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The facial muscles have significant roles for vocalization, feeding, and facial expression in both human and non-human primates. Of these, the anatomy of the incisivus labii superioris (ILS) and incisivus labii inferioris (ILI), which are considered as the accessory bundle of the orbicularis oris (OO) in humans, has rarely been documented in the literature. Our current understanding of the function of the ILS and ILI is that they probably retract the upper and lower lips. Also, there is no account of these muscles in non-human primates in the current literature. The aim of this study was to reveal the ILS and ILI in non-human primates. Five Macaca fascicularis, one Macaca fuscata, one Macaca fuscata yakui, and one Pan troglodytes were dissected. Seven formalin-fixed cadavers and one fresh cadaver were included. Both the ILS and ILI were observed in all specimens. The ILS originated from the incisive fossa of the maxilla and inserted into the OO. The mentalis (MT) and ILI arose from the incisive fossa of the mandible and inserted into the OO and the skin of the chin area. The MT and ILI in the P. troglodytes examined were thicker than in the other three non-human species, and the ILS and ILI in the three macaques were similar in shape to those of humans. The difference of these muscles may result in different functions of the lip such as during vocalization, feeding, and facial expression.

The bifid mandibular canal (BMC) is an anatomical variant of the mandible that is often observed on cone-beam computed tomographic images. We identified a BMC during routine cadaveric dissection. The upper mandibular canal contained the inferior alveolar nerve and artery, and the lower mandibular canal contained a large inferior alveolar vein. This latter vein left the mandible through a lateral lingual foramen and joined the anterior jugular vein. Additionally, this vein gave rise to small tributaries to the mental foramen and anterior surface of the mandible from the second mandibular canal. To our knowledge, this is the first report illustrating the contents of a BMC and drainage of a vein into the large anterior jugular vein.

We encountered a case of retroaortic left renal vein (RLRV) during an anatomical dissection course at our medical school in 2017. The case was a female cadaver who was 88 years old at death. Six roots of the left renal vein (RV) arose from the hilus of the kidney and joined to form one left renal vein, crossed dorsal to the abdominal aorta (AA) at the level of the second lumbar vertebra, and then drained into the inferior vena cava (IVC). Two roots joined at the right renal hilus to become the right RV to then drain into the IVC at the level of the first lumbar vertebral body. The reported frequency of RLRV is approximately 2%. Embryologically, the normal anastomosis of the left and right sub-cardinal veins results in the left RV traveling on the ventral surface of the AA. However, in the case presented here, the left RV traveled on the dorsal side of the AA due to the anastomosis of the left and right supra-cardinal veins and regression of the anastomosis between the left and right sub-cardinal veins. If both the dorsal and ventral anastomoses remain, the left RV travels on the dorsal and ventral sides of the aorta. Some of the clinical problems reported in association with RLRV are hematuria and abdominal pain, and the risk of damaging the RLRV during surgery of the posterior abdominal wall. Venous variants as reported herein should be kept in mind when interpreting imaging of the posterior abdominal wall or performing surgery or other invasive procedures near the RLRV.

Cone-beam computed tomography gives us much useful morphological information about the mandibular bone. Many studies of the mandible include findings from this technique. However, there have been no endoscopic studies of the mandible. Sixteen sides of eight dry mandibles resected from cadavers (age range 38-83 years) were examined by endoscopy. The head of the endoscope was 2.0 mm in diameter. We examined the mandibular foramen, lingula, mylohyoid groove, and mandibular canal. The mylohyoid grooves showed variations such as double grooves and canals. The mandibular lingula was located superior or medial to the the mandibular foramen. In a single case, the medial wall inside the mandibular canal showed a porous surface. The retromolar canal was observed in three sides. None of the images in the present study have been seen in other studies. Observation of the retromolar canal from the mandibular canal in particular can help dental students as well as oral and maxillofacial surgeons to understand its morphology. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1875-1880, 2017. © 2017 Wiley Periodicals, Inc.

Recent studies using cone-beam computer tomography (CBCