Localization of important facial foramina encountered in maxillo-facial surgery

Knowledge of the location of foramina in the maxillo-facial region is necessary in clinical situations requiring regional nerve blocks and in open as well as endoscopic surgical procedures to avoid injury to corresponding nerves. In this study, measurements were taken on 79 adult dried human skulls to determine the position of the supraorbital, infraorbital, and mental foramina. Supraorbital foramina were found to be approximately 25 mm lateral to the midline, 30 mm medial to the temporal crest of the frontal bone, and 2-3 mm superior to the supraorbital rim. Additional exits for branches of the supraorbital nerve were present in 14% of skulls. The intersection of the zygomatico-maxillary suture with the inferior orbital rim was a readily palpable landmark for locating the infraorbital foramen. This foramen was approximately 7 mm inferior to the inferior orbital rim and 28.5-mm lateral to the midline. Mental foramina were on average, 25.8-mm lateral to the midline and about 13-mm superior to the inferior mandibular margin. Both the infraorbital and mental foramina were most often on a vertical line with the second premolar (Position 3). The distances of the foramina from the midline were similar on both sides demonstrating facial symmetry. In about 80% of skulls, the supraorbital, infraorbital, and mental foramina/notches were along the same vertical line. These measurements may be of value to clinicians in localizing and safeguarding these nerves and providing effective nerve blocks.     

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

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

Morphometric measurements from various reference points in the orbit of male Caucasians

The aim of this study was to determine the morphometric variations from various reference points to decrease risks in orbital surgery. Sixty-two orbits obtained from 31 skulls of male adult Caucasians were measured with a millimetric compass. On the medial orbital wall, the midpoint of the anterior lacrimal crest was the reference point; from this point we measured distances of 23.9+/-3.3 mm, 35.6+/-2.3 mm, 41.7+/-3.1 mm and 6.9+/-1.5 mm respectively to the anterior ethmoidal foramen, posterior ethmoidal foramen, midpoint of the medial aspect of the optic canal and posterior lacrimal crest. On the same wall, distances from the plane of the anterior and posterior ethmoidal foramina to the ethmoido-maxillary suture and distance from the posterior ethmoidal foramen to the anterior ethmoidal foramen and midpoint of the medial margin of the optic canal were 14.9+/-2.3 mm, 9.8+/-2.9 mm and 6.8+/-2.2 mm respectively. On the inferior orbital wall, the main reference point was the infraorbital foramen, and from this point to the midpoints of the lateral margin of the fossa for the lacrimal gland, inferior orbital fissure, inferior orbital rim and inferior aspect of the optic canal was 23.8+/-7.2 mm, 31.9+/-3.9 mm, 6.7+/-1.9 mm and 50.3+/-3.2 mm respectively. On the superior orbital wall, the distances from the supraorbital foramen to the midpoints of the superior orbital fissure, fossa for the lacrimal gland and superior aspect of the optic canal were 45.7+/-3.6 mm, 26.0+/-2.5 mm and 45.3+/-3.2 mm respectively. Furthermore, on the same wall, the distance from the posterior ethmoidal foramen to the midpoint of the superior orbital fissure was 14.6+/-2.8 mm. Finally, on the lateral orbital wall the frontozygomatic suture was the reference point. From this point distances to the midpoints of the fossa for the lacrimal gland, superior orbital fissure, lateral aspect of the optic canal and inferior orbital fissure were 17.5+/-2.1 mm, 37.7+/-3.6 mm, 44.9+/-2.5 mm and 33.4+/-3.1 mm respectively.     

应用鼻翼和口角定位眶下孔和颏孔的应用解剖学研究

目的：应用鼻翼和口角标记定位眶下孔和颏孔,为颌面外科手术避免损伤出入两孔的血管神经提供应用解剖学资料。方法：取30例10％甲醛溶液固定尸体头部标本,解剖暴露眶下孔和颏孔。眶下孔和颏孔测量点为各自中心点,鼻翼测量点为鼻翼外侧下脚。测量两侧眶下孔、颏孔、鼻翼及口角之间的距离,眶下孔和颏孔最大径,鼻翼至经眶下孔垂直线的垂直距离、眶下孔至经鼻翼水平线的垂直距离、眶下孔至鼻翼直线距离,口角至经颏孔水平线的垂直距离、颏孔至经口角垂直线的垂直距离、颏孔至口角直线距离。结果：眶下孔定位在鼻翼上方（13．9±3．6）mm,向外（6．7±2．8）mm处;眶下孔与鼻翼间直线距离为（16．4±3．2）mm。颏孔定位在口角下方（20．6±2．9）mm,向内（3．4±3．1）mm处;颏孔与口角间直线距离为（21．7±3．3）mm。结论：以鼻翼和口角为标记定位眶下孔及颏孔位置,有助于临床避免损伤出入两孔的血管神经。     

Location and incidence of the zygomaticofacial foramen: An anatomic study

The location and incidence of the zygomaticofacial foramen (ZFF) was studied in 80 dry skulls (160 sides) of unsexed adult skulls of West Anatolian people. The average distances from the ZFF to the frontozygomatic suture, to the zygomaticomaxillary suture, and to the inferior orbital rim were found to be 26.2 ± 3.2 mm, 18.6 ± 3.14 mm, and 5.94 ± 1.43 mm, respectively. The zygomas were evaluated for the number of foramina on their facial aspects. There was none in 25 (15.6%), one in 71 (44.4%), two in 45 (28.1%), three in 10 (6.3%), four in seven (4.4%), and five in two (1.3%) sides. The ZFF was also studied for its distribution around the zygoma by dividing the surface into four anatomical areas. There was no statistical difference between the morphometrical results on both sides. Data regarding the location and variation in the number of the ZFF is important in avoiding zygomatic nerve and vessel injury during surgery, but by virtue of the great variability found, ZFF is an unreliable landmark for maxillofacial surgery. Clin. Anat. 22:559–562, 2009. © 2009 Wiley‐Liss, Inc.     

国人眼眶容积及骨性径线测量

目的　为眼眶手术安全和眼眶重建术提供形态学资料。方法　应用摩立逊定位仪、游标卡尺等工具对 30例骨性眼眶进行解剖测量。结果　眶外侧缘点至眶上裂距离为 35 2 5mm ;眶外侧缘点至视神经孔外侧缘距离为 4 8 4 0mm ;眶下点至眶上裂距离为 4 5 6 2mm ;眶下点至眶下裂距离为 19 5 8mm ;眶下点至视神经孔外侧缘距离为 5 2 0 8mm ;眶内侧缘点至筛前孔距离为 18 5 9mm ;眶内侧缘点至筛后孔距离为 32 4 9mm ;眶内侧缘点至视神经孔内侧缘距离为 4 1 15mm ;眶上切迹至眶上裂距离为 39 0 4mm ;眶上切迹至视神经孔上缘距离为 4 5 93mm ;眶上缘中点至视神经孔上缘距离为 4 7 13mm ;眶下点至眶上裂距离为 4 5 35mm ;眶下缘中点至视神经孔外缘距离为 4 9 6 4mm ;眶深为 4 9 6 4mm ;颅最大长度为 175 34mm ;眶容积为 2 7 0 0ml。结论　同一个体双侧眼眶除了眶下点至视神经孔外侧缘距离右眼大于左眼 (P =0 0 16 )外 ,其他无显著差异 ;眶深与颅最大长度无直线相关关系。     

Ultrasound imaging of the infraorbital foramen and simulation of the ultrasound-guided infraorbital nerve block using a skull model

Purpose

Infraorbital nerve block is used for intraoperative and postoperative analgesia in nasal and oral surgery procedures, as well as in the chronic pain settings. Ultrasound guidance has not been described in the literature. The aim of the study was to assess the quality of ultrasound imaging of the infraorbital foramen and develop an “in-plane” technique of the block using a skull model.

Methods

The infraorbital foramina were assessed on five skull models immersed in the water bath. Ultrasound-guided simulation of an in-plane infraorbital nerve block was then performed. Slightly curved needle was placed close to the foramina and its visibility was recorded. Success rate and time to locate infraorbital foramina, success rate and time to insert the needle close to the foramina under ultrasound and correlation between the ultrasound and caliper measurements were evaluated and recorded. Data for the left and right foramen were compared.

