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The canalis sinuosus, a canal containing the anterior superior alveolar nerve bundle, originates from the infraorbital canal and extends along the maxillary sinus and nasal cavity edges to the anterior maxilla. It was once regarded as an anatomical variation. However, with the widespread application of cone beam computed tomography (CBCT), the detection rate of canalis sinuosus in the population has increased. The canalis sinuosus exhibits diverse courses, branching into multiple accessory canals and terminating at the nasal floor or the anterior tooth region, with the majority traversing the palatal side of the central incisor. The anterior superior alveolar nerve bundle within the canalis sinuosus not only innervates and nourishes the maxillary anterior teeth and the corresponding soft tissues, and the maxillary sinus mucosa, but also relates to the nasal septum, lateral nasal wall, and parts of the palatal mucosa. To minimize surgical complications, strategies for preventing and treating canalis sinuosus injuries need to be investigated. Preoperatively, CBCT is used to identify the canalis sinuosus and to virtually design implant placement at a distance of more than 2 mm from the canalis sinuosus. Intraoperatively, assessing bleeding and patient comfort, complemented by precision surgical techniques such as the use of implant surgical guide plates. Postoperatively, CBCT is used to examine the relationship between the implant and the canalis sinuosus, and treatment of canalis sinuosus injuries can be tailored based on the patient's symptoms. This review summarizes the detection of canalis sinuosus in the population, its anatomical characteristics, and the physiological functions in the anterior maxilla, and discusses strategies for avoiding canalis sinuosus injuries during implant surgery, thereby enhancing clinical awareness and providing references for clinical decision-making.

The canalis sinuosus is an anatomical variation whereby the infraorbital canal sometimes generates a small, lateral branch (canal) close to its midpoint, to allow the passage of the anterior superior alveolar neurovascular bundle in the anterior maxilla. This article focuses on an incidental finding of this variant, in a 74-year-old Trinidadian female of Afro-Caribbean descent with an endodontic presenting complaint. The canalis sinuosus shadow on conventional radiography resulted in uncertainty as to the offending tooth until a 3-dimensional scan was undertaken in this region. This report will discuss the implications of the presence of this canal from radiologic, endodontic, and surgical perspectives., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: To develop and evaluate a transorbital endoscopic approach to the foramen rotundum to excise the maxillary nerve and infraorbital nerve branch., Methods: Cadaveric dissection study of 10 cadaver heads (20 orbits). This technique is predicated upon 1) an inferior orbital fissure release to facilitate access to the orbital apex and 2) the removal of the posterior maxillary wall to enter the pterygopalatine fossa (PPF). Angulations along the infraorbital nerve were quantified as follows: the first angulation was measured between the orbitomaxillary segment within the orbital floor and the pterygopalatine segment suspended within the PPF, while the second angulation was taken between the pterygopalatine segment and maxillary nerve as it exited the foramen rotundum. With refinement of the technique, the minimum amount of posterior maxillary wall removal was quantified in the final 5 cadaver heads (10 orbits)., Results: The mean distance from the inferior orbital rim to the foramen rotundum was 45.55 ± 3.24 mm. The first angulation of the infraorbital nerve was 133.10 ± 16.28 degrees, and the second angulation was 124.95 ± 18.01 degrees. The minimum posterior maxillary wall removal to reach the PPF was 11.10 ± 2.56 mm (vertical) and 11.10 ± 2.08 mm (horizontal)., Conclusions: The transorbital endoscopic approach to an en bloc resection of the infraorbital nerve branch up to its maxillary nerve origin provides a pathway to the PPF. This is relevant for nerve stripping in the context of perineural spread. Other applications include access to the superior portion of the PPF in selective biopsy cases or in concurrent orbital pathology., Competing Interests: The authors have no financial or conflicts of interest to disclose., (Copyright © 2024 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Experimental maxillofacial surgery is commonly performed in pigs; however, locoregional anesthesia of this area has not been described. This study evaluated the feasibility of a novel maxillary nerve block approach. In part I, cadavers were used to determine anatomic landmarks and assess maxillary nerve dye staining by using 0.03 mL kg -1 of a 1:10 mixture of commercial food dye and 0.5% bupivacaine. In part II, 10 additional pig cadavers underwent bilateral ultrasound-guided maxillary nerve blocks by using trans-infraorbital canal needle placement. The maxillary nerve was harvested and scored based on degree of staining (0 and 1, absent or incomplete staining; 2, staining; >1 cm circumferentially). Intracranial and intraconal spread of dye was evaluated. A Kruskal-Wallis test was used to compare infraorbital canal length estimated either externally via landmarks, internally via ultrasound, or actually measured after dissection. In 18 of 20 (90%) injections, successful staining (score = 2) of maxillary nerves was obtained for a nerve length of 2.4 ± 0.3 cm. Two of 20 cases (10%) had inadequate staining (score <2). At dissection of these 2 cases, the needle tip was observed to have collided with an unerupted tooth (third molar). No intracranial or intraconal spread of dye was observed. We detected no statistical differences between the estimated external, estimated internal, or actual dissection methods for measurement of infraorbital canal length ( P = 0.3). Ultrasound-guided trans-infraorbital maxillary nerve block in pigs is a feasible technique, warranting further work to evaluate its in vivo efficacy and safety.

Objective: To investigate and describe an extraoral approach to perform a maxillary nerve block in guinea pigs., Study Design: Prospective, randomized, blinded, descriptive, cadaveric study., Animals: A total of 14 adult guinea pig cadavers., Methods: Two cadavers were used for anatomic dissection and determination of maxillary nerve block approach. A maxillary nerve block via infraorbital approach was then performed in 12 cadavers. A low volume (0.1 mL) or high volume (0.2 mL) of diluted methylene blue injectate was randomly assigned to the right or left side, with the other volume used for the contralateral side. The maxillary nerve was dissected after each injection by an investigator blinded to injectate volume. The region of dye distribution was identified, and the degree of staining assigned an accuracy score (0-2). Nerve coverage was considered adequate if ≥6 mm of circumferential staining was present., Results: Accuracy evaluation indicated successful dye deposition in 10/12 [2 (0-2), median (range)] injections in the low volume group and 8/12 [2 (1-2)] injections in the high volume group. The majority (79.2%) of injections resulted in adequate nerve staining. There were no statistically significant differences between injectate volumes for accuracy (p = 0.64) or adequacy (p > 0.99) of staining., Conclusions: The infraorbital approach is a simple and practical method for maxillary nerve blockade in guinea pigs. An injectate volume of 0.1 mL results in adequate maxillary nerve coverage; however, additional studies are needed to assess the efficacy in clinical use., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To establish a new method for fast exposure of the internal maxillary artery (IMA) during extracranial-intracranial bypass surgery., Methods: To explore the positional relationship between the IMA and the maxillary nerve and pterygomaxillary fissure, 11 formalin-fixed cadaveric specimens were dissected. Three bone windows of the middle fossa were created for further analysis. Then the IMA length that could be pulled up above the middle fossa was measured after different degrees of removal of bony structure. The IMA branches under each bone window were also explored in detail., Results: The top of the pterygomaxillary fissure was located 11.50 mm anterolateral to the foramen rotundum. The IMA could be identified just inferior to the infratemporal segment maxillary nerve in all specimens. After drilling of the first bone window, the IMA length that could be pulled above the middle fossa bone was 6.85 mm. After drilling of the second bone window and further mobilization, the IMA length that could be harvested was significantly longer (9.04 mm vs. 6.85 mm; P < 0.001). Removal of the third bone window did not significantly improve the IMA length that could be harvested., Conclusions: The maxillary nerve could be used as a reliable landmark for the exposure of the IMA in the pterygopalatine fossa. With our technique, the IMA could be easily exposed and sufficiently dissected without zygomatic osteotomy and extensive middle fossa floor removal., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The infraorbital canal serves as a conduit for the infraorbital nerve. The canal travels anteriorly beneath the globe where it emerges onto the face at the infraorbital foramen. Variations in the morphology of the infraorbital canal have been reported and classified based on their relationship with the maxillary sinus. Similarly to the other orbital fat compartments, fat in the infraorbital canal serves as protection to the structures it surrounds. Generally, the orbital fat compartments do not undergo hypertrophy without a pathological etiology, therefore, it has been hypothesized that herniations of orbital fat are a result of age-related bony changes in the orbit. The inferior orbital rim, in particular, acts to support structures of the orbit including the fat compartments, ligaments, and muscles. The most commonly reported herniations are those of the infraorbital fat pads, which either prolapse into the inferior orbital fissure or move anteriorly to give patients the appearance of a bulging lower eyelid. Additionally, there are reports of traumatic injuries that result in herniation of the buccal fat pad into the maxillary sinus. Herein, we report a rare case of a herniation of the infraorbital canal fat into the maxillary sinus and review the salient literature.

Objectives: The maxillary nerve courses very close to the globe, rendering cats - with their large eyes - at risk of globe penetration during infraorbital or maxillary nerve blocks. Therefore, the goals of the study were to compare the distribution and potential complications of three infraorbital or maxillary regional injection techniques., Methods: Twenty-three bilateral maxillae of cat cadavers were used in a randomised blinded trial. Each maxilla was injected with a 0.2 ml 1:1 mixture of lidocaine 2% and a contrast medium by one of three injection techniques: infraorbital foramen (IOF; n = 14); infraorbital canal (IOC; n = 16); or maxillary foramen (MF; transpalpebral approach; n = 16) using a 25 G 1.6 cm needle. CT imaging of each cadaver head was performed before and after injections. A radiologist scored injectate distribution (none [0], mild [1], moderate [2], large [3]) in four locations: rostral, central and caudal IOC, and at the MF, for which the distribution side was also determined. Comparisons were performed with ordinal logistic mixed effects ( P <0.05)., Results: The median (range) total distribution score of the IOC and MF technique were significantly higher compared with the IOF technique (6.5 [4-12], 4 [2-8] and 0 [0-10], respectively). The total IOC score was also significantly higher compared with the MF technique. Injectate distribution at the MF was significantly more central following IOC injection compared with MF injection, which distributed centrolaterally. None of the techniques resulted in intraocular injection., Conclusions and Relevance: The IOC and MF techniques produced a satisfactory spread of the mixture that could result in effective maxillary anaesthesia in cats. Further studies are required to determine the effectiveness and safety of these techniques.

Background: The posterior auricular nerve (PAN) is an inspiring candidate for the additional axonal source in long-term facial paralysis to improve the functional results of the cross-facial nerve (FN) graft technique. However, no studies have analyzed the PAN's axonal load and its microscopic anatomy to assess its utilization in facial reanimation. The present study aims to examine the anatomical and microscopic features of the PAN to analyze its feasibility as a donor nerve., Methods: The bilateral facial side of 14 fresh frozen adult human cadavers was examined for the study. The PAN's anatomical course was recorded, and nerve specimens from the PAN and zygomatic nerve (ZN) were obtained to compare their microscopic anatomy and axon counts using a light microscope and transmission electron microscope., Results: The PAN's average branching distance and its course length were 5.8 ± 2.69 mm and 59.2 ± 5.85, respectively. The mean number of myelinated axons was 600.28 ± 69.97 in the PAN and 728.85 ± 166.31 in the ZN. This difference between the two nerves was statistically significant (p = 0.002). However, considering the gender variable, the mean axon counts of PAN and ZN were statistically similar for face sides and their average. Furthermore, the ultrastructural anatomy of both nerves was similar in electron microscopic evaluation., Conclusions: The present study confirms that the PAN is a proper candidate to be a supportive donor nerve due to its isolated site, consistent anatomical course, convenient ultrastructural anatomy as well as axonal load., Competing Interests: Declaration of Competing Interest Authors have no conflict of interest, financial or otherwise. There is no financial relationship with any institution, organization, or company., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Purpose: The importance of the infraorbital canal in the growth of the maxilla and associated mid-facial region has significance for innervation of this region as well as the associated dentition, yet little is known about the development of the canal. An analysis of its dimensions and morphology during the late prenatal and early postnatal periods was thus undertaken. The aim of this study was to describe changes in the morphology, size and branching pattern of the infraorbital canal during the late prenatal and early postnatal stages of human growth., Methods: Fifty human fetal and neonatal maxillae were analyzed. The sample included 27 late prenatal individuals (30 gestational weeks and birth) and 23 early postnatal individuals (birth and 1 year). Maxillae were scanned using a Nikon XTH 225 L micro-CT unit and analyzed using VG studiomax v3.2. Measurements included the maximum width, height and surface area of each foramen associated with the infraorbital canal and the total length of the canal, bilaterally., Results: All the measurements of the canal were greater in the early postnatal group than in the late prenatal group, while the walls and branching pattern of the canal were better developed in the postnatal group. Bone development occurred within the walls as development proceeded. Variations in the branching pattern of the canal were found., Conclusion: The morphology of the infraorbital canal reflected the developmental stage of associated structures such as the dentition, maxillary sinus and orbit.

​PURPOSE: Suprazygomatic maxillary nerve blocks (SMB) are used in adult and pediatric patients to provide analgesia for midface surgery and chronic maxillofacial pain syndromes. The ultrasound-guided SMB technique ensures visualisation of the needle tip, avoidance of the maxillary artery and confirmation of local anesthetic spread. The goal of this study was to correctly identify SMB sonoanatomical landmarks to ensure the nerve block is performed safely and effectively., Methods: Following an ultrasound-guided SMB with dye injection on 2 embalmed cadavers, pre-tragal face-lift style incision with a full thickness flap dissection was performed allowing accurate visualization of the bony landmarks being used for sonography and identification of the location of the injected dye., Results: This study identifies the correct sonoanatomic landmarks as the maxilla and the coronoid process of the mandible which suggests that the block needle tip and local anesthetic injection are within the infratemporal fossa as opposed to the previously reported pterygopalatine fossa., Conclusion: An improved understanding of the sonoanatomy will aid clinicians who are learning, performing and teaching the ultrasound-guided suprazygomatic approach to the maxillary nerve block.

The anatomical variations of the maxillary sinus septa, greater palatine artery, and posterior superior alveolar arteries might cause unexpected complications when they are damaged. Dentists who know these structures well might hope to learn more practical knowledge to avoid and assess injury preoperatively. Therefore, this review paper aimed to review the reported anatomy and variations of the maxillary sinus septa, greater palatine artery/nerve, and posterior superior alveolar artery, and to discuss what has to be assessed preoperatively to avoid iatrogenic injury. To assess the risk of injury of surgically significant anatomical structures in the maxillary sinus and hard palate, the operator should have preoperative three-dimensional images in their mind based on anatomical knowledge and palpation. Additionally, knowledge of the average measurement results from previous studies is important.

Purpose: Anatomical knowledge of the zygomatic region is important, because the zygomatic nerve and its branches may suffer lesions during surgical procedures in the periorbital region. The position and frequency of zygomaticofacial foramina (ZFF) may vary between individuals, and between one side and the other in the same individual. In the present study, we analysed the presence and location of ZFF, as well as the distance between them and the orbital cavity, in macerated skulls of adult individuals., Methods: We examined 287 macerated skulls, of individuals of both sexes, analysing the frequency and location of ZFF and the distance from the ZFF to the margin of the orbital cavity (OC)., Results: Zygomaticofacial foramina are very frequent structures which tend to appear singly. They are generally located in the temporal process of the zygomatic bone, but in many cases, they may be located in the mid portion of the bone. They also tend to appear at the same distance from the OC when left and right sides are compared. Sex was an important factor in determining differences in ZFF; the distance from the ZFF to the margin of the OC was greater in males than in females. Sex, age, side and skin colour did not affect the frequency and location of the ZFF., Conclusion: We consider that the mid portion of the zygomatic bone is the safest place to anchor zygomatic implants (ZI), since ZFF are less frequently located there than in the temporal process of the zygomatic bone.

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., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Purpose: Although a maxillary nerve (MN) block reportedly provides satisfactory analgesia for midface surgery and chronic maxillofacial pain syndromes, a safe and reliable MN block technique has not been reported. The goal of this anatomical study was to quantify the various angles and depth of the block needle, as well as to evaluate the impact of volume on the extent of injectate spread that might influence anesthetic coverage and block-related complications., Methods: Following an ultrasound-guided suprazygomatic MN block with dye injection, a dissection was performed in the pterygopalatine fossa (PPF) of four lightly embalmed cadaveric specimens. Half of the specimens were injected with 5 mL of dye, and the other half with 1 mL of dye. The needle depth was measured from the ultrasound images and using rubber markers. Following injection, dissection was performed to map the area of dye spread., Results: The median [interquartile range (IQR)] distance from the skin to the PPF was 37 [36-43] mm and 47 [40-50] mm by ultrasound and rubber marker methods, respectively. The median [IQR] needle orientation was 14 [11-32] degrees inferiorly and 15 [10-17] degrees posteriorly. The PPF was consistently dyed in the 5 mL group, but sporadically dyed in the 1 mL group. In the 5 mL group, spread outside of the PPF was seen., Conclusions: We showed that 5 mL of injectate far exceeds the capacity of the PPF, leading to drug spread outside of the PPF. Moreover, we found that 1 mL of injectate largely covered the nerve, suggesting a more efficacious and safer block procedure. This finding will need confirmation in future clinical studies.

Background: Lesions located at the petrous apex, cavernous sinus, clivus, medial aspect of the jugular foramen, or condylar regions are still difficult to fully expose using the operating microscope. Although approaches to this region through the middle cranial fossa have been previously described, these approaches afford only limited visualization. We have confirmed a transcranial infratemporal fossa combined microsurgical and endoscopic access to the petrous apex, clivus, medial aspect of the jugular foramen, and occipital condyle. We have presented the results of a micro-anatomical cadaver dissection study and its clinical application., Methods: Ten latex-injected cadaveric specimens (20 twenty sides) underwent dissection with navigational guidance to achieve an extended anterior petrosal approach combined with a far vidian corridor approach (between the foramen rotundum and foramen ovale). We performed anatomical dissections to confirm the surgical anatomy and the feasibility and limitations of this approach. Anatomical dissections were performed in the skull base laboratory of Lariboisière Hospital and Duke University Medical Center. This approach was then applied to some clinical cases., Results: The combination of the microscope and endoscope, aided by surgical navigation, was extremely effective and provided a wide view of the petrous rhomboid, the entire clivus, and the medial condylar regions. The extended extradural anterior petrosal approach provided a large corridor to petrous and clival lesions. Endoscopic assistance allows for wide and deep exposure of the middle to lower clivus, epipharyngeal space, and bilateral condylar regions. This approach successfully provided adequate surgical access for resection of tumors located in these regions. The depth of the medial aspect of the jugular foramen was 16.3 ± 1.2 mm deep from the geniculate ganglion. The emerging point of the inferior petrosal sinus in the jugular foramen was 16.5 ± 1.8 mm deep from the geniculate ganglion. The hypoglossal canal was 21.6 ± 2.2 mm deep from the geniculate ganglion. The foramen magnum was located 31.5 ± 2.4 mm deep from the gasserian ganglion. The inferior petrosal sinus was found to be a reliable landmark to identify the medial portion of the jugular bulb. The introduction of the endoscope through the middle fossa rhomboid enabled visualization of the medial aspect of the jugular bulb, which otherwise would be hampered by the internal auditory canal under the microscope., Conclusion: After microscopic exposure of the middle fossa rhomboid, neuronavigational endoscopic assistance facilitated visualization of the ventral cavernous region, petrous apex, retropharyngeal space, and middle and inferior clivus down to the medial aspect of the jugular bulb and condyle regions. Additional maxillary nerve-mandibular nerve vidian corridor visualization provides a lateral transsphenoidal approach to upper clivus lesions., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The accessory infraorbital foramen (AIOF) is an anatomical variation associated with the infraorbital foramen (IOF) and nerve (ION). Its occurrence and neural contents have clinical implications regarding failure of loco-regional anesthesia and risk of neural damage during surgical interventions involving the maxillary region. Thus, morphologic characterization of the AIOF and neural contents as well as the spatial relationships to the IOF are potentially useful for optimizing surgical procedures. Additionally, predictive features of the AIOF based on its relationship to IOF morphology could enable the surgeon to anticipate its presence and proceed accordingly. The purpose of this study was to determine whether the presence of an AIOF and its neural contents affected the size, shape, and composition of the IOF and ION. The specific hypothesis tested was that the topography and fascicular composition of the ION and IOF differs between individuals possessing an AIOF and those lacking this anatomical variant., Methods: Gross topographic features of the IOF (42 crania) were compared between specimens possessing (test) or lacking (control) an AIOF. Nerve fascicles of ION (60 cadaveric sides) were examined histologically and compared morphometrically between specimens presenting or lacking an AIOF. An additional sample of 30 crania was subjected to cone-beam computed tomography (CBCT) analysis to determine the course of the canal leading to the AIOF., Results: The AIOF incidence was 47.6% (20 crania) and 32.1% of the sides (27 sides). A single AIOF was observed in 24 sides and double AIOF in three sides. The AIOF occurred bilaterally in 7 specimens (16.7%). The majority of AIOF (86.7%) were located superomedial to IOF. A slightly higher frequency of the AIOF was found in left side compared to the right. Using CBCT, a patient sample showed an AIOF incidence in 21 sides of 16 patients (65.6%). A single AIOF was observed in 19 sides. Only 1 double AIOF was found in the scans, whereas 3 were found in the dry skull group. The AIOF occurred bilaterally in 3 scans (10%). The majority of AIOF (90.4%) were located superomedial to the IOF based on the CBCT scans. The AIOF was consistently seen connected to the infraorbital canal and progressed superiorly and medially from the infraorbital canal to the maxillary surface. The size of the ION without an AIOF was not significantly different than the ION in the presence of an AIOF (1.45 × 10/1.32 × 10 μm, P < 0.35) based on fascicular area. However, the number of ION fascicles was greater in specimens without an AIOF compared to those showing this feature (15.15/12.71, P < 0.04) CONCLUSION:: Results indicate that the area of the ION is not affected by an AIOF, suggesting that the field of innervation of this area is not modified by its occurrence. However, the ION appears to divide more proximally into its component branches when the AIOF is present.

Background: Understanding the topography of the blood vessels distributed around the nasolabial fold region is essential for ensuring the safety of dermal filler injections into the nasolabial fold. The purpose of this study was to provide anatomical information on the infraorbital artery distribution and its relationship with the facial artery for use in clinical procedures involving filler injection during nasolabial fold augmentation., Methods: The infraorbital artery was investigated in the nasolabial fold region divided into zones I to XII based on clock-hour meridians centered on the infraorbital foramen. The running layers of the infraorbital artery and infraorbital nerve were also compared in the infraorbital foramen. Changes in the infraorbital artery were observed according to vascular dominance of the facial artery., Results: The infraorbital artery was divided into three main branches, palpebral, nasal, and labial infraorbital artery branches in 34.7, 100, and 100 percent of the specimens, respectively; with these branches of palpebral, nasal, and labial infraorbital artery observed most commonly in zones I, V, and VI, respectively. Analysis of the bilateral facial artery topography revealed that its vascular dominance was observed in 19.4 percent. The infraorbital artery was thicker and had a wider distribution on the nondominant side of the facial artery, whereas the nasal infraorbital nerve anastomosed with the facial artery in the lateral nasal region in 57.1 percent., Conclusion: Investigating and verifying the vascular structure regarding its interactions with the facial artery and infraorbital artery will provide critical information to physicians performing facial surgery and cosmetic procedures.

Background: The course of the nerves along the nasal septum has not been clearly studied, and surgical procedures such as rhinoplasty require a more detailed topography of the nerve supply inside the septum. Therefore, we aimed to investigate the distribution of the internal nasal branch of the infraorbital nerve inside the nasal septum and to define the relationship between it and the nasal cartilages., Methods: Fourteen sides from eight fresh frozen and embalmed Caucasian cadaveric heads were dissected. The specimens were derived from three males and five females. The ages of the cadavers at death ranged from 65 to 84 years. The course of the internal nasal branch and its relationship between the nasal cartilages were observed using a surgical microscope., Results: On all sides, the internal nasal branch approached the medial crus of the major alar cartilage from behind and traveled anteriorly below the medial crus of the major alar cartilage while giving off anterior inferior septal, middle inferior septal, and posterior inferior septal branches., Conclusions: Based on the results of this study, we suggest that procedures of the nasal cavity such as rhinoplasty could be modified to avoid injuring the main trunk of the internal nasal branch of the infraorbital nerve inside the nasal septum., (Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Objectives: The suprazygomatic maxillary nerve block is associated with improved post-operative pain management after select craniofacial surgical procedures. This study's objective is to better define the impact of pediatric facial skeletal growth on techniques for accessing the pterygopalatine fossa (PPF)., Methods: Pediatric patients with prior thin-slice maxillofacial computed tomography imaging were identified in an institutional radiology database. Aquarius image-processing software (Ver. 4.4.11, TeraRecon, Inc., Foster City, CA) was used to measure from the suprazygomatic skin to the greater wing of the sphenoid where the needle is then re-oriented in an anterior and inferior trajectory allowing it to advance into the PPF., Results: A total of 90 patients ranging from 0 to ≤18 years of age were included in the study. The mean distance from the suprazygomatic skin to the foramen rotundum in patients 0 to ≤12 months of age and >13 to ≤18 years of age was 38.6 (SD ± 4.7) and 47.1 (SD ± 3.2) mm, respectively (p < .0001). The statistical analysis demonstrated a positive correlation between age in years and all of the measured distances (p = .0001). With respect to the plane of the needle entry site, the anterior and inferior angles required for passage into the PPF in the 0 to ≤12 months age group were 11 (SD ± 2.1) and 9.0 (SD ± 2.5) degrees, respectively, compared to those in the >13 to ≤18 years of age group at 12.4 (SD ± 1.9) and 12.1 (SD ± 3.2) degrees, respectively. These data reveal that patients in the oldest compared to the youngest pediatric age groups require significantly greater needle insertion, yet the angles of needle re-orientation are clinically similar between these two pediatric age groups varying by up to only 3°., Conclusion: As expected, the distance from the skin to the foramen rotundum increases significantly with age; however, the angles of re-orientation with respect to the original needle entry site demonstrated up to only 3° of variability between the youngest and oldest age groups evaluated in this pediatric cohort., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Patients with facial fracture or head and neck surgery sometimes suffer from infraorbital nerve injury. This injury results in severe hemilateral numbness in the midfacial area. The infraorbital nerve ends with two major branches; the infra nasal branch (INB) and superior labial branch (SLB). In this study, we assessed the feasibility of cross-nerve transfer of the INB and SLB based on a cadaver study., Methods: The INB/SLB from a total 20 sides of 10 cadavers (2 men and 8 women; average age, 79.9 years) were dissected. The distribution patterns of the INB and SLB, the distance between the INB/SLB and the piriform aperture, and the shortest distance between the INB/SLB were estimated., Results: Three distribution patterns of the INB and SLB were observed, that is type A (65%); only the INB is thick enough for a nerve transfer, type B (20%); only the SLB is thick enough for a nerve transfer, and a combination of types A and B (15%). The distance between the INB, SLB and the piriform aperture was on average 8.61 and 10.81 mm in each. The shortest distance between the INB and SLB was on average 11.34 ± 3.7 mm., Conclusions: The INB and SLB existed in all the specimens and could be found approximately 1 cm below the piriform aperture. The average distance between the INB and SLB was approximately 11 mm. These results imply the feasibility of a cross-nerve transfer of the distal part of the infraorbital nerve.

Objectives: To describe the 'blind' and ultrasound-guided approaches to block the maxillary nerve in donkeys. To compare the success and complication rates between the 'blind' and ultrasound-guided techniques based on staining of nerves and other structures in cadavers and assessing level of analgesia in live animals., Study Design: Prospective anatomical and experimental study., Animals: Eighteen cadaver heads and nine adult live donkeys., Methods: Phase 1: the anatomical characteristics of the maxillary nerve and its related structures were investigated within the pterygopalatine fossa in five cadavers. Phase 2: 0.1 mL of methylene blue dye was injected blindly and via ultrasound guidance in 13 cadavers to stain the left and right maxillary nerves, respectively. Nerve staining and dye spreading were evaluated through cadaver dissection. Phase 3: the former procedures were applied in nine live donkeys using lidocaine hydrochloride 2% and the onset of analgesia was verified through needle pricking at the naris., Results: Ultrasound-guided deposition of methylene blue dye in cadavers and lidocaine injection in live animals were successful in all instances (accuracy = 100%) without inadvertent vascular penetration. Using the 'blind' technique, misdirection and intravascular deposition of dye were reported in four cadavers (accuracy = 69.2%) and neurovascular trauma was observed in live donkeys (five cases). Loss of cutaneous sensation in the ipsilateral naris was earlier in the ultrasound-guided approach (10.9 ± 1.8 minutes) than in the 'blind' technique (27.8 ± 3.2 minutes; p < 0.001)., Conclusions and Clinical Relevance: An ultrasound-guided maxillary nerve blockade proved very practical and can be used to block the maxillary nerve with a high degree of accuracy while avoiding vascular penetration. Further studies are mandatory to validate its analgesic effectiveness in clinical situations., (Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Background/aims: This study aimed to examine variations in the location of the infraorbital nerve relative to postoperative maxillary cysts to assess the potential risk of nerve injury during endonasal marsupialization., Methods: Coronal computed tomography images of 130 patients (162 sides) with postoperative maxillary cysts who visited our clinic between 2003 and 2014 were reviewed from the viewpoint of the anatomical relationship between the infraorbital nerves and cysts., Results: The proportions of the six locations were as follows: upside 45.1% (n = 73), separate 13.0% (n = 21), medial 5.6% (n = 9), lateral 14.2% (n = 23), in-between 7.4% (n = 12), and unevaluable 14.8% (n = 24). The proportion of the cases with a potential risk of infraorbital nerve damage during endoscopic marsupialization, including medial, in-between, and unevaluable locations, was 27.8%. Retrospective chart review revealed that 2 patients with a postoperative maxillary cyst that were unevaluable complained of persistent postoperative hypoesthesia of the cheek., Conclusion: The anatomical relationship between the infraorbital nerve and postoperative maxillary cysts varied among patients, with approximately one-fourth of the patients being at risk of infraorbital nerve injury even during endoscopic procedures., (© 2018 S. Karger AG, Basel.)

Purpose: Anatomy of greater palatine foramen is important for maxillary nerve blocks, haemostatic procedures, and the treatment of neuralgia; although metrical data are available about its collocation, still several aspects need to be explored, such as the influence of the cranium size., Methods: The position of greater palatine foramen was assessed on 100 skulls through six measurements (distances from intermaxillary suture, posterior palatal border, posterior nasal spine, and incisive foramen; palatal length; relative position on palatal length) and two angles (angles at incisive foramen and greater palatine foramen). Maximum cranial length, maximum cranial breadth, cranial height and bizygomatic breadth, horizontal cephalic index, and Giardina Y-index were evaluated. Possible differences according to sex and side were assessed through two-way ANOVA (p < 0.05). Measurements showing sexual dimorphism were further assessed through one-way ANCOVA including cranial parameters as covariates (p < 0.05)., Results: Distances of the greater palatine foramen from intermaxillary suture, incisive foramen, posterior palatal border, posterior nasal spine, palatal length, and position of the greater palatine foramen on the palatal length were statistically different according to sex (p < 0.05), independently from general cranial dimensions but for the distance from the posterior palatal border. The angle at the incisive foramen and distances from intermaxillary suture and from posterior nasal spine showed statistically significant differences according to side (p < 0.05)., Conclusions: Results highlight that most of sexually dimorphic measurements useful for pinpointing the greater palatal foramen do not depend upon the cranium size. A more complete metrical assessment of the localization of the greater palatine foramen was provided.

