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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., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Anatomical variations are a common feature of the human anatomy. Variation can explain some pathological conditions and is important to keep them in mind during surgical procedures. The relations between nerves and their adjacent arteries have been proposed to play a role in the generation of peripheral trigger migraines. Close opposition between nerves and arteries can lead to vascular compression of the nerve that triggers episodes of pain. We did a routine dissection of the infratemporal fossa and orbital floor by opening the maxillary sinus. Here we report a case where the infraorbital nerves form a nervous loop entrapping the infraorbital artery in the infraorbital channel. Similar cases of close nervous and arterial apposition are described for the auriculotemporal and occipital nerves. We think that accumulating knowledge of these rare variations could expand our understanding of rare conditions such as primary infraorbital neuralgia., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Purpose: This research aims to enhance understanding of the anatomy of the supraorbital nerve (SON) and greater occipital nerve (GON), focusing on their exit points, distal trajectories, and variability, utilizing a novel 3D representation., Methods: Ten cadaveric specimens underwent meticulous dissection, and 3D landmarks were registered. Models were generated from CT scans, and a custom 3D method was employed to visualize nerve trajectories. Measurements, including lengths and distances, were obtained for the SON and GON., Results: The SON exhibited varied exit points, with the lateral branches being the longest. The GON showed distinct branching patterns, which are described relative to various anatomical reference points and planes. No systematic left-right differences were observed for either nerve. 3D analysis revealed significant interindividual variability in nerve trajectories. The closest approximation between the SON and GON occurred between lateral branches., Conclusion: The study introduces a novel 3D methodology for analyzing the SON and GON, highlighting considerable anatomical variation. Understanding this variability is crucial for clinical applications and tools targeting the skull innervation. The findings serve as a valuable reference for future research, emphasizing the necessity for personalized approaches in innervation-related interventions., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Background: In orbital floor reconstruction, fractures involving the slope of the posterior end of the orbital floor make it difficult to determine the best location for implant placement. Therefore, landmarks for reconstruction are desirable to perform safe and reproducible reconstruction surgery., Methods: We developed a surgical procedure that focuses on three orbital landmarks: the infraorbital nerve, the inferior margin of the greater wing of the sphenoid bone, and the posterior superior wall of the maxilla., Conclusions: Landmark-based orbital floor fracture reconstruction enables accurate reconstruction of fractures that extend to the slope of the posterior end of the orbital floor., (© 2022. The Author(s).)

Purpose: The present study aimed to explore the glymphatic pathway in the intraorbital optic nerve (ON) using magnetic resonance imaging (MRI)., Methods: Following conventional MRI examination, a total of 89 outpatients underwent T2-weighted imaging in thin-sliced coronal and sagittal sections. Moreover, three injected cadaver heads were dissected., Results: In the cadaver specimens, differences in appearance between the central and peripheral parts of the ON were not observed. On the axial T2-weighted MRI performed in the initial examination, the central part of the intraorbital ONs was delineated as a well-demarcated, linear hyperintense area in 19% of patients. On the thin-sliced serial coronal images, the hyperintense areas were identified on both sides in 91% of patients. They were delineated as continuous hyperintense areas in the ONs with an inconsistent appearance even in the same nerve. In 12.4% of patients, the areas were divided into the upper and lower parts by a horizontal septum, while others showed variable morphologies, lacking a septum. On thin-sliced sagittal images, hyperintense areas were identified in 46% of patients., Conclusion: Hyperintense areas in the intraorbital ON detected on T2-weighted sequences may involve a glymphatic pathway with perivascular spaces of the ON and central retinal artery. These may be collapsed and difficult to identify on surgical and cadaver specimens., (© 2021. The Author(s), under exclusive licence to Springer-Verlag France SAS part of Springer Nature.)

In the last decade, a new surgical treatment modality was developed for frontal secondary headache, based on the assumption that the trigger of this pain entity is the entrapment of peripheral sensory nerves. The surgery entails a procedure, where an endoscopic approach is used to decompress the supraorbital and supratrochlear nerve branches, which are entrapped by the periosteum in the region of the corrugator supercilii muscle. Candidates for the surgery define their headache as moderate to severe persistent daily pressure or tension, localized in the frontal area, sometimes accompanied by symptoms of nausea and photophobia mimicking a primary headache-migraine. We created a step-by-step screening algorithm which is used to differentiate patients that have the highest chance for a successful surgical decompression. Up to now, published data regarding this type of surgery demonstrate long-lasting successful outcomes while adverse effects are minor. This article reviews and discusses from a surgeon's perspective decompression surgery for secondary headache attributed to supraorbital and supratrochlear nerve entrapment.

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.

