Anatomical study of the infraorbital foramen

Abstract

Detailed knowledge of variations of the infraorbital foramen (IOF) and the establishment of a constant reference point for needle insertion are important for safe and successful regional block and for avoiding iatrogenic injury to the nerve during surgery in the midfacial region. Infraorbital foramina from 133 sides of 67 dry intact adult skulls of undetermined gender were examined for variations in shape, number, location in relation to bony landmarks, and relationship to the maxillary teeth. The angles of needle insertion in the sagittal and Frankfurt planes were determined. The infraorbital foramina were located at an average distance of 6.33 ± 1.39 mm below the infraorbital margin, 25.69 ± 2.37 mm from the median plane, 15.19 ± 1.70 mm from the lateral margin of the piriform aperture, and 28.41 ± 2.82 mm above the maxillary alveolar border. The average angles of needle insertion through the IOF with the sagittal and Frankfurt planes were 21.14° ± 10.10° and 31.79° ± 7.68°, respectively. Multiple foramina were found in 21% of the hemi-skulls. The foramen was less than 2 mm in size in 23.31% of the hemi-skulls. The position of the IOF with respect to the maxillary teeth varied from the interval between the canine and first premolar to the first molar, but in half of the specimens it lay in line with the second maxillary premolar tooth. The observations made in this study should be useful for planning infraorbital nerve block or surgery around the IOF.

Morphometric Characteristics of the Infraorbital Foramen on Volume-Rendered Ct Scans

“…The IOM is one of the most commonly used reference points. There was a wide range of values for the position of the IOF in relation to the IOM of the orbit, from 4 mm to over 10 mm [7][8][9], [11][12]. Our results were comparatively similar to that found in previous studies.…”

“…Knowing the relative distance of the IOF from other anatomical landmarks may help in defining the position of the infraorbital neurovascular bundle. In the previous study, the mean distances IOF-FML were reported as 26.45, 26.95, 28.5, 25.26, and 25.69 mm [6,8,10,11,12]. Our results showed that the mean distances IOF-FML were 26.35 ± 1.84 mm and 25.98 ± 1.53 mm in the right and left side, and 26.43 ± 1.79 mm and 25.86 ± 1.55 mm in male and female, respectively.…”

“…Various anatomical studies have been conducted with the aim to describe anatomical variations of the exit point of the infraorbital nerve and vessels from the orbit [6][7][8][9][10][11][12][13]. For a number of years, the research on the morphometry of the IOF has been realized on cadaveric or dry skulls.…”

“…The first one involves experimental procedures carried out on cadaveric and dry skulls [3][4][5][6][7][8][9][10][11][12]. The second one involves the evaluation of cranial structures by MDCT [13].…”

“…Existing data concerning variations of the foramina related to the gender and side are still conflicting. Furthermore, large variations in measurements have been reported in the literature with regard to the distance between the IOF and other reference points on the face [6][7][8][9][10][11][12].…”