Anatomical and Morphometric Analysis of Accessory Infraorbital Foramen

Location of infraorbital and accessory infraorbital foramina in Iranian population: a retrospective radiological study with crucial clinical implications

PURPOS

The location of infraorbital foramen (IOF) and the prevalence of accessory IOF vary among different populations. It may lead to infraorbital nerve (ION) blockage during surgery. This study aimed to assess the IOF location and AIOF frequency in Iranian people.

METHOD

In this retrospective cross-sectional study, 500 paranasal sinus computed tomography scans of adults were examined using the INFINITT PACS system.

RESULT

The distance from IOF to infraorbital margin (IOM), mid-pupillary line (MPL), midsagittal line (MSL), canine eminence (CE), and skin thickness (ST) was 8.97 ± 1.79, 5.73 ± 1.84, 24.86 ± 2.23, 20.39 ± 3.47, and 10.90 ± 2.59 mm, respectively. The vertical and transverse diameters of the foramen were 3.03 ± 0.65 and 3.71 ± 0.76 mm, respectively. In addition, the shape of 63.5% of the foramina was oval. The prevalence of AIOF was 9%, and its most common location was superomedial to IOF.

CONCLUSION

We believe that in this study, landmarks like IOM, MPL, MSL, CE and ST could help the clinicians localize IOF and improve the ION anesthesia success rate. Furthermore, the occurrence of AIOF should be considered by physicians to reduce the chance of injuries to the infraorbital neurovascular complex.

A morphological study and the variability in the number of infraorbital foramina in the African green monkey (Grivet) (Chlorocebus aethiops) using microcomputed tomography

Knowledge of the nonhuman primate morphology and anatomy related to craniofacial mechanoreception is essential for a fundamental understanding of the incidents that have occurred during the evolution of craniofacial features. The present study focuses on the variability in the number of infraorbital foramina and associated anatomical structures such as the infraorbital canal (IOC) and the infraorbital groove (IOG), as they are considered to play an important role in the behavioral ecology of these animals. A total of 19 skulls of Chlorocebus aethiops were analyzed. The number of infraorbital foramina was assessed macroscopically using a magnifying glass and a small diameter probe. Three dimensional (3D) projections and morphometric analysis of the infraorbital foramina, IOCs, and IOGs were performed using microcomputed tomography (micro-CT) for two skulls that represent one of the most common morphological types. Regardless of sex and body side, the most common morphological type observed in the studied species is the presence of three infraorbital foramina. The IOC takes a funnel or pinched shape. 3D projections were made to assess the course of the infraorbital vascular and nerve bundles in selected individuals. The results indicate a high morphological diversity within the species, although there appears to be a consistent distribution pattern of infraorbital neurovascular bundles in species of the Cercopithecidae family. The use of X-ray micro-CT allowed 3D visualization of the maxillary region to determine the variability of the infraorbital foramina and to track the division of the infraorbital neurovascular bundle in the case of the most common macroscopic expression of the number of the infraorbital foramen in C. aethiops, as well as the morphometric of the IOCs and IOGs which are related to mechanoreception of the primate's snout.

Evaluation of accessory mental foramen and accessory infraorbital foramen with cone-beam computed tomography in Turkish population

It was aimed to evaluate the frequency of accessory mental foramen (AMF) and accessory infraorbital foramen (AIOF) and analyse the correlation between these two foramina using cone-beam computed tomography (CBCT). The retrospective study reviewed the CBCT images of 1020 patients. The rates of AMF and AIOF were evaluated according to sex and age distributions. Correlations between the localizations of AMF and AIOF in the right and left jaws and the correlations between the occurrences of these foramina were evaluated. In the CBCT images of the 1020 patients, AMFs were detected in 48 patients, among which 14 were in the right half jaw, and 34 were in the left half jaw. AIOFs were detected in 143 patients, among which 65 were in the right half jaw, and 78 were in the left half jaw. Recognising and detecting AMF and AIOF with CBCT is important in terms of preventing complications that may occur in surgical procedures.

The relative locations of the supraorbital, infraorbital, and mental foramina: A cadaveric study

The purpose of this study is to investigate the applicability of the current surgical guideline stating that the main facial foramina that transmit cutaneous nerves to the face (supraorbital notch/foramen, infraorbital foramen, and mental foramen) are equidistant from the midline in European and Hispanic populations. Previous studies suggest this surgical guideline is not applicable for all ethnicities; however, to our knowledge, no data have been published regarding the accuracy of this guideline pertaining to the Hispanic population. An experimental study was performed on 67 cadavers donated to the Human Anatomy Program at UT Health San Antonio. The supraorbital, infraorbital, and mental foramina were dissected and midline structures including the crista galli, internasal suture, anterior nasal spine, and mandibular symphysis were identified. The distance from each foramen to midline was recorded using a digital caliper. For all cadavers/ethnicities studied, the supraorbital, infraorbital, and mental foramina were 25.32 mm, 29.57 mm, and 25.55 mm to the midline, respectively. Thus, the infraorbital foramen is located significantly more lateral compared to the supraorbital (p < 0.0001) and mental foramina (p < 0.0001). After dividing the sample based on ethnicity, this relationship was also true for the European sample and tended to be true for the Hispanic sample. Significant anatomical variations exist in the current surgical guideline stating that the supraorbital foramen, infraorbital foramen, and mental foramen are equidistant from the midline. Clinicians may need to adjust their methodology during surgical procedures of the face in order to optimize patient care.