The internal nasal branch of the infraorbital nerve (ION) runs down the nose and around the ala to be distributed to the nasal septum and vestibule. The aim of this study was to measure the internal nasal branch around the ala of the nose and discuss its possible relevance in clinical/surgical practice. Twelve sides from seven specimens derived from fresh frozen and embalmed Caucasian cadaveric heads were dissected. The specimens included three males and four females. The ages of the cadavers at death ranged from 65 to 84 years. The diameter of the internal nasal branch, horizontal distance from the lateral contour of the ala (Point A) to the branch (distance H) and vertical distance from the bottom part of the ala (Point B) to the branch (distance V) were recorded. Distance H ranged from -1.6 to 1.5 mm on right sides and -1.0 to 1.5 mm on left sides. The diameter of the nerves at Point A ranged from 1.3 to 1.8 mm on right sides and 1.3 to 1.6 mm on left sides. Distance V ranged from -1.5 to 1.0 mm on right sides and -2.3 to 1.1 mm on left sides. The diameter of the nerves at Point B ranged from 0.7 to 1.3 mm on right sides and 0.8 to 1.2 mm on left sides. The results of this study are the first to detail the topography of the internal nasal branch of the ION. Clin. Anat. 30:817-820, 2017. © 2017Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

The sensory innervation of the inferior eyelid is mainly derived from the inferior palpebral branch (IPb) of the infraorbital nerve (ION). This study aimed to investigate another, to our knowledge, previously unknown branch, and elucidate its location and distribution. Twelve sides from seven fresh frozen cadaveric Caucasian heads were used in this study. The specimens were derived from two male and four female adult cadavers age. The diameter of the IPb of the ION (D1) and branch arising from the upper wall of the infraorbital canal (D2), and distance between the branching points of this branch and the anterior border of the orbit floor (L1) was measured. A branch to the lower eyelid was found arising from the infraorbital canal on the majority of sides. D1 ranged from 0.4 to 1.1 mm. The branch arising from the upper wall of the infraorbital canal was found 10 sides (83%). D2 ranged 0.6 to 1.0 mm. L1 ranged from 10.2 to 19.8 mm. All of the branches arising from the upper wall of the infraorbital canal (10 sides) primarily innervated to the inferior eyelid. We suggest this branch should be named the "posterior IPb" of the ION. Knowledge of this branch might decrease sensory loss following invasive procedures of the lower orbit. Clin. Anat. 30:835-838, 2017. © 2017Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

Background: The maxillary nerve (V2) can be approached via the open middle fossa approach., Objective: To delineate the anatomy of V2 and its specific segments with respect to the endonasal landmarks. We present the endoscopic endonasal interdural middle fossa approach to V2 and its potential application for the treatment of perineural spread in sinonasal/skull base tumors., Methods: Five human head silicon-injected specimens underwent bilateral endoscopic endonasal transpterygoid approaches. V2 prominence and the maxillary strut were identified in the lateral recess along with paraclival carotid protruberance. The regions superior and inferior to V2 corresponding to the anteromedial and anterolateral triangles of the middle fossa were exposed., Results: V2 can be classified into 3 segments: interdural (from the Gasserian ganglion to the proximal part of the maxillary strut), intracanalicular (corresponding to the anteroposterior length of the maxillary strut), and pterygopalatine (distal to the maxillary strut and the site of its divisions). Endonasally, the average length of the interdural and the intracanalicular segments were approximately 9 and 4.4 mm, respectively. V2, following its division distal to the maxillary strut, was successfully dissected off the middle fossa dura and transected just distal to the Gasserian ganglion., Conclusion: Endonasally, the interdural segment can be safely mobilized between the periosteal and meningeal dural layers while ensuring the integrity of the middle fossa dura. This allows transection of infiltrated V2 to facilitate tumor resection without entering the intradural/arachnoidal space. Posteriorly, this is limited by the Gasserian ganglion and superomedially by the dural envelope surrounding the cavernous sinus and the paraclival carotid artery., (Copyright © 2017 by the Congress of Neurological Surgeons)

Objective: The aim of this preliminary proof-of-concept study was to evaluate and compare the success and complication rate of infiltration of the maxillary nerve of cadaver heads using previously described surface landmarks, standard ultrasound and a novel needle guidance positioning ultrasound system (SonixGPS)., Study Design: Prospective, anatomical, method-comparison study., Animals: Thirty-eight equine cadaver heads., Methods: Twenty-six veterinary students performed the three methods consecutively on cadaver heads using an 18 gauge, 8.9 cm spinal needle and 0.5 mL iodinated contrast medium. Computed tomography was used to quantify success (deposition of contrast in contact with the maxillary nerve) and complication rate (contrast identified within surrounding vasculature or periorbital structures) associated with each method., Results: Perineural injection of the maxillary nerve was attempted 76 times, with an overall success rate of 65.8% (50/76) and complication rate of 53.9% (41/76). Success rates were 50% (13/26) with surface landmark, 65.4% (17/26) with standard ultrasound guidance and 83.3% (20/24) with SonixGPS guidance approaches (Fisher's exact test, p=0.046). No significant difference in complication rate was found between the three methods., Conclusions: Ultrasound-guided maxillary nerve blocks were significantly more successful than surface landmark approaches when performed by inexperienced operators, and the highest success rate was achieved with guidance positioning system (GPS) needle guidance., Clinical Relevance: Local anaesthesia of the equine maxillary nerve in the fossa pterygopalatina is frequently used for diagnostic and surgical procedures in the standing sedated horse. Due to vague superficial landmarks with various approaches and the need for experience via ultrasound guidance, this block remains challenging. GPS guidance may improve reliability of maxillary and other nerve blocks, and allow a smaller volume of local anaesthetic solution to be used, thereby improving specificity and reducing the potential for side effects., (Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

The infraorbital nerve (ION) can easily be damaged by orbital trauma and periorbital surgical manipulations, due to its abutment to the orbital floor. Anatomic variability of the ION and surrounding structures has infrequently been documented. The aim of this study is to give precise anatomical knowledge about the ION with surrounding structures, to avoid iatrogenic injury of the ION during periorbital procedures.Forty orbits of 40 skull subjects (20 males and 20 females) were studied to analyze structures around the ION. The authors located the ION, infraorbital canal/groove (IOC/G), and infraorbital foramen (IOF), using several reference points. The various distances were also measured between those structures, and statistically analyzed. The authors compared the left and right sides, and analyzed the differences between both sexes. The IOF was also investigated regarding the shape and presence of the accessory IOF.Three different types of orbital floor osseous anatomy were made based on macroscopic analysis. Type 1 shows no groove, and the ION enters the canal covered by the roof (5 patients, 12.5%). Type 2 revealed a pseudocanal, which has a very thin, almost transparent roof (26 patients, 65.0%). Type 3 consists of the ION traveling in a true groove, before entering an IOC (9 patients, 22.5%). IOG/C complexes took the upward lateral course, until exiting via the IOF. The mean ± SD length of the IOC was 12.86 ± 3.79 mm, and of the IOG was 16.15 ± 2.88 mm. The calculated combined mean length of the IOC/G complex was found to be 29.01 ± 3.17 mm. An accessory IOF was found in 35% of the skulls (50% in male and 20% in female skulls), with a higher frequency on the left side in both male and female skulls.These results can increase the authors' knowledge of the anatomic variability of the infraorbital region, and help facial plastic surgeons during their surgical manipulations prevent any possible iatrogenic injury of the ION.

