . Further, the literature has shown accessory foramen in 37% of African‐American and 39.9% of Chinese skulls, which coincides with our findings.…”

“…However, recent anatomic studies have suggested that up to 6 branches can be present within a single orbit. A number of studies have described osteometric quantification of the ethmoid foramina as a surrogate for the number of actual ethmoidal arteries, with most studies analyzing heterogeneous ethnic cohorts. However, established ethnic differences in orbital morphology suggest that there may be concomitant significant differences in the presence and symmetry of supernumerary ethmoidal vessels across patient groups.…”

Sphenoidal artery: review of the literature and analysis of a dissected arterially injected fetal orbit

“…HC has been used [25,26]. It has also been named the cranioorbital foramen [9,36] meningo-orbital foramen [11,29,30], lacrimal foramen [17,21], and orbitomeningeal foramen [21,28]. HC and its other names are not listed in the 1998 Terminologia Anatomica [31].…”

The Anatomical Relationships of the Ocular Motor Nerves with an Emphasis on Surgical Anatomy of the Orbit

“…It is essential to know the microanatomy of the orbit and its neurovascular relations before undertaking any kind of surgery in this region. The surgical approaches directed to the orbit should be planned according to several characteristics, such as; the size, location, and anatomical relations of the related pathology and the least invasive possible technique which provides the greatest anatomical control should be chosen to decrease surgery related complications such as strabismus, ptosis, reflex losses, and weakness in eye movements (Maroon and Kennerdell, 1984; Rhoton, ; Abdel Aziz et al, ; Altay et al, ; Yoon and Pather, ).…”