Anatomical study of the supraorbital and supratrochlear nerves: A new classification and application to understanding some migraine headaches

The frontal nerve is the largest branch of the ophthalmic nerve. This nerve gives rise to two terminal branches, the supraorbital (SON) and supratrochlear nerves (STN). To the best of our knowledge, there are no reports describing the detailed proximal course of these nerves while inside the orbit. Therefore, the goal of this study was to clarify the anatomy of the SON and STN inside and at their exit from the orbit. Twenty sides from ten fresh-frozen cadavers were used in this study. Intra and extra orbital dissections were performed to observe the course of the SON and STN. Additionally, measurements of the nerves were made at these locations. The course of the SON and STN inside the orbit was classified into three groups depending on the STN branching pattern from the SON. The group without any branch from the SON and STN inside the orbit was the most common. The exit points of these nerves were via the supraorbital notch, foramen, or neither a notch nor foramen. A distinct fibrous band was consistently found tethering the nerve except in specimens with nerves traversing a bony foramen. The mean diameters of the SON and STN were 1.3 ± 0.2 and 0.7 ± 0.1 mm, respectively. The results of this study further our knowledge of the course and morphology of the SON and STN and might be useful for better understanding and potentially treating some forms of migraine headache due to SON or STN compression/entrapment. Clin. Anat. 33:332–337, 2020. © 2019 Wiley Periodicals, Inc.     

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.     

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.     

Embryonic anastomosis between hypoglossal nerves

This article presents two cases of anastomosis of hypoglossal nerves in the suprahyoid region in human embryos of CR length 10.75 and 17.5 mm. This variation was studied in two human specimens at this stage of development and compared with the normal arrangement of the hypoglossal nerves in embryos at the same stage. The anastomotic branches were of similar caliber to the main trunks. In both cases the anastomosis was located dorsal to the origin of the geniohyoid muscles and caudal to the genioglossus muscles, lying transversally over the cranial face of the body of the hyoid bone anlage. The anastomosis formed a suprahyoid nerve chiasm on the midline in the embryo of 10.75 mm CR length.     

A cadaver study to determine the minimum volume of methylene blue or black naphthol required to completely color the nerves relevant for anesthesia during breast surgery

Regional anesthesia for breast surgery may require a large amount of local anesthetic solution to provide an adequate blockade of all relevant structures. The purpose of this study was to determine the minimal volume of fluid required to anesthetize all nerves to adequately provide anesthesia for breast surgery. This is an open randomized study. Cadavers were embalmed using Thiel's technique and were injected with different volumes of 0.2% methylene blue or 0.2% black naphthol for a superficial cervical plexus block (2, 5, 10, or 15 mL), an interscalene block (5, 10, 15, or 20 mL), paravertebral blocks from C(8) to T(6), and intercostal nerve blocks at 8 cm from the midline (2 or 3 mL) under ultrasound-guided or assisted techniques. The following minimal volumes of fluid were required for complete coloration of the nerves: 2 mL for the supraclavicular nerves; 20 mL for the nerve roots from C(5) to C(7), inclusive, if intraneural injection was avoided; 3 mL per root for the nerve roots from C(8) to T(6), inclusive, for a paravertebral block; and 2 mL per nerve for intercostal nerve blocks at T(4) and lower. With 20 mL of solution at the interscalene level, the roots of C(3) and C(4) were also colored; therefore, a separate injection for the supraclavicular nerves was unnecessary. We conclude that regional anesthesia for complex breast surgery can be achieved with a volume of local anesthetic as low as 41 mL.     

人膈肌内神经分支分布

目的：探讨人膈的神经支配和肌内神经分支分布特点。方法：改良Sihler’s肌内神经分支染色法。结果：(1)一侧膈神经入肌后一般分为3—4支(3支型4例,4支型2例),1支(前支)向前内侧走行,支配胸部,1～2支(前外侧支)向外侧走行,支配肋部,最后1支(后支)最粗大,向后下走行,分为后外侧支和后脚支,分别支配膈中心腱外侧叶后外侧的肋部和腰部,各级神经的分支在肌束中部密集排列成神经丛。(2)6例标本均未发现左侧或右侧膈神经越过中线至对侧。(3)2例带肋间肌的标本肉眼未见有肋间神经分支进入膈。结论：(1)左、右膈神经分布于膈,未见左右侧膈神经重叠支配和优势支配。(2)膈神经的终末分支在肌束中部密集排列形成似“肾形”的神经丛带。     

上肢神经肌支的显微解剖及其在痉挛性瘫痪治疗中的意义

目的：为寻求解除上肢痉挛性瘫痪的新途径提供理论依据。方法：在手术显微镜下,对43例成人上肢标本解剖观测,了解痉挛性脑瘫所致上肢痉挛性屈肘,旋前和屈腕畸形的主动肌神经肌支的来源,直径,可分离长度及发出部位。结果：肱二头肌肌支平均2．72支,来源于肌皮神经（97．5％）和正中神经（2．5％）,肱肌肌支平均2．74支,来源肌皮神经（80．5％）,其余分别来源于桡神经（15．3％）,正中神经（4．2％）,肱桡肌肌支平均1．77支,来源于桡神经,旋前圆肌肌支平均2．33支,来源于正中神经;尺侧腕屈肌肌支平均1．72支,来源于尺神经,它们的可分离长度分别为：肱二头肌肌支23．94mm,肱肌肌支21．63mm,肱桡肌肌支21．38mm,旋前圆肌肌支27．27mm,尺侧腕屈肌肌支21．70mm,神经肌支的横径分别为：0．99,1．00,0．86,0．84,0．83mm,在起始与进入肌门处的横径比较（t)检验无显著性差异（P＞0．05）。结论：神经肌支的横径考虑与神经所含数量有关,术中可在志始处选择性切断,切除的长度以术后不再出现神经再连续为度。     

Anatomy of the ilioinguinal and iliohypogastric nerves with observations of their spinal nerve contributions

Proper anesthesia and knowledge of the anatomical location of the iliohypogastric and ilioinguinal nerves is important during hernia repair and other surgical procedures. Surgical complications have also implicated these nerves, emphasizing the importance of the development of a clear topographical map for use in their identification. The aim of this study was to explore anatomical variations in the iliohypogastric and ilioinguinal nerves and relate this information to clinical situations. One hundred adult formalin fixed cadavers were dissected resulting in 200 iliohypogastric and ilioinguinal nerve specimens. Each nerve was analyzed for spinal nerve contribution and classified accordingly. All nerves were documented where they entered the abdominal wall with this point being measured in relation to the anterior superior iliac spine (ASIS). The linear course of each nerve was followed, and its lateral distance from the midline at termination was measured. The ilioinguinal nerve originated from L1 in 130 specimens (65%), from T12 and L1 in 28 (14%), from L1 and L2 in 22 (11%), and from L2 and L3 in 20 (10%). The nerve entered the abdominal wall 2.8 ± 1.1 cm medial and 4 ± 1.2 cm inferior to the ASIS and terminated 3 ± 0.5 cm lateral to the midline. The iliohypogastric nerve originated from T12 on 14 sides (7%), from T12 and L1 in 28 (14%), from L1 in 20 (10%), and from T11 and T12 in 12 (6%). The nerve entered the abdominal wall 2.8 ± 1.3 cm medial and 1.4 ± 1.2 cm inferior to the ASIS and terminated 4 ± 1.3 cm lateral to the midline. For both nerves, the distance between the ASIS and the midline was 12.2 ± 1.1 cm. To reduce nerve damage and provide sufficient anesthetic for nerve block during surgical procedures, the precise anatomical location and spinal nerve contributions of the iliohypogastric and ilioinguinal nerves need to be considered.     

吻合指神经的指动脉逆行岛状皮瓣修复指腹缺损

目的：报道吻合指神经的指动脉逆行岛状皮瓣修复指腹缺损的解剖学基础及其临床应用。方法：对20具成人尸体40例手的指掌侧固有神经直径和分支进行了测量；并对39例患者的39指指腹缺损行吻合指掌侧固有神经的指动脉逆行岛皮瓣修复术。结果：（1）指掌侧固有神经平近节指横纹处理1．4－2．0mm，厚0．8－1．0mm；平末节指横纹处宽1．0－1．4mm，厚0．6－0．8mm。（2）近节掌侧支为4．4－5．3支，背侧支为3．8－4．0支；中节掌侧支为3．5－4．6支，背侧支为3．4－4．1支；末节终支为3．8－4．6支。（3）39例患指中38例一期成活，指腹饱满，外观理想，耐磨性好，两点辨别觉达5mm内，指腹感觉达S3以上。结论：吻合指神经的指动脉逆行岛状皮瓣修复指腹缺损，优于未吻合神经的术式。     

Intercostal nerves block for mastectomy in two patients with advanced breast malignancy

Regional anesthesia is recognized as an alternative to general anesthesia for modern breast cancer surgery. Various techniques of block have been described. Each has its unique problems. Regional anesthesia was chosen for simple mastectomy in two patients with advanced breast malignancy, due to compromised pulmonary status resulting from widespread malignant infiltration of both lungs. We used intercostal nerves block. The block was supplemented with an infraclavicular infiltration to interrupt the branches of the superficial cervical plexus that provide sensation to the upper chest wall and subcutaneous infiltration in the midline to block the nerve supply from the contralateral side. Anesthesia was generally effective and the operations were uneventful. Both patients and surgeons expressed satisfaction. We conclude that where patients have significant comorbidities that make general anesthesia undesirable, the use of intercostal nerves block remains a safe and reliable anesthetic option that allows the patient access to surgery for simple mastectomy.     

Anatomic variation of the spinal origins of lateral and medial pectoral nerves

Lateral and medial pectoral nerves are distributed to the pectoralis major and minor muscles. The purpose of this study was to identify the spinal origins of lateral and medial pectoral nerves and to evaluate the participating amounts of each spinal nerve composing both pectoral nerves. Two types of spinal origins appeared in lateral pectoral nerves. The first type was composed of nerve fibers from C5, C6, and C7 with a frequency of 50.0% and the second type was composed of nerve fibers from C6 and C7 at a frequency of 50.0%. Regarding the average participating diameter to the lateral pectoral nerve, C7 was the thickest with a value of 1.60 +/- 0.35 mm (mean +/- SD), next was C6 at 0.83 +/- 0.18 mm, and C5 was the third at 0.42 +/- 0.24 mm. Three types of spinal origin appeared in the medial pectoral nerve. The first type was comprised of nerve fibers from C8 and T1 in 73.3% of cases. The second type was comprised of C8 only in 23.4% of cases, and the third type was comprised of T1 only in 3.3% of cases. The average participating diameter was 0.71 +/- 0.22 mm from C8 and 0.52 +/- 0.17 mm from T1. These results show that the spinal origins of the both pectoral nerves were various. Participating amounts of the lateral pectoral nerve appeared sequentially in the order of C7, C6, and C5. In the medial pectoral nerve, C8 participated more amounts than T1.     

Size and separability of the calcaneal and the medial and lateral plantar nerves in the distal tibial nerve

The tibial nerve (TN) has three main terminal branches: the medial and lateral plantar nerves and the calcaneal branch (CB), which innervates the foot sole. The design and implantation of nerve cuff electrodes with separate channels for each of these three terminal branches would provide significant sensory information, which can be used in functional electrical stimulation systems to assist standing or to correct foot drop. Detailed quantitative anatomical data about fascicular size and separability of the terminal branches of TN are needed for the design and implantation of such cuff electrodes. Therefore, the branching pattern, the fascicular separability and the fascicular size of the TN posterior to the medial malleolar-calcaneal axis were examined in this study, using ten human TN specimens. The TN branching patterns were highly dispersed. For the CBs, multiple branches were identified in five (50%) of the specimens. For the TN, the bifurcation point was located within the tarsal tunnel in eight (80%) of the cases. The distance proximal to the medial malleolar-calcaneal axis for which the TN could be split ranged form 0 to 41 mm. Quantitative and qualitative data were obtained for the fascicular size and separability of the TN. Only the CB of the TN proved separable for a sufficient length for nerve cuff electrode implantation. The results suggest the use of a two-channel cuff with one common channel for the lateral and medial plantar nerves, having multiple electrodes for selective recording, and one channel for the CB.     

Landmarks for the identification of the cutaneous nerves of the occiput and nuchal regions

Although surgical procedures are often performed over the posterior head and neck, surgical landmarks for avoiding the cutaneous nerves in this region are surprisingly lacking in the literature. Twelve adult cadaveric specimens underwent dissection of the cutaneous nerves overlying the posterior head and neck, and mensuration was made between these structures and easily identifiable surrounding bony landmarks. All specimens were found to have a third occipital nerve (TON), lesser occipital nerve (LON), and greater occipital nerve (GON), and we found that the TON was, on average, 3 mm lateral to the external occipital protuberance (EOP). Small branches were found to cross the midline and communicate with the contralateral TON inferior to the EOP in the majority of sides. The mean diameter of the main TON trunk was 1.3 mm. This trunk became subcutaneous at a mean of 6 cm inferior to the EOP. The GON was found to lie at a mean distance of 4 cm lateral to the EOP. On all but three sides, a small medial branch was found that ran medially from the GON to the TON approximately 1 cm superior to a horizontal line drawn through the EOP. The GON was found to pierce the semispinalis capitis muscle on average 2 cm superior to the intermastoid line. The mean diameter of the GON was 3.5 mm. The GON was found to branch into medial and lateral branches on average 0.5 cm superior to the EOP. The LON was found to branch into a medial and lateral component at approximately the midpoint between a horizontal line drawn through the EOP and the intermastoid line. The main LON trunk was found on average 7 cm lateral to the EOP. In specimens with a mastoid branch of the great auricular nerve (GAN), this branch was found at a mean of 9 cm lateral to the EOP. The main trunk of this branch of the GAN was found to lie on average 1 cm superior to the mastoid tip. Easily identifiable bony landmarks for identification of the cutaneous nerves over the posterior head and neck can aid the surgeon in more precisely identifying these structures and avoiding complications. Although the occipital nerves were found to freely communicate with one another, avoiding the main nerve trunks could lessen postoperative or postprocedural morbidity. Moreover, clinicians who need to localize the occipital nerves for the treatment of occipital neuralgia could do so more reliably with better external landmarks.     

Peripheral development of avian trigeminal nerves

Development of the trigeminal nerve branches was studied in stage -17 to -27 chick embryos stained with an antibody to neurofilament protein. The following findings were obtained. (1) Ectopic ganglia transiently appeared in the ectoderm of the supraorbital region and were considered as remnant ophthalmic-placode-derived ganglia. (2) Most of the cutaneous sensory branches of the maxillomandibular nerve arose from a loosely arborized mass of neurites, provisionally termed the maxillomandibular reticulum, in which the fibers intermingled in a seemingly random fashion. (3) The growth of the trigeminal branches was mainly correlated with the development of the facial processes; however, irregular communications between different groups of branches were observed, suggesting that topographical organization of the peripheral branches is not rigid in early stages. (4) From the ophthalmic nerve around stage 23, transient dorsal rami developed and were distributed in the mesenchymal space, the cavum epiptericum, and passed near the ectoderm. Their homology with the rr. tentorii in human anatomy is suggested.     

内镜经眉弓上锁孔入路的解剖学研究

目的 探索内镜经眉弓上锁孔入路暴露颅底中线区域的解剖结构,为临床该术式切除颅底中线区域肿瘤提供解剖学基础。 方法 内镜经眉弓上锁孔入路解剖5具成人尸头标本,观察该入路暴露的颅底中线区域脑组织、血管及神经。 结果 内镜经眉弓上锁孔入路可充分暴露前床突及其内侧前颅底硬脑膜、嗅沟及嗅神经;蝶鞍区可显露视神经、视交叉、视交叉前间隙、垂体上动脉、眼动脉、颈内动脉及其周围间隙;上斜坡区域可显露鞍背硬脑膜、乳头体、基底动脉末端、小脑上动脉、大脑后动脉、后交通动脉、动眼神经、滑车神经、三叉神经、面神经、前庭蜗神经及脑桥腹侧。 结论 内镜经眉弓上锁孔入路切除颅底中线区域肿瘤在解剖学上可行,临床上可作为常规显微镜手术及经鼻内镜入路手术的有效补充。     

The course, relations and distribution of the inferior alveolar nerve and its branches in the cat

The course, relations and distribution of the inferior alveolar nerve and its branches in the cat are described. The nerves have been studied by dissection, histologically and by using electrophysiological techniques. Dissection revealed a basic pattern on which some individual variation was superimposed. The inferior alveolar nerve has three branches supplying the alveolar process (alveolar branches), one branch supplying the canine and incisor region (canine/incisor branch) and four mental branches (posterior, main and 2 anterior). Fibres supplying the teeth were found in all except the mental branches. Pulpal, periodontal and buccal gingival margin fibres from an individual tooth generally travelled together, but often in more than one branch. Branched axons supplying both tooth pulp and an area of mental skin were found. The axons branched at the point of separation of the appropriate mental nerve from the main trunk. A cutaneous midline overlap of 1-2 mm was found, but there was no transmedian innervation of tooth pulps.     