Competing Interests: Disclosure: Dr Hersh, representing the Trustees of the University of Pennsylvania, has received grant monies from St. Renatus, LLC, for being a principal investigator on clinical trials that led to FDA approval of Kovanaze.

Myelination, the ensheathing of neuronal axons by myelin, is important for the proper function of both central and peripheral nervous systems. Various studies have investigated the quantitative parameters of myelination in certain species. Pigs are among the species of which their use as laboratory animals in neuroscience research increased the past few decades. However, there is limited data regarding the myelination process in the pig. Moreover, the maxillary nerve is crucial for Pseudorabies Virus (PrV) neuropathogenesis. In this context, a quantitative analysis of various myelination parameters of the maxillary nerve was performed, during the first 5 weeks of porcine post-natal development, the time period, which exhibits the highest interest for PrV neuropathogenesis. The evaluation was conducted in four groups of uninfected pigs, at the time of birth (group 0w), at the age of 1 week (group 1w), 3 weeks (group 3w) and 5 weeks (group 5w), using toluidine blue staining, immunofluorescence and electron microscopy. Axon and fibre diameter, perimeter and surface, myelin sheath thickness and g-ratio were measured on histological sections transverse to the longitudinal axis of the maxillary nerve. The thickness of myelin sheath was 0.76 μm for group 0w, 0.94 μm for group 1w, 0.98 μm for group 3w and 1.03 μm for group 5w. The g-ratio was 0.529, 0.540, 0.542 and 0.531 for the respective animal groups. The results of this study contribute to the understanding of the myelination process in the pig will be used for the study of PrV effects on the myelination development of newborn piglets' maxillary nerve and may shed new light to their vulnerability to the virus., (© 2016 Blackwell Verlag GmbH.)

Objective: Investigation of the computerized dimensional anatomic location of the greater palatine foramen (GPF) and lesser palatine foramens (LPF) is important indicating site to collect palatal donor tissue, reconstructioning the orofacial area of the oncology patient and applying the greater palatine nerve block anesthesia. The aim of this study is to determine a patient-friendly landmark and to specify the precise location of the GPF in order to standardise certain anatomical marks of safe neurovascular bundle., Materials and Methods: 120 bony palates were examined to detect the position of the GPF and the LPF related to adjacent anatomical landmarks using a computer software program. The GPF was assessed regarding the position, the diameter and the distances between each foramen and the midline maxillary suture (MMS), the inner border of alveolar ridge (AR), posterior palatal border (PBB), and incisive foramen (IF)., Results: The GPF was identified as single in 81 %, double in 16 %, triple in 2 % and absent in 2 % of the specimens. The mean distances between the GPF and the MSS, the GPF and the AR, the GPF and the PPB, the GPF and the IF were 16, 4, 4, and 40 mm, respectively. In majority of the cases, the GPF was seen between the distal surfaces of the third maxillary molar (78 %). Single LPF was observed in 53.45 % of the skulls, two LPF were observed in 31 % of the skulls bilaterally and five LPF were rare in 2.1 % of the specimens. The LPF was most commonly at the junction of the palatine bone and the inner lamella of the pterygoid plate (71.9 %)., Conclusions: This study made possible to investigate the variability of the GPF and the feasibility of the greater palatine neurovascular bundle, and to calculate the lengths of some parameters with the help of certain software. To collect the donor tissue of the neurovascular greater palatine network, each distance among the AR-GPF-PPB were equal to 4 mm. To estimate the possible length of the graft, the incision was made along the third and the second molar to the IF as 4 cm. The data we obtained within this study have been presented to help the surgeons avoid unexpected hemorrhage during the palatinal procedures such as posttraumatic dental reconstruction, maxillofacial tumor resections, palatal micro-implants, and dentofacial orthopedic surgery.

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.

OBJECTIVE Endoscopic transmaxillary approaches (ETMAs) address pathology of the anterolateral skull base, including the cavernous sinus, pterygopalatine fossa, and infratemporal fossa. This anatomically complex region contains branches of the trigeminal nerve and external carotid artery and is in proximity to the internal carotid artery. The authors postulated, on the basis of intraoperative observations, that the infraorbital nerve (ION) is a useful surgical landmark for navigating this region; therefore, they studied the anatomy of the ION and its relationships to critical neurovascular structures and the maxillary nerve (V2) encountered in ETMAs. METHODS Endoscopic anatomical dissections were performed bilaterally in 5 silicone-injected, formalin-fixed cadaveric heads (10 sides). Endonasal transmaxillary and direct transmaxillary (Caldwell-Luc) approaches were performed, and anatomical correlations were analyzed and documented. Stereotactic imaging of each specimen was performed to correlate landmarks and enable precise measurement of each segment. RESULTS The ION was readily identified in the roof of the maxillary sinus at the beginning of the surgical procedure in all specimens. Anatomical dissections of the ION and the maxillary branch of the trigeminal nerve (V2) to the cavernous sinus suggested that the ION/V2 complex has 4 distinct segments that may have implications in endoscopic approaches: 1) Segment I, the cutaneous segment of the ION and its terminal branches (5-11 branches) to the face, distal to the infraorbital foramen; 2) Segment II, the orbitomaxillary segment of the ION within the infraorbital canal from the infraorbital foramen along the infraorbital groove (length 12 ± 3.2 mm); 3) Segment III, the pterygopalatine segment within the pterygopalatine fossa, which starts at the infraorbital groove to the foramen rotundum (13 ± 2.5 mm); and 4) Segment IV, the cavernous segment from the foramen rotundum to the trigeminal ganglion (15 ± 4.1 mm), which passes in the lateral wall of the cavernous sinus. The relationship of the ION/V2 complex to the contents of the cavernous sinus, carotid artery, and pterygopalatine fossa is described in the text. CONCLUSIONS The ION/V2 complex is an easily identifiable and potentially useful surgical landmark to the foramen rotundum, cavernous sinus, carotid artery, pterygopalatine fossa, and anterolateral skull base during ETMAs.

The aim of this study was to investigate a new approach for equine maxillary nerve blocks, which can facilitate several orofacial surgeries. Current techniques aim at the maxillary foramen and approach via the zygomatic arch, conferring the risk of injury to several delicate structures in the target area. To investigate the feasibility of a retrograde approach from the infraorbital foramen, an anatomic study of the infraorbital canal and its surrounding structures was performed on 13 cadaveric skulls using computed tomography and anatomical dissection. Measurements included canal length and volume, its conformation and relationship with the enclosed structures, and infraorbital foramen diameters. The technical approach to simulate the distribution of local anaesthetic within the infraorbital canal was further defined, including needle selection among seven different needles, evaluating ease of insertion, trauma to surrounding tissues and spread of contrast medium toward the target area. To validate the technique, two Tuohy needles were randomly inserted at 12 infraorbital foramina and 10 mL of contrast medium was injected. CT verified the spread of the solution and possible complications. Each canal had a serpentine-curved pathway. Anatomical dissections evidenced gaps between the infraorbital nerve, vessels and the infraorbital canal. The integrity of these structures had been preserved from the passage of the selected Tuohy needles. This study suggests a feasible approach to the maxillary nerve block within the infraorbital canal providing an appropriate needle selection and technique to limit complications., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: The infraorbital nerve (ION) is at risk for iatrogenic injury during orbital floor repair. The authors aim to anatomically characterize the intraosseous course of the ION between the inferior orbital fissure and infraorbital foramen., Methods: Ten cadaver heads (20 orbits) were dissected, with exposure of the orbital floor. The ION was identified from the infraorbital fissure to inferior orbital foramen. The presence and caliber of an osseous roof was noted. Distances measured were infraorbital foramen to infraorbital margin; length of the inferior orbital groove; length of the inferior orbital canal; length from the inferior orbital fissure to the infraorbital margin., Results: Three variations of the osseous anatomy around the ION were identified. Four cadavers had no identifiable groove (Type 1, 40%) and the ION was completely roofed throughout its course. Five specimens exhibited a thin, transparent osseous roof over the nerve before forming the true canal, which we describe as a "pseudocanal" (Type 2, 50%). A true groove was seen in both orbits from a single cadaver (Type 3, 10%). Each cadaver had an ION course of the same type on both sides. Mean ± SD intraorbital foramen to infraorbital margin distance was 7.1 ± 1.4 mm. Distance from the infraorbital fissure to the infraorbital margin was 28.5 ± 2.3 mm., Conclusions: The course of the infraorbital nerve can be described as Type 1 (true canal), Type 2 (pseudocanal), and Type 3 (groove and canal). The authors propose that this novel classification system will raise awareness of variations in orbital floor anatomy.

