Topography and morphometry of the infraorbital and mandibular foramen of the common sloth (Bradypus variegatus) for use in the application of perineural anaesthesia

A local anaesthetic block performed in cranial and mandibular foramina contributes towards analgesia and the reduction of systemic anaesthesia in procedures in the oral cavity. However, anatomical differences between in wild animals may require adaptations to the anaesthetic and surgical manoeuvres of the head used in domestic animals. With that in mind, we aimed to describe the topography and morphometry of the infraorbital and mandibular foramina in Bradypus variegatus, to support perineural anaesthetic approaches in the cranio-mandibular region of this species. We demonstrated that in B. variegatus there is no significant variability in the morphometric data, allowing access to the studied foramina to occur in a similar way in adult individuals. Finally, we understand that the techniques for the infraorbital and mandibular foramen needed to be adapted due to the anatomical singularities of the species, which culminated in new reference points for more assertive needle positioning.

Topography of the infraorbital foramen in human skulls originating from different time periods

BACKGROUND

The infraorbital foramen (IOF) is present on the maxilla under the infraorbital margin. Its identification is essential in various surgical procedures. The main aim of this study was the morphometric assessment of the position of the right and left infraorbital foramina in relation to specific structural elements of the facial skeleton, their width and direction, and also the determination of the location of these foramina above maxillary teeth in examined male skulls (belonging to European populations) dated to the beginning of the 20th century and the medieval and post-medieval period. This aim concerned also the assessment of the symmetry of the examined foramina (their location and size). An additional goal was to determine differences between the cranial samples concerning the analysed traits.

MATERIALS AND METHODS

The six metric and two non-metric traits concerning the IOF were collected from the male cranial samples including modern skulls (n = 87), the medieval and post-medieval skulls (from 13th centuries and 15-17th centuries, respectively; n = 47) obtained from archaeological excavations in Wroclaw, and the sample of the medieval skulls (11-13th centuries, n = 100) from Sypniewo. The sex and age of the specimens were determined using the standard methodology. The appropriate statistical analysis was performed.

RESULTS

Significant differences were established for three traits (taken from the left and right side) in the case of modern skulls (diameter of IOF, its distance to the midline, and zygomaticomaxillary suture) and one in the case of medieval skulls from Sypniewo (distance to the midline). In all of the cranial samples IOF most frequently occurred above the first upper molar. The greater diameter of IOF and its shorter distance to the alveolar crest and nasal notch were observed in non-modern skulls compared to modern skulls.

CONCLUSIONS

The results of this study provide new additional data on the topography of IOF and its asymmetry, confirm the presence of both geographical and chronological differences between populations, and can be used in dental practice, and forensic odontology in the analysis of archaeological bone materials.

Morphological and Morphometric Relations of Infraorbital Foramen in North Indian Population

Introduction The evidence regarding the anatomy of the infraorbital foramen in the Indian population is limited. It mainly focuses on its shape, size, and incidence in the Indian population. The current study aimed to evaluate morphometric parameters of infraorbital foramen that can help clinicians during surgery and procedures around it. Methods We evaluated 90 dry adult human hemi-skulls. The morphological parameters studied included the assessment of the shape of the infraorbital foramen, its horizontal and vertical diameters, and its relation to the teeth of the upper jaw. In addition, we measured the distance of the infraorbital foramen from the anterior nasal spine, nasion, infraorbital margin, and the lower extent of the alveolar margin. The length of the infraorbital canal till the inferior orbital fissure and the infraorbital groove and the infraorbital canal orientation angles in different planes were also measured. The measurement values were compared between the right and left side hemi-skulls. Results The oval-shaped infraorbital foramen was most commonly noticed. The mean vertical and transverse diameters were 3.8 mm and 2.6 mm, respectively, on the right side. The left side's mean vertical and transverse diameters were 3.9 mm and 2.5 mm, respectively. The most common location of infraorbital foramen was in line with the maxillary second premolar tooth. The distances of infraorbital foramen from the alveolar margin were 29.6 mm and 29 mm on the right and left sides, respectively. The distances of the infraorbital foramen from the anterior nasal spine were 34.3 mm and 34.2 mm on the right and left sides, respectively. The distances of infraorbital foramen from the nasion were 42.3 mm and 42.2 mm on the right and left sides, respectively. The distances of infraorbital foramen from the inferior orbital margin were 5.8 mm and 6.2 mm on the right and left sides, respectively. The distances between the inferior orbital margin and infraorbital groove were 12.7 mm and 12.7 mm on the right and left sides, respectively. The distances between the inferior orbital margin and inferior orbital fissure were 27.5 mm and 27.1 mm on the right and left sides, respectively. The orientation angles of infraorbital foramen were 48.31° in the horizontal plane, 34.07° in the Frankfurt plane, and 14.4° in the parasagittal plane. Conclusion Our findings suggest that the location of the infraorbital foramen is difficult to standardize, considering the wide interindividual variations in the foramen relations. Further research should be performed to investigate the parameters related to the distance and orientation of the infraorbital foramen in relation to nearby bony landmarks that are least affected by individual variations in skull morphology.