Discussion of clinical anatomy of the lingual nerves

The tongue has various functions, such as gustation, pronunciation, mastication, and deglutition. The nerve fibers are complexly intermingled, and communications between the lingual nerve and the hypoglossal nerve have been reported. Fifteen Japanese heads (30 sides) donated to the 2nd-year students dissection course at the Nippon Dental University School of Life Dentistry, Niigata, were studied with regard to the following aspects: 1. relation of the bifurcation between the lingual and the inferior alveolar nerves close to the oval foramen; 2. distance between the oral foramen and the bifurcation of the lingual and inferior alveolar nerves; and 3. communication between the lingual and hypoglossal nerves. Three types of bifurcation were observed. The standard bifurcation was observed in 21 cases (70.1%). A high bifurcation was observed in 5 cases (16.6%), and a communicating bifurcation was observed in 4 cases (13.3%). The average distance between the oval foramen and the bifurcation of the lingual and inferior alveolar nerves was 8.7 +/- 4.2 mm (minimum: 0 mm/maximum: 14 mm). An anterior-type communication between the lingual and hypoglossal nerves was observed in 8 cases (26.6%), a posterior-type was observed in 17 cases (56.7%), and no communication was observed in 5 cases (17.7%).     

Differentiation of the anterior body wall and truncal epidermis and associated co-migration of cutaneous nerves and mesenchyme

The present study examines the relationship between the migration of mesenchyme and associated cutaneous nerves that are involved in the closure of the anterior body wall in embryonic mice and rats by light and electron microscopy. The sternum is formed by the migration of condensations of mesenchyme originating in the dorsolateral body wall known as sternal bands. In the course of analyzing this process in rodent embryos we have identified similar paired caudal extensions of the sternal bands that are responsible for the closure of the abdominal wall following resolution of the umbilical hernia, and we suggest these bands of mesoderm should be referred to as the abdominal bands. Both the sternal and abdominal bands are associated with the development of the segmental spinal nerves and their cutaneous terminal branches. The first cutaneous nerve to reach the skin surface in rats is the later cutaneous nerve (LCN) at E13.0 days followed by the posterior and anterior cutaneous nerves (PCN and ACN) at E13.5 days. The ACN co-migrates with the sternal and abdominal bands, and terminal branches of axons from the ACN approach the epidermis during this migration. Differentiation of the epidermis could be recognized as a change in shape of epidermal cells from squamous to cuboidal, and this initial differentiation coincides with the onset of cutaneous innervation, beginning at the site of the LCN and following the extent of innervation of the PCN as well as the migration of the mesodermal bands and associated ACN. The paired ACN's meet in the ventral midline at E16.5 in rats as the sternal bands fuse, and terminal axons from both nerves densely innervate the midline skin. The wave of cutaneous differentiation in the trunk is associated with the onset of cutaneous innervation, and this process is associated with the co-migration of bands of mesoderm that close the anterior body wall.     

A review of the thoracic splanchnic nerves and celiac ganglia

Anatomical variation of the thoracic splanchnic nerves is as diverse as any structure in the body. Thoracic splanchnic nerves are derived from medial branches of the lower seven thoracic sympathetic ganglia, with the greater splanchnic nerve comprising the more cranial contributions, the lesser the middle branches, and the least splanchnic nerve usually T11 and/or T12. Much of the early anatomical research of the thoracic splanchnic nerves revolved around elucidating the nerve root level contributing to each of these nerves. The celiac plexus is a major interchange for autonomic fibers, receiving many of the thoracic splanchnic nerve fibers as they course toward the organs of the abdomen. The location of the celiac ganglia are usually described in relation to surrounding structures, and also show variation in size and general morphology. Clinically, the thoracic splanchnic nerves and celiac ganglia play a major role in pain management for upper abdominal disorders, particularly chronic pancreatitis and pancreatic cancer. Splanchnicectomy has been a treatment option since Mallet‐Guy became a major proponent of the procedure in the 1940s. Splanchnic nerve dissection and thermocoagulation are two common derivatives of splanchnicectomy that are commonly used today. Celiac plexus block is also a treatment option to compliment splanchnicectomy in pain management. Endoscopic ultrasonography (EUS)‐guided celiac injection and percutaneous methods of celiac plexus block have been heavily studied and are two important methods used today. For both splanchnicectomies and celiac plexus block, the innovation of ultrasonographic imaging technology has improved efficacy and accuracy of these procedures and continues to make pain management for these diseases more successful. Clin. Anat. 23:512–522, 2010. © 2010 Wiley‐Liss, Inc.