Variability in the number of infraorbital foramina in rhesus macaques (Macaca mulatta) and cynomolgus macaques (Macaca fascicularis)

This study aimed to determine the number of infraorbital foramina in monkeys of the Papionini tribe. The authors performed a μCT analysis of the morphology of the infraorbital foramina. A total number of 52 simian skulls belonged to two macaque species: Macaca mulatta and Macaca fascicularis were used in the study. The number of infraorbital foramina was counted macroscopically and with the use of a magnifying glass. Next, the skull representing the most common morphological type was selected and scanned by micro-computed tomography (μCT). The Shapiro-Wilk normality test was used in the study. To compare the differences in the number of infraorbital foramen between species, sex and sides, the Mann-Whitney U test was applied. Three infraorbital foramina were present in most individuals from the test group. The Mann-Whitney test revealed no statistically significant difference between the number of foramina on the right- and left-hand side. Likewise, no statistically significant differences between the numbers of infraorbital foramina across sexes were observed. Volumetric reconstructions revealed the presence of separate infraorbital canals for each infraorbital foramen. Craniofacial innervation in macaques is formed by complex branching patterns of cranial nerves. Variability in the number of infraorbital foramina suggests a variable maxillary innervation pattern in these animals. Based on the analysis of volumetric projections, the presence of two labial branches and a single nasal branch of the infraorbital nerve is suggested. Detailed descriptions are supported by quantitative data and μCT evidence.

Location of the accessory infraorbital foramen with reference to external landmarks and its clinical implications

The aim of this study was to define the location of the accessory infraorbital foramen (AIOF) with reference to accessible external landmarks in order to facilitate orbital and oculoplastic surgical procedures in the maxillofacial region. Forty-four hemifaces from 25 cadavers were dissected. The lateral canthus, subnasal point, and lacrimal caruncle were used as anatomic reference points. The AIOF was observed in 8 of the 44 hemifaces (18.2%) and was situated at a mean distance of 7.2 mm superomedial to the IOF. The horizontal distance from the lacrimal caruncle to the AIOF was 0.3 mm. In all cases the AIOF was situated at a point that was no more than 8 mm from the intersection point of a vertical line passing through the lacrimal caruncle and an oblique line joining the lateral canthus and the subnasal point. Surgeons anesthetizing or performing surgical procedures in the maxillofacial region should be aware of the frequency of the AIOF (18.2%) and its location (on the superomedial side of the IOF). We propose that injecting at the intersection point of a vertical line passing through the lacrimal caruncle and an oblique line joining the lateral canthus and the subnasal point would successfully block the accessory branch of the infraorbital nerve. Likewise, surgeons operating in this region should be aware of the location of the AIOF in order to avoid inadvertent iatrogenic injury to a duplicated infraorbital nerve.

False and true accessory infraorbital foramina, and the infraorbital lamina cribriformis

The infraorbital nerve (ION) and artery (IOA) course in the infraorbital canal (IOC) to exit through the infraorbital foramen (IOF). Few previous studies brought evidence of accessory IOF. Evaluation of the IOF in Cone Beam Computed Tomography (CBCT) is more accurate to determine whether or not foramina of maxilla are supplied by canaliculi deriving from the IOC. We performed a retrospective anatomical study of the CBCT files of 200 patients. An accessory infraorbital foramen located inferior to the infraorbital margin (AIOF) was found in 18/200 right maxillae and in 13/200 left ones. Canaliculi deriving from the IOC supplied accessory foramina in the sutura notha- AIOF(SN) - in 15 maxillae. Noteworthy, the AIOF(SN)-negative maxillae displayed the SN and the vascular foramina of Macalister. In 94% of cases the AIOF were unique. A single maxilla (3%) had a double AIOF. In a different case (3%) were found three accessory infraorbital foraminules transforming the anterior wall of the antrum into a veritable lamina cribriformis infraorbitalis. A single prior study distinguished AIOF from AIOF(SN), while most of different other ones were performed on dry bones. Therefore, the reports of prevalence for the number and location of AIOF should be regarded with caution. Foramina of the SN could equally get intraosseous and extraosseous supply, this distinction being accurately made in CBCT.

Location of the infraorbital foramen with reference to soft tissue landmarks for regional nerve blocks during midface surgery

PURPOSE

An infraorbital nerve (ION) block is widely used to accomplish regional anesthesia during surgical procedures involving the midface region. This study aimed to elucidate the exact location of the infraorbital foramen (IOF) in relation to clinically useful soft-tissue landmarks for achieving an effective ION block.