Results

The infraorbital foramina were successfully located using ultrasound in all 20 cases. Simulation of infraorbital nerve block was also successful in all measurements. The time difference between locating or simulating blockade of the left and right infraorbital foramina was not statistically significant. Correlation between ultrasound measurement and direct measurement using a caliper was satisfactory for the distances between the inferior orbital rim and the inferior margin of the infraorbital foramen but poor for the distances between the lower rim of the orbit and the superior margin of the foramen.

Conclusions

This experimental study suggests that the infraorbital foramen is easily located using ultrasound and an “in-plane” ultrasound-guided technique for infraorbital nerve blockade is feasible on the model.     

Morphometric measurements from various reference points in the orbit of male Caucasians

The aim of this study was to determine the morphometric variations from various reference points to decrease risks in orbital surgery. Sixty-two orbits obtained from 31 skulls of male adult Caucasians were measured with a millimetric compass. On the medial orbital wall, the midpoint of the anterior lacrimal crest was the reference point; from this point we measured distances of 23.9Dž.3 mm, 35.6DŽ.3 mm, 41.7Dž.1 mm and 6.9ǃ.5 mm respectively to the anterior ethmoidal foramen, posterior ethmoidal foramen, midpoint of the medial aspect of the optic canal and posterior lacrimal crest. On the same wall, distances from the plane of the anterior and posterior ethmoidal foramina to the ethmoido-maxillary suture and distance from the posterior ethmoidal foramen to the anterior ethmoidal foramen and midpoint of the medial margin of the optic canal were 14.9DŽ.3 mm, 9.8DŽ.9 mm and 6.8DŽ.2 mm respectively. On the inferior orbital wall, the main reference point was the infraorbital foramen, and from this point to the midpoints of the lateral margin of the fossa for the lacrimal gland, inferior orbital fissure, inferior orbital rim and inferior aspect of the optic canal was 23.8lj.2 mm, 31.9Dž.9 mm, 6.7ǃ.9 mm and 50.3Dž.2 mm respectively. On the superior orbital wall, the distances from the supraorbital foramen to the midpoints of the superior orbital fissure, fossa for the lacrimal gland and superior aspect of the optic canal were 45.7Dž.6 mm, 26.0DŽ.5 mm and 45.3Dž.2 mm respectively. Furthermore, on the same wall, the distance from the posterior ethmoidal foramen to the midpoint of the superior orbital fissure was 14.6DŽ.8 mm. Finally, on the lateral orbital wall the frontozygomatic suture was the reference point. From this point distances to the midpoints of the fossa for the lacrimal gland, superior orbital fissure, lateral aspect of the optic canal and inferior orbital fissure were 17.5DŽ.1 mm, 37.7Dž.6 mm, 44.9DŽ.5 mm and 33.4Dž.1 mm respectively. The French version of this article is available in the form of electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00276-002-0071-0. Résumé. Le but de cette étude était de déterminer les variations morphométriques à partir de différents points de référence afin de diminuer le risque en chirurgie orbitaire. Soixante-deux orbites, obtenues à partir de 31 crânes de sujets mâles adultes caucasiens, ont été mesurées avec un compas millimétrique. Sur la paroi médiale de l'orbite le milieu de la crête lacrymale antérieure était le point de référence ; à partir de ce point ont été obtenues des mesures de 23,9Dž,3 mm, 35,6DŽ,3 mm, 41,7Dž,1 mm, 6,9ǃ,5 mm respectivement pour le foramen ethmoïdal antérieur, le foramen ethmoïdal postérieur, le milieu du bord médial du canal optique et la crête lacrymale postérieure. Sur cette même paroi, la distance entre le niveau des foramen ethmoïdaux antérieur et postérieur et la suture ethmoïdo-maxillaire, et la distance entre le foramen ethmoïdal postérieur et le milieu du bord médial du canal optique ont été trouvées à respectivement 14,9DŽ,3 mm, 9,8DŽ,9 mm, 6,8DŽ,2 mm. Sur la paroi inférieure de l'orbite, le principal point de référence était le foramen infra-orbitaire; à partir de ce point ont été mesurées respectivement les distances jusqu'aux milieux du bord latéral de la fosse de la glande lacrymale, de la fissure orbitaire inférieure, du bord orbitaire inférieur et du bord inférieur du canal optique respectivement à 23,8lj,2 mm, 31,9Dž,9 mm, 6,7ǃ,9 mm, 50,3Dž,2 mm. Sur la paroi supérieure de l'orbite, les distances à partir du foramen supra-orbitaire jusqu'aux milieux de la fissure orbitaire supérieure, de la fosse de la glande lacrymale et du bord supérieur du canal optique ont été trouvées respectivement à 45,7Dž,6 mm, 26,0DŽ,5 mm, 45,3Dž,2 mm. De plus, sur cette même paroi, la distance séparant le foramen ethmoïdal postérieur et le milieu de la fissure orbitaire supérieure a été mesurée à 14,6DŽ,8 mm. Pour terminer, sur la paroi latérale de l'orbite, la suture fronto-zygomatique était le point de référence. A partir de ce point, des mesures ont été réalisées jusqu'aux milieux de la fosse de la glande lacrymale, de la fissure orbitaire supérieure, du bord latéral du canal optique et de la fissure orbitaire inférieure, trouvées respectivement à 17,5DŽ,1 mm, 37,7Dž,6 mm, 44,9DŽ,5 mm et 33,4Dž,1 mm.     