Orbital floor fractures are one of the most commonly encountered maxillofacial fractures due to their weak anatomical structure. Restoration of the orbital floor following a traumatic injury or a tumor surgery is often difficult due to inadequate visibility and lack of knowledge on its anatomical details. The aim of this study is to investigate the locations of the inferior orbital fissure (IOF), infraorbital groove (G), and infraorbital foramen (Fo) and their relationship with the orbital floor using a software. Measurements from the inferior orbital rim (IOR) using the Fo, the IOF, G, and the optic canal (OC) were calculated in 268 orbits as reference points. The surgical landmarks from the G and the OC, the G and the IOF, the G and the intersection point were measured as 31.6 ± 6, 12.9 ± 4, and 12 ± 5 mm, respectively. The mean distances between the G and the IOR, the Fo and the IOF, and the Fo and the OC were found as 8.3 ± 2.1, 28.7 ± 3.5, and 53.6 ± 5.9 mm, respectively. The mean angles were calculated as OC-IOF-G 68.1° ± 16.4°; intersection-G-IOF as 61.4° ± 15.8°; IOF-OC-G as 19° ± 5.5°; OC-G-intersection as 31.5° ± 11.9°, G-intersection-OC as 129.5°, IOF-intersection-G as 50.5°. Furthermore, variable bony changes on the orbital floor which may lead to the differences at intersection point of the G and Fo were determined. In 28 specimens (20.9 %), unilateral accessory Fo (AcFo) was present. In 27 specimens, AcFo was situated supermaedially (96.4 %) on the main aperture. In one specimen, two intraorbital canals and Fo emerged from different points and coursed into different apertures. The measured mean distances of the AcFo-IOR and the AcFo-Fo were as 7 ± 2 and 7.3 ± 3.2 mm, respectively. The primary principle in the oculoplastic treatment of orbital floor reconstructions must be repositioning the herniated orbital aperture by maintaining the infraorbital artery and the nerve in the orbital floor. The IOF and the G were recommended as the more reliable oculoplastic surgical landmarks for identifying the orbital floor. To avoid pinching of the orbital floor structures, the triangle (IS-G-IOF) should be equilateral with an exigence of a 70° angle within it. Among each distance of the intersection-IOF, IOF-G, G-intersection should be equal. With the help of certain software, this study made possible to investigate the variability of the orbital floor structures, observe the variety in measurements and calculate the parameters which are crucial in implementing personalized reconstruction and implanting support.

This study reports the first case of abducens nerve duplication along its entire intracranial course, ending within the orbit. A distinct abducens nerve duplication reaching the common tendinous ring (annulus of Zinn), as well as another split within the intraconal segment of the nerve have been revealed. Additionally, two groups (superior and inferior) of abducens nerve sub-branches to the lateral rectus muscle were visualised using Sihler's stain. The analysed anatomical variation has never been reported before and it seems to be in the middle of the spectrum between the cases of duplication occurring only within the intracranial segments of the abducens nerve found in the literature and those continuing throughout the whole course of the nerve. Abducens nerve duplication may be treated as a relic of early stages of ontogenesis. Such a variant might result from alternative developmental pathways in which axons of the abducens nerve, specific for a given segment of the lateral rectus muscle, run separately at some stage, instead of forming a single stem.

This case reports a bilateral asymmetrical posterior extension of the frontal sinuses into the orbital roof with an unusual expansion into the roof of the optic canal in a 55-year-old male cadaver. The posterior extensions of the sinus were lined by mucoperiosteum and were separated from the underlying orbital contents and optic nerve by a thin plate of bone. This knowledge of an unusual anatomic variation of the frontal sinus may help understand better the ocular and intracranial complications associated with frontal sinus pathologies.

The infraorbital canal (IOC) normally courses above the maxillary sinus in the orbit floor. During a retrospective study of cone beam computed tomography (CBCT) scans, we found a previously unknown variant of the IOC. The IOCs were absent, being replaced by lateroantral canals coursing around and not above the maxillary sinus to open at infraorbital foramina which were located above the second upper premolar teeth. On coronal multiplanar reconstructions, the lateroantral canals were located anatomically at the outer limit of the zygomatic recess of each maxillary sinus, while the upper wall of the sinus was devoid of any canal. Such rare variant should be kept in mind by dental practitioners and surgeons, as it can determine modifications of common procedures. In this regard, the anatomy of maxilla, as well as mandible, should be evaluated in CBCT on a case-by-case basis.