METHODS

Forty-three hemifaces from 23 embalmed Korean cadavers were dissected. The lateral canthus, peak of Cupid's bow, medial limbus, and midline were used as reference points. The distances from the IOF to the midline and the lateral canthus were measured.

RESULTS

The IOF was located approximately 25 mm below the lateral canthus and 27 mm lateral to the midline. In all cases, the IOF was situated within 9.0 mm of the crossing point of the oblique line connecting the lateral canthus to the peak of Cupid's bow and the vertical line through the medial limbus.

CONCLUSION

Considering the spread of an anesthetic agent, injecting it into the crossing point of the oblique line through the lateral canthus to the peak of Cupid's bow and the vertical line through the medial limbus would successfully block the ION in most patients.

The Infraorbital Foramen in a Sample of the Lebanese Population: A Radiographic Study

Purpose

The infraorbital foramen (IOF) is an important structure in the maxillofacial region through which important structures pass. Wide variability in the shape and location of the infraorbital foramen among different populations and ethnic groups is present. So we conducted this study to specify the IOF shape, the presence of accessory foramina, and the IOF location with respect to anatomic landmarks in the Lebanese population.

Patients and method

A cross-sectional retrospective study was conducted on cone-beam computed tomography (CBCT) scans of 105 Lebanese adult patients. Images were reviewed and the shape, diameter, and location of the IOF were recorded. The presence of an accessory foramen was also noted. Then, SPSS version 21 (IBM Corp., Armonk, NY, US) was used for the statistical analysis.

Results

Concerning the distances from the IOF to the anatomic landmarks, the distance from the IOF to the infraorbital margin measured 7.98 ± 1.41 mm, to the lateral nasal wall 10.61 ± 2.39 mm, and to the midline 24.71 ± 2.09 mm. When distances were compared, a statistical difference was only identified in the distance between the IOF and the lateral nasal wall (p=0.00), and the distance between the IOF and the middle of the face (p=0.016) between genders. For the shape of the IOF, 54.8% of the IOF were circular in shape, and this shape was the most common shape in females. An accessory foramen was present in 8.6% of the cases. Finally, the mean diameter of the foramina measured 3.71 ± 0.63 mm.

Conclusion

The IOF shows a lot of variability between different populations. Thus, the exact location should always be remembered during an infraorbital nerve (ION) block, during maxillofacial surgeries, and during esthetic procedures involving the facial region in order to prevent unnecessary complications.

The Infraorbital Foramen Is Located Midway Between the Nasospinale and Jugale: Considerations for Infraorbital Nerve Block and Maxillofacial Surgery

Identification of the infraorbital foramen is important in infraorbital nerve block and the prevention of iatrogenic injury of the infraorbital nerve in maxillofacial surgeries. This study assessed the location of 887 infraorbital foramina from 518 adult crania of varied sex and population. The study assessed the midpoint of a line segment spanning from nasospinale to jugale (NS-J) relative to the infraorbital foramen. The mean distance of the NS-J midpoint from the infraorbital foramen was 2.1 ± 1.9 mm (mean ± SD) with a mode of 0 mm (266:887; 30%). The NS-J midpoint was located in the same plane or inferior to the infraorbital foramen in 98.4% of sides (873:887). There were no significant differences between sexes, populations, or sides with regard to the NS-J midpoint to infraorbital foramen distance. The NS-J midpoint can be used to locate the infraorbital foramen in both females and males of varied populations regardless of craniofacial diversity. The results of this study will aid in infraorbital nerve block procedures and maxillofacial surgery.

Location of the infraorbital foramen with reference to soft tissue landmarks

PURPOSE

The location of the infraorbital foramen and its variations are important during periorbital, dental, plastic, and oromaxillofacial surgeries. The aim of this study is to document the most practical anatomical soft tissue landmarks for defining the location of infraorbital foramen and infraorbital nerve for effective nerve blockade and to decrease its risk of injury during periorbital surgeries.

METHODS

Forty sides from 20 adult fixed cadavers were used for this study. The position of the infraorbital nerve was determined in reference to the lateral edge of the ala of the nose, medial and lateral palpebral commissures. All these three soft tissue landmarks were then connected to each other forming a triangular shaped region.

RESULTS

In 75 % of the cases the infraorbital foramen was located on the line which is connecting the lateral palpebral commissure to the ala of the nose. The closest distance of infraorbital foramen to the inferior orbital margin and to facial midline was also measured. The infraorbital foramen was located outside the previously defined triangular region in 20 % and inside the triangle in 5 %. The closest mean distance between the infraorbital foramen and the infraorbital margin was measured as 8.8 ± 1.0 mm and the distance between the medial wall of the infraorbital foramen and the facial midline was measured as 30.3 ± 2.7 mm.

CONCLUSION

The triangular region and the soft tissue landmarks we offered in this study may facilitate prediction of the locations of the infraorbital foramen thus, the infraorbital nerve.