眶下孔相关径线测量及定位研究

目的　测量完整人颅骨的眶下孔的相关径线,为临床应用提供数据。 方法　用游标卡尺测量60例（120侧）成人眶下孔内径的长径和短径,并观察孔的形状,观察副孔的数量。测量眶下孔到眶下缘的距离,切此线与面部前正中线平行。测量眶下孔到梨状孔外缘的距离,切此线与面部前正中线垂直。 结果　① 眶下孔为圆孔（10%）和椭圆形孔（90%）;②左右两侧眶下孔副孔总的出现率为2.5%。③眶下孔的长径为（4.24±0.91）mm（2.48~7.59 mm）。④眶下孔的短径为（2.55±0.48）mm（1.37~3.63 mm）。⑤眶下孔到眶下缘的距离为（8.54±1.60）mm（5.16~13.63 mm）。⑥眶下孔到梨状孔外缘的距离为（16.55±2.01）mm（11.73~23.17 mm）。 结论　完善人颅骨眶下孔的形态学资料,为临床开展眶下孔的应用研究提供数据。     

The Localization of the Supraorbital Notch or Foramen is Crucial for Headache and Supraorbital Neuralgia Avoiding and Treatment

The aim of this study was to provide the morphological and morphometric data of the supraorbital foramina or notches related to sex, side, and the climatic conditions where the population lived. It was hypothesized that the distribution of the occurrence and location of these openings depends on climatic conditions in which the population lived. Orbits from 866 dried skulls obtained from three climatic regions: warm, temperate, and cold were examined. The examination concentrated on the configuration (notch/foramen) and on the distances to the reference points: nasion, frontomalare orbitale, infraorbital foramen and the superior orbital rim. In 14.3% of cases a smooth supraorbital rim was observed while different variants of the structures were observed in 85.7% of the cases. In cold climatic conditions, supraorbital foramina were found in the highest frequency (35.4%). In warm and temperate climates, the observed frequencies of supraorbital foramen were the lowest (18.8% and 19.9%, respectively). Frequency of supraorbital notches was the lowest of those skulls from a cold climate (44.0%) and the highest in those from a warm climate (59.0%). These results support the hypothesis that the occurrence of the supraorbital notches is greater in populations from warm compared with cold regions. This would provide a greater exit route for the neurovascular bundle and this may be related to the thermoregulatory processes in the supraorbital region. Furthermore, knowledge of precise locations of supraorbital structures is important when a supraorbital nerve block is given, for example, in the treatment of migraine headaches. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Morphometric analysis of the infraorbital groove, canal, and foramen on three-dimensional reconstruction of computed tomography scans

Purpose

This study aimed to investigate the anatomy of the infraorbital foramen (IOF), infraorbital canal (IOC), and infraorbital groove (IOG) with regard to surgical and invasive procedures using three-dimensional reconstruction of CT scans.