Investigating the relationship between infraorbital canal morphology and maxillary sinus size

The purpose of the current study was to investigate relationships between maxillary sinus (MS) dimensions and the bony structures associated with the infraorbital nerve (ION). Computed tomographic scans of 87 adult crania (174 sides) from four morphologically diverse groups (West Africans, East Africans, North Asians, Europeans) were utilized. Seven primary variables were collected: infraorbital canal (IOC) type; infraorbital foramen (IOF) shape; distance from the foramen rotundum to IOF (FR-IOF); distance from the posterior wall of the infraorbital groove to IOF (IOG-IOF); and MS length, breadth, and height. Chi-square analyses indicated a significant association between IOC-type and IOF-shape (Pearson chi-square = 12.710; p-value = .013), with the most common pattern being oval IOFs and Type-I IOCs (45.68% of the sample; 74/162 sides). Analysis of covariance indicated a significant effect of ancestry (F = 8.333; p < .001) and MS length (F = 15.406; p < .001) on IOG-IOF distance. Ordinal regression analyses indicated that MS length (Wald chi-square = 7.103; p = .008) also maintained a significant effect on IOC-type, while multinominal regression analyses indicated that none of the measured parameters had a significant effect on IOF-shape. These results have clinical implications: recognizing IOC-type and IOF-shape relative to the MS is important to avoid ION damage during medical procedures. Overall, this study found most individuals possess Type-I IOCs (housed in the maxillary sinus roof) and oval-shaped IOFs. Most aspects of the ION pathway, including IOC-type and IOF-shape, were not influenced by ancestry or sex. However, antero-posteriorly longer MSs tend to possess Type-III IOCs protruding into the sinus, which could lead to surgical complications.

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.

Clinical Criteria for Selective Exploration of Orbital Floor in Zygomaticomaxillary Complex Fractures

Purpose

Exposing the orbital floor requires a surgical procedure that has its own challenges. Despite the meticulous clinical examination followed by sophisticated imaging modalities, orbital floor defects associated with zygomaticomaxillary complex (ZMC) fractures may evade diagnosis and appropriate management. If surgeons can decide about the need for orbital floor exploration in patients with ZMC fracture, the chance of a postoperative eyelid deformity can be prevented. The aim of this article is to assess whether an association exists between the pattern of fracture line and the need for exploration of the orbital floor in ZMC fracture.

Materials and Methods

A retrospective study of 94 patients with isolated, unilateral ZMC fractures who were treated at our unit by open reduction of the ZMC complex with internal orbital exploration from January 2016 to January 2018. The records of all patients were reviewed and specific data related to fracture pattern and orbital floor defect were registered and assessed.

Results

Of the 94 cases with isolated, unilateral ZMC fractures, in 80 cases the fracture line propagated to the orbital floor, which required exploration but did not required any reconstruction and only the infraorbital rim was addressed; 14 of them required orbital floor reconstruction. Among the cases which required orbital floor reconstruction, the majority of the cases where those with fracture involving medial side of infraorbital foramen (n = 10) followed by lateral side (n = 3) and through the foramen (n = 0) and lastly bilateral side of the foramen (n = 1).

Conclusion

The present study highlights the pattern of fracture line at the level of infraorbital rim can predict the need for orbital floor exploration while treating ZMC fractures for purpose of orbital floor reconstruction. Based on the results and a review of the records, authors strongly recommend the need for exploration of orbital floor when the fracture line passes medial to the infraorbital foramen.

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.

Morphometric evaluation and surgical implications of the infraorbital groove, canal and foramen on cone-beam computed tomography and a review of literature

BACKGROUND

The purpose of this study is to evaluate the anatomy, morphometry, and variations of infraorbital groove (IOG), infraorbital canal (IOC) and infraorbital foramen (IOF) on the cone-beam computed tomography (CBCT) images and to investigate their relations with surrounding structures.

METHODS

IOG, IOC and IOF were evaluated retrospectively in CBCT images of 75 female (F) and 75 male (M) cases with a range of 18-65 years (F: 37.62 ± ± 13.55, M: 37.53 ± 15.87) by Planmeca Romexis programme. IOG, IOC and IOF were examined bilaterally (300 sides) in the cases. The 13 parameters were measured on these images in axial, sagittal and coronal planes.

RESULTS

There was a very weak positive correlation between the age and the angle between IOC and IOG (p = 0.015, r = 0.198), there was a weak positive correlation between the age and skin thickness (p = 0.001, r = 0.281), and there was no correlation between the age and other parameters. A total of 21 (7%) IOCs were detected in maxillary sinus, bilaterally in 6 cases and unilaterally in 9 cases (5 on the left, 4 on the right). In 1 case, bilaterally, IOC was separated 2 canals while running anteriorly in the maxillary sinus. The larger one was directed to IOF in its normal course and the smaller one was directed to lateral wall of nasal cavity and opened to the inferior nasal meatus in front of the opening of nasolacrimal duct.

CONCLUSIONS

We suggest that the parameters found in the present study may facilitate prediction of the location of the infraorbital nerve. Knowledge of this exact position in relation to easily measurable parameters may decrease the risk of infraorbital nerve injury during surgical approaches directed to this region and might serve as a guide during local anaesthetic interventions for dentistry, ophthalmology, plastic surgery, rhinology, neurosurgery and dermatology.

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.

Variations in emergence and course of the inferior palpebral nerve

Comprehensive understanding of the anatomy of the inferior palpebral (IP) nerve is crucial to preservation of sensation in the inferior eyelid and conjunctiva. Iatrogenic injuries may occur during blepharoplasty, repair of orbitozygomatic fracture and other maxillofacial surgeries involving this region. Although several studies depict the anatomical variations of the main infraorbital nerve (ION), little information exclusive to the IP nerve exists. This study provides information on the additional variations of the ION with reference to the IP nerve. The study was performed on 84 IP nerves by dissection of 42 formalin-fixed cadavers from the laboratory of topographic anatomy, Department of Human Anatomy, University of Nairobi, Kenya. Each of the nerves were exposed at the emergence and followed to their termination. Variations encountered involved emergence, course, and even absence. Variant emergence was through an accessory infraorbital foramen, an infraorbital notch, and as a common trunk with the external nasal nerve. This nerve shows high anatomical variability that may account for the difficulties and complications encountered in clinical interventions. It is believed that this information will improve clinical management of conditions affecting the region of distribution of the IP nerve.