The aim of this study was to assess the presence, location and, multiplanar distance of the canalis sinuosus (CS) between the incisive foramen and the anterior maxillary alveolar ridge using cone beam computed tomography (CBCT). Therefore, 500 CBCT maxillary images obtained from male and female patients aged 20 to 80 years were selected to assist in the dental treatment. Low-quality tomographic images were discarded. All images were captured with the i-CATTM Classic tomograph and assessed using the XoranCatTM software. The axial sections were analyzed at the incisive foramen in order to verify the CS presence in laterality and location. Furthermore, linear measurements of the nasal cavity floor, buccal cortical bone, and alveolar ridge crest were made. All the collected data were statistically analyzed. Results show a variation of the CS in relation to the classification and distance of anatomical structures, but no significant difference between the right and left sides. It should be highlighted that CBCT is necessary before invasive procedures in order to preserve important anatomical structures. In conclusion, the location of the CS varies in relation to the alveolar ridge crest and buccal cortical bone, assuming that it is going to be located by the upper lateral incisor palatine.

Background: Posttraumatic midface pain secondary to injury of the anterior superior alveolar nerve (ASAN) is characterized as pain localized to the central and lateral incisors, canines, and maxilla. This nerve is susceptible to injury and subsequent formation of neuromas after midface trauma. Surgical intervention requires an accurate and precise understanding of the course of the ASAN., Methods: Dissections of 12 human cadaver heads were conducted to identify the course of the ASAN through the canalis sinuosus (CS). Fifty 1-mm slice face computed tomographic scans were evaluated to document the dimensions and course of the CS., Results: The ASAN branched laterally from the infraorbital nerve before reaching the infraorbital rim in all cadavers. The bifurcation occurred 18 mm posterior to the infraorbital rim (range, 10-30 mm). At a point 25 mm inferior to the infraorbital rim, the ASAN is found 3.4 mm lateral to the piriform aperture (range, 3-4 mm). Radiographic analysis demonstrated a 12.9-mm horizontal length of the CS across the anterior maxilla (SD, 2.2 mm), a distance of 4.8 mm between the piriform aperture and the CS (SD, 1.2 mm), and 11.7 mm vertical length of the CS along the piriform aperture (SD, 3.0 mm)., Conclusions: The ASAN maintains consistent coordinates at specific points along its course through the midface. An improved understanding of the course of the ASAN will guide future diagnosis of injury to this nerve and surgical intervention for patients with posttraumatic midface pain secondary to ASAN injury.

The canalis sinuosus (CS) is a neurovascular canal, a branch of the infraorbital canal through which the anterior superior alveolar nerve passes. There are no studies or case reports of anatomical variations related to this canal. A rare case of anatomical variation in the CS is reported that was detected by cone beam computed tomography done in a 47-year-old female as a pre-operative workup before dental implants. In this case, in the region slightly medial to tooth 23, a wide accessory branch from the CS was observed, running an intraosseous course in the inferior and posterior direction up to a foramen located in the hard palate, slightly medial in relation to tooth 23. The location of this branching, as well as its neurovascular component, is important for dental implant planning because of its proximity to the upper teeth. Identification of neurovascular bundles is fundamental to avoid complications for the patient.

The aim of the article is to elucidate the communications between the trigeminal nerve and facial nerve in the face. In a PubMed search, 328 studies were found using the terms 'trigeminal nerve, facial nerve, and communication.' The abstracts were read and 39 full-text articles were reviewed. Among them, 11 articles were analyzed. In the studies using dissection, the maxillary branch (V2) had the highest frequency (95.0% ± 8.0%) of communication with the facial nerve, followed by the mandibular branch (V3) (76.7% ± 38.5%). The ophthalmic branch (V1) had the lowest frequency of communication (33.8% ± 19.5%). In a Sihler stain, all of the maxillary branches and mandibular branches had communications with the facial nerve and 85.7% (12/14 hemifaces) of the ophthalmic branches had communications. The frequency of communications between the trigeminal nerve and facial nerve were significantly higher (P = 0.00, t-test) in the studies using a Sihler stain (94.7% ± 1.1%) than the studies using dissection (76.9 ± 35.8). The reason for the significantly higher frequency of trigeminal-facial communication in the studies using a Sihler stain is because of the limitation of the Sihler stain itself. This technique cannot differentiate the motor nerves from sensory nerves at the periphery, and a crossover can be misinterpreted as communication near to nerve terminal.

Objectives/hypothesis: To assess relevant variations in the anatomical course of the infraorbital nerve (ION). This understanding may reduce the risk of surgical injury., Methods: A total of 100 consecutive computed-tomography sinus studies obtained in a tertiary referral center were reviewed, and measurements were made of the 200 IONs. Anatomic variants were classified into three types based on the degree to which (if any) the nerve's course descended from the maxillary roof into the sinus lumen., Results: A total of 60.5% of IONs were entirely contained within the sinus roof. In 27.0%, the nerve canal descended below the roof but remained juxtaposed to it. In 12.5%, the ION descended into the sinus lumen. The proportion of IONs descending into the sinus significantly increased to 27.7% when an infraorbital ethmoid cell was present (chi-square P < 0.001) and to 50% when the nerve was contained within a lamella of such a cell (chi-square P < 0.001). Descended nerves terminated in a foramen located an average of 11.9 ± 2.5 mm below the infraorbital rim, significantly further below the orbit than nondescended nerves (t test P < 0.001). Descended nerves were located a mean distance of 8.6 ± 2.9 mm below the sinus roof and traversed the sinus lumen diagonally for a mean length of 15.4 ± 3.1 mm., Conclusions: Descent of the ION into the maxillary sinus is a common anatomic variant that is more prevalent in the setting of an ipsilateral infraorbital ethmoid cell. Descended nerves are associated with the foramen significantly further below the inferior orbital rim than those of nondescended nerves. These observations may help surgeons avoid iatrogenic ION injury., Level of Evidence: N/A., (© 2015 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The surgical anatomy of the midface relevant to its subperiosteal elevation and repositioning is assessed., Objectives: The aim of this study is to give more details on the anatomy relevant to the midface lift., Methods: Twenty hemifacial dissections were performed. The location of the zygomatic branches of the facial nerve (ZBFN) and the terminal branches of the infraorbital nerve (ION) were dissected. The location of the masseteric and zygomatic ligaments and the elevation of midface following their release were documented., Results: On average, there were 3 branches of the facial nerve innervating the zygomatic major muscle and 1.8 branches entering the muscle superior to the caudal origin of the zygomaticomaxillary (ZM) suture. The most superior ZBFN was found to lie at an average of 6.2 ± 1.6 mm cranial to ZM suture and 1.4 ± 0.4 mm superficial to the bone. The most inferior branch was at a mean of 4.8 ± 3.3 mm inferior to ZM suture. On average the ION had 5.2 branches that traveled for 10.2 mm above the periosteum before they passed into a superficial plane. Division of the zygomatico-masseteric retaining ligaments allowed for elevation of the midface by 4.8 ± 1.0 mm medially and 5.5 ± .9 mm laterally., Conclusions: Branches of the ZBFN and ION lie in close proximity to the subperiosteal plane in the midface. These branches are at risk for damage during release of the upper zygomatic ligaments and placement of the periosteal suspension sutures during midface elevation procedures., (© 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.)

In order to understand the underlying principles of orofacial pain it is important to understand the corresponding anatomy and mechanisms. Paper 1 of this series explains the central nervous and peripheral nervous systems relating to pain. The trigeminal nerve is the 'great protector' of the most important region of our body. It is the largest sensory nerve of the body and over half of the sensory cortex is responsive to any stimulation within this system. This nerve is the main sensory system of the branchial arches and underpins the protection of the brain, sight, smell, airway, hearing and taste, underpinning our very existence. The brain reaction to pain within the trigeminal system has a significant and larger reaction to the threat of, and actual, pain compared with other sensory nerves. We are physiologically wired to run when threatened with pain in the trigeminal region and it is a 'miracle' that patients volunteer to sit in a dental chair and undergo dental treatment. Clinical Relevance: This paper aims to provide the dental and medical teams with a review of the trigeminal anatomy of pain and the principles of pain assessment.

The aim of this study was to identify the shape and route of the bony canal of the posterior superior alveolar artery (PSAA) and posterior superior alveolar nerve (PSAN) using different identification methods, including computed tomography (CT), panoramic radiograph, and macroscopic evaluation (corpse and dry skull). Twenty-four patients were analyzed by CT and panoramic and posterior anterior (PA) radiographs; additionally, 90 dry skulls and 21 dissected anatomical specimens were examined. Three-dimensional-CT revealed that the lateral wall of the maxillary sinus resembled a tunnel format in 60% of the treated patients. Out of all 24 patients, the panoramic radiograph identified the bony canal in only one patient; whereas the PA radiograph identified it in 80% of the patients. The dry skulls showed tunnellike routes of the PSAA and PSAN in 65% of the cases. Moreover, the pathway was also visibly observed in the dissected anatomical specimens as a straight shape in 85% of the cases. Thus, our results demonstrated that the most common shape of the bony canal of the PSAA and PSAN is the tunnel format with a straight route by 3D-CT, posterior anterior radiography, and macroscopic evaluation. However, in the panoramic radiographs, it was difficult to identify this canal.

The greater palatine nerve and the greater palatine canal are common sites for maxillary anesthesia during dental and maxillo-facial procedures. The greater palatine nerve is thought to course as a single trunk through the greater palatine canal, branching after its exit from the greater palatine foramen. We describe intra-canalicular branching variations of the greater palatine nerve found in 8 of 20 embalmed dissection specimens. Such variation is previously unreported in the literature. We characterize the variations in branching pattern and discuss the possible implications for clinical practice.

Object: The objective of this study was to develop an electrophysiological method for intraoperative localization of the trigeminal nerve branches during radiofrequency thermocoagulation (RFTC)., Methods: Twenty-three patients who were scheduled to undergo RFTC were included. The trigeminal nerve root was stimulated through the foramen ovale using the radiofrequency cannula. Antidromic responses were recorded from the target division through supraorbital, infraorbital, and mental foramina electrodes, and an additional electrode at the masseter muscle. Sensory and motor action responses, as well as verbal and masseter contraction responses, were recorded and correlated., Results: The antidromic responses were easily recorded in the target division in all 23 patients, and they were invariably correlated with the patient's verbal responses. The potentials were recorded successively from V1 to V3. The amplitude in each division before and after RFTC showed little difference in response to electrical stimulation with the same current. The motor trigeminal nerve action potentials were recorded in 10 patients; 7 of these patients had postoperative masseter muscle weakness, while the remaining 3 had normal masseter muscle function. Potentials with low amplitudes were usually obtained from neighboring divisions, but no unexpected denervation of any branches was observed. All the patients experienced immediate pain relief after the procedure., Conclusions: This technique is sensitive and easy to apply. The sensory and motor potentials matched the verbal responses and the complications. Although it cannot completely substitute for the patient's verbal response, this approach is helpful in uncooperative patients, and it predicts and reduces the incidence of masseter muscle weakness. The use of these complementary techniques could increase the chances of treatment success.

Purpose: Various studies have been conducted on morphometric variations of infraorbital foramen to provide data to surgeons for nerve block in infraorbital region. This study aims to analyse the anatomical variations by comparing various morphometric measurements of infraorbital foramen in dry skulls of adult North Indian population. This study becomes relevant in the present study group as very scant data is available about the variations and morphometric measurements in Indian population. The data thus collected can be standardized and become useful for the surgeons working in this area of face., Materials and Methods: The study was conducted on 75 dry adult human skulls, which were a part of Department of Anatomy, used for teaching purposes in medical colleges. Straight distance of the Infraorbital foramen from the infraorbital rim, supraorbital foramen and sagittal plane was measured. The position of the infraorbital foramen was determined in relation to maxillary teeth and supraorbital foramen. The data thus obtained was analysed., Results: The distance of infraorbital foramen from infraorbital rim, supraorbital foramen, sagittal plane in the present study was found to be 6.71 ± 1.11 mm, 42.02 ± 4.31 mm and 31.94 ± 4.88 mm respectively. The position of infraorbital foramen was lateral in relation to supraorbital foramen (in 88% of cases). Infraorbital foramen was above the 1st premolar tooth in most of the cases. Accessory infraorbital foramen was found in 11.2% cases (double foramen)., Conclusion: The data thus obtained will perhaps be helpful to the surgeons in identifying the extent of the operative field thereby reducing procedural risks., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background: Anatomical landmarks in children are mostly extrapolated from studies in adults. Despite this, complex regional anesthetic procedures are frequently performed on pediatric patients. Sophisticated imaging techniques are available but the exact position, course and/or relationships of the structures are best understood with appropriate anatomical dissections. Maxillary nerve blocks are being used for peri-operative analgesia after cleft palate repair in infants. However, the best approach for blocking the maxillary nerve in pediatric patients has yet to be established., Objective: To determine the best approach for blocking the maxillary nerve within the pterygopalatine fossa., Methods: In an attempt to define an optimal approach for maxillary nerve block in this age group three approaches were simulated and compared on 10 dried pediatric skulls as well as 30 dissected pediatric cadavers. The needle course, including depth and angles, to block the maxillary nerve, as it exits the skull at the foramen rotundum within the pterygopalatine fossa, was measured and compared. Two groups were studied: Group 1 consisted of skulls and cadavers of neonates (0-28 days after birth) and Group 2 consisted of skulls and cadavers from 28 days to 1 year after birth., Results: No statistically significant difference (P > 0.05) was found between the left and right side of each skull or cadaver. Only technique B, the suprazygomatic approach from the frontozygomatic angle towards the pterygopalatine fossa, exhibited no statistical significance (P > 0.05) when other measurements made on the skulls and cadavers were compared. Technique A, a suprazygomatic approach from the midpoint on the lateral border of the orbit, as well as technique C, an infrazygomatic approach with an entry at a point on a vertical line extending along the lateral orbit wall, showed statistical significant differences when measurements of the skulls and cadavers were compared., Conclusions: On the basis of these findings technique B produces the most consistent data for age groups 1 and 2 and supports the clinical findings recently reported., (© 2014 John Wiley & Sons Ltd.)

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement.

Object: The aim in this paper was to localize and detect incipient damage to the ophthalmic and maxillary branches of the trigeminal nerve during tumor surgery., Methods: This was an observational study of patients with skull base, retroorbital, or cavernous sinus tumors warranting dissection toward the cavernous sinus at a university hospital. Stimuli were applied as normal during approach to the cavernous sinus to localize cranial nerves (CNs) III, IV, and VI. Recordings were also obtained from the facial muscles to localize CN VII. The trigeminofacial reflex was sought simply by observing a longer time base routinely., Results: Clear facial electromyography responses were reproduced when stimuli were applied to the region of V1, V2, and V3. Response latency was increased compared with direct CN VII stimuli seen in some cases. Responses gave early warning of approach to these sensory trigeminal branches., Conclusions: The authors submit this as a new technique, which may improve the chances of preserving trigeminal sensory branches during surgery in this region.