Methods

The CT scans of 100 patients were evaluated retrospectively. The morphology of the IOF, IOC, and IOG as well as their relationships to different anatomic landmarks was assessed in a three-dimensional model.

Results

The mean length of the IOC and IOG and the angle of the IOC relative to IOG were 11.7 ± 1.9, 16.7 ± 2.4 mm, and 145.5° ± 8.5°, respectively. The mean angles of the IOC relative to vertical and horizontal planes were 13.2° ± 6.4° and 46.7° ± 7.6°, respectively. In the relationships between the IOF and different anatomic landmarks, the mean distances from the IOF to supraorbital notch/foramen, facial midline, and infraorbital rim were 5.6 ± 3.1 mm laterally, 26.5 ± 1.9 mm laterally, and 9.6 ± 1.7 mm inferiorly, respectively. The mean distance from the IOF to anterior nasal spine (ANS) was 35.0 ± 2.6 mm, and the mean angle of the axis that passed the IOF and ANS relative to horizontal plane was 28.8° ± 4.1°. In addition, the mean soft tissue thickness overlying the IOF was 11.4 ± 1.9 mm.

Conclusions

These results provide detailed knowledge of the anatomical characteristics and clinical importance of the IOF. Such knowledge is of paramount importance for surgeons when performing maxillofacial surgery and regional block anesthesia.     

Anatomical study of the infraorbital foramen

Detailed knowledge of variations of the infraorbital foramen (IOF) and the establishment of a constant reference point for needle insertion are important for safe and successful regional block and for avoiding iatrogenic injury to the nerve during surgery in the midfacial region. Infraorbital foramina from 133 sides of 67 dry intact adult skulls of undetermined gender were examined for variations in shape, number, location in relation to bony landmarks, and relationship to the maxillary teeth. The angles of needle insertion in the sagittal and Frankfurt planes were determined. The infraorbital foramina were located at an average distance of 6.33 ± 1.39 mm below the infraorbital margin, 25.69 ± 2.37 mm from the median plane, 15.19 ± 1.70 mm from the lateral margin of the piriform aperture, and 28.41 ± 2.82 mm above the maxillary alveolar border. The average angles of needle insertion through the IOF with the sagittal and Frankfurt planes were 21.14° ± 10.10° and 31.79° ± 7.68°, respectively. Multiple foramina were found in 21% of the hemi‐skulls. The foramen was less than 2 mm in size in 23.31% of the hemi‐skulls. The position of the IOF with respect to the maxillary teeth varied from the interval between the canine and first premolar to the first molar, but in half of the specimens it lay in line with the second maxillary premolar tooth. The observations made in this study should be useful for planning infraorbital nerve block or surgery around the IOF. Clin. Anat. 28:753–760, 2015. © 2015 Wiley Periodicals, Inc.     

The relationship between accessory foramina and tumour spread on the medial mandibular surface

The medial cortical surface of the mandible can be involved by tumour infiltration from the floor of the mouth. A detailed study of spread via accessory foramina through the edentulous alveolar crest has been previously undertaken, but no similar study has been carried out for the medial surface. In order to gain further appreciation of the mode of tumour spread, a study of the number and distribution of accessory foramina on the medial mandibular surface was performed on 89 mandibles. The number of foramina varied greatly from specimen to specimen. In the ascending ramus above the inferior dental foramen, 3 mandibles showed no foramina; the condylar section possessed the greatest proportion followed by the sigmoid and the coronoid. On the rest of the medial surface below the inferior dental foramen, all specimens showed at least 1 accessory foramen; the greatest concentration was in the middle third along the path of the inferior dental canal, followed by the upper third and the lower third section. Accessory foramina were repeatedly present at certain dedicated sites. The medial facing wall of the inferior dental foramen was found to be the commonest dedicated site (98.3%) followed by foramina on either side of the genial tubercles (71.9%), the digastric fossa (71.9%) and the median foramen above the genial tubercles (64%). The findings of this study are in keeping with the current observation that the lower border is least commonly involved in tumour spread. In view of the presence of accessory foramina along the inferior dental canal and especially on the medial facing wall of the inferior dental foramen, it is imperative to preclude tumour spread in this region prior to undertaking the conservative rim resection procedure. Medial to the symphysis the alveolar mucosa dips down almost to the level of the dedicated foramina in the vicinity of the genial tubercles. As a general rule the attached muscle forms a barrier to tumour spread except in the later stages, however, in irradiated mandibles resistance to spread has been previously reported to be diminished. Under these circumstances, it is possible that the numerous accessory foramina reported in this study could facilitate a direct pathway into the cancellous bone.     

Anatomical Consideration of the Anterior and Lateral Cutaneous Nerves in the Scalp

To better understand the anatomic location of scalp nerves involved in various neurosurgical procedures, including awake surgery and neuropathic pain control, a total of 30 anterolateral scalp cutaneous nerves were examined in Korean adult cadavers. The dissection was performed from the distal to the proximal aspects of the nerve. Considering the external bony landmarks, each reference point was defined for all measurements. The supraorbital nerve arose from the supraorbital notch or supraorbital foramen 29 mm lateral to the midline (range, 25-33 mm) and 5 mm below the supraorbital upper margin (range, 4-6 mm). The supratrochlear nerve exited from the orbital rim 16 mm lateral to the midline (range, 12-21 mm) and 7 mm below the supraorbital upper margin (range, 6-9 mm). The zygomaticotemporal nerve pierced the deep temporalis fascia 10 mm posterior to the frontozygomatic suture (range, 7-13 mm) and 22 mm above the upper margin of the zygomatic arch (range, 15-27 mm). In addition, three types of zygomaticotemporal nerve branches were found. Considering the superficial temporal artery, the auriculotemporal nerve was mostly located superficial or posterior to the artery (80%). There were no significant differences between the right and left sides or based on gender (P>0.05). These data can be applied to many neurosurgical diagnostic or therapeutic procedures related to anterolateral scalp cutaneous nerve.     

The ZMF: Is it a reliable intraoperative guide for the IOF?

Intraoperative localization of the inferior orbital fissure (IOF) is necessary when making an osteotomy across the zygomatic bone while performing an orbito‐zygomatic craniotomy. The zygomatico‐facial foramen (ZMF) may serve as good reference point for locating the IOF. In this study, the position of the ZMF was assessed and its location in relation to the IOF was measured in 78 skulls. The ZMF was present in 83.3% of the skulls and when present, was related to the lateral end of the IOF in all cases. The mean distance of the ZMF from the IOF was 15.6 mm, and the mean distance between the ZMF and the fronto‐zygomatic suture was 25.9 mm. In skulls where the ZMF was absent, the mean distance of the inferior orbital rim (at the level of IOF) from the fronto‐zygomatic suture (20.7 mm) could be used for determining the position of the IOF. The IOF could thus be located ～15–16 mm medial to the ZMF in the same transverse plane. The location of the ZMF could also be used as a landmark for determining the inferior limit of the orbito‐zygomatic craniotomy. Clin. Anat. 22:451–455, 2009. © 2009 Wiley‐Liss, Inc.     

Regional thickness of facial skin and superficial fat: Application to the minimally invasive procedures

Various recently introduced minimally invasive treatment modalities are now widely used for enhancing the aging face. In a special, filler is used to increase the volume of tissue, and so understanding the regional thickness and distribution of the facial superficial fat is essential for optimizing minimally invasive procedures. The aim of this study was to establish the overall facial skin and superficial fat thicknesses using a three‐dimensional (3D) scanning system. From 53 adult Korean and Thai embalmed adult cadavers, the undissected and serially‐dissected facial specimens were scanned and reconstructed. The facial skin and superficial fat thicknesses on seven facial regions were calculated from the superimposed images. The facial skin tended to become thicker in the order of the radix and dorsum, and the temple, supraorbital, forehead, perioral, cheek, and infraorbital areas. The skin was thinnest at radix and dorsum (1.51 ± 0.55 mm), and thickest in infraorbital region (1.97 ± 0.84 mm). The facial superficial fat thickness tended to increase in the order of the radix and dorsum, supraorbital, forehead, temple, cheek, infraorbital, and perioral regions. The superficial fat was thinnest at the radix and dorsum (1.61 ± 1.07 mm), and thickest in the perioral region (5.14 ± 3.31 mm). The facial superficial fat thickness tended to increase in the order of the radix and dorsum, supraorbital, forehead, temple, cheek, infraorbital, and perioral regions. The present findings indicate that 3D scanning system can yield crucial anatomical information about depths of the facial skin and superficial fat layers for utilization in various clinical procedures. Clin. Anat. 32:1008–1018, 2019. © 2019 Wiley Periodicals, Inc.     

下颌骨的显微解剖学特征及其临床意义

目的：探讨口腔肿瘤向下颌骨浸润蔓延的传播扩散途径(模式)以及在微创术中保留下颌骨的可行性。方法：将60例成人下颌骨以染料浸泡后，在10～20倍的体视显微镜下进行观察。结果：在经染料浸泡的标本上，渗入着色剂的副孔清晰可见。下颌骨内侧面着色副孔的出现率比外侧面的多；在外侧面，下区上部的着色副孔数最多；在内侧面，下区中部的着色副孔数最多。结论：口腔肿瘤向下颌骨的浸润蔓延可能有3种传播扩散途径：(1)口腔肿瘤经下颌骨外侧面的副孔向下颌骨浸润扩散；(2)口腔肿瘤经下颌骨内侧面的副孔向下颌骨浸润扩散；(3)口腔肿瘤一旦侵及骨髓腔，便可在下颌骨内经下颌管迅速传播扩散至其它部位。     

Incidence and morphological study of zygomaticofacial and zygomatico-orbital foramina in dry adult human skulls: the non-metrical variants

Morphological diversity in the form of multiple zygomaticofacial (ZF) foramina was studied in 165 dry, unsexed adult human skulls. Zygomatic bones revealed variation in the number of foramina on their orbital and facial aspects. These were absent in 72 (21.8%) sides. A single ZF foramen was seen in 148 (44.9%) sides. Two ZF foramina were found in 92 (27.9%) sides, out of which 29 (8.8%) sides had one zygomatico-orbital (ZO) foramen, while 63 (19.1%) sides had two ZO foramina. Three ZF foramina, a relatively uncommon occurrence, were found in 17 (5.1%) sides, which included eight (2.4%) sides with one less and nine (2.7%) sides with the same number of ZO foramina. Four ZF foramina were seen in one (0.3%) side with three on the orbital aspect, a feature not reported before. The zygomatic nerve may be disrupted on elevating periorbita from the lateral wall during orbital surgery, and care should be taken to prevent injury to the nerve during the lateral orbitotomy approach to access intraorbital soft tissue tumors.     

Anatomical localization of submandibular gland for botulinum toxin injection

The aim of this study was to document the anatomical landmarks of the submandibular gland (SMG) for a botulinum toxin injection. Thirty-four SMGs from 20 cadavers were examined. The mean length of a reference line between the angle of the mandible and the gnathion was 94.8 ± 5.9 mm, the proximal and distal point of the SMG from the angle of the mandible was 10.6% (11.5 ± 3.5 mm) and 41.8% (40.9 ± 5.2 mm), respectively. The facial artery came out of the SMG at 11.6% (14.6 ± 3.4 mm) and the position of the intersection of the facial artery with the inferior border of the mandible was located at 24.4% (28.0 ± 5.5 mm) from the angle of the mandible. The shape of the SMG was generally triangular or irregular round on the anatomical position. The mean superior–inferior diameter, anterior–posterior diameter and medial–lateral diameter of the gland was 28.8 ± 4.1, 30.0 ± 6.1 and 15.1 ± 3.5 mm, respectively. The safety zone for the injection was 20–35% from the mandible angle on the inferior view and 1.5 cm below the inferior line of the mandible on the lateral view. In addition, the needle should be inserted to a depth of 2.0 cm from the skin surface on the inferior view. These results may assist in determining a accurate localization of injection sites for the SMG, particularly for injections without ultrasound guidance.