This study was designed to provide anatomic data to help surgeons avoid damage to the ocular motor nerves during intraorbital operations. The microsurgical anatomy of the ocular motor nerves was studied in 50 adult cadaveric heads (100 orbits). Dissections were performed with a microscope. The nerves were exposed and the neural and muscular relationships of each portion of the nerve were examined and measured. The superior division of the oculomotor nerve coursed between the optic nerve and the superior rectus muscle after it left the annular tendon, and its branches entered into the superior rectus muscle and levator muscle. A mean of five fibers (range 3-7) innervated the superior rectus muscle, and a mean of one fiber (range 1-2) followed a medial direction (84%) or went straight through the superior rectus muscle (16%). The inferior division of the oculomotor nerve branched into the medial rectus, inferior rectus and inferior oblique muscles. The trochlear nerve ended on the orbital side of the posterior one-third of the superior oblique muscle in 76 specimens. The abducens nerve ended on the posterior one-third of the lateral rectus muscle in 86 specimens. If the belly of the lateral rectus muscle was divided into three superior-inferior parts, the nerve commonly entered into the middle one-third in 74 specimens. Based on the observed data, microanatomical relationships of the orbital contents were revised.

The infraorbital nerve (ION) supplies the skin and mucous membranes of the middle portion of the face. This nerve is vulnerable to injury during surgical procedures of mid-face. Severe pain and loss of sense are noted in patients whose infraorbital nerve is either entirely or partially lost after these surgeries. We investigated the distribution area and topography of the ION, about which little is currently known, by dissecting 43 hemifaces of Korean cadavers. The ION produced four main branches, the inferior palpebral, internal nasal, external nasal, and superior labial branches. The inferior palpebral branch was generally bifurcated, giving off a medial and a lateral branch (58.1%). The internal nasal branch ran superior to the depressor septi muscle, along the ala of the nose. It supplied the skin of the philtrum and gave off a terminal branch that supplied the nasal septum and the vestibule of the nose. The external nasal branch was distributed diversely supplying areas between the root and the ala of the nose. The superior labial branch was the largest branch of the ION produced the most subbranches. These subbranches were divided into the medial and lateral branches depending upon the area that they supplied.

Although variations of the anterior part of the cerebral arterial circle of Willis are quite well known, though some anomalies are exceedingly rare. In a 61-year-old female individual, on both sides the precommunicating parts of the anterior cerebral artery were found to course inferiorly to the ipsilateral optic nerves. This anomaly was associated with an agenesis of a left posterior communicating artery. The anatomic features, the possible high prevalence of associated aneurysms of the anterior communicating artery complex as well as implications for surgical planning or endovascular treatment are outlined and embryologic considerations and discussed.

A study was carried out in twenty human fetuses on the relationships of the orbital muscle of Müller. This muscle forms a lamina of smooth muscle fibres that cover the inferior orbital fissure. The latter is very wide during the fetal period because ossification of the bones that delimit this region is still incomplete. Some fibres of the orbital muscle extend along the superior orbital fissure under the inferior ophthalmic vein and the lower wall or floor of the cavernous sinus. This association suggests a possible influence on autonomically mediated vascular dynamics.

This investigation was designed to extend our present knowledge of the supraorbital n. (SO n.) distal to the supraorbital notch. It is based on 40 dissected hemi-faces and the position of the notch and the periosteal and frontalis cutaneous branches of the SO n. were studied. The notch was 33.05 mm from the midline on the right side and 30.70 mm on the left. The periosteal branch arises from the lateral frontalis cutaneous branch. Its ascends in an oblique direction laterally and ends in two terminal branches. The frontalis cutaneous branch, after a very short trunk, divides into two branches, medial and lateral. The medial or deep branch enters the corrugator supercilii m. between its fibers. Most frequently, it passes under the inferior fasciculus and superficial to the middle and superior ones. Leaving the corrugator m., it ascends medially into the frontalis m., supplying the median cutaneous frontalis region. The lateral or superficial branch crosses superficial to the corrugator supercilii m. to penetrate the frontalis m. in an ascending and lateral direction, supplying the lateral frontalis region. The two branches enter the frontalis m., displaying a zigzag pattern in order to adapt its length during expressive movements. They cross the frontalis region together with the SO a. and two veins supplying the nerve and the frontalis m. These anatomic data may explain some of the complications after surgery for ptosis and blepharospasm.

This work is based on the microscopic study of 30 trochlear nerve trunks (15 heads). In 17 cases, the trunk arose from two nerve bundles, in 8 cases from one bundle, and for the other 5 nerves, three or four bundles. The mean total length of the trochlear nerve was 86 mm. The nerve may be separated into the 3 following parts: infratentorial, intracavernous, intraorbital. In all 30 cases studied, the first part of the nerve was infratentorial, thus leading us to suggest the term "infratentorial part" for this segment of the nerve. In 27 cases, contact was found with the superior cerebellar artery, in the infratentorial part. In the intracavernous part of ten nerves we found two rami tentorii and in eight cases fibers were exchanged with the ophthalmic nerve. In the orbit, 18 trochlear nerves crossed the posterior ethmoidal artery. 23 trochlear nerves ended on the medial face of the superior oblique muscle. The remaining 7 ended at the superior border of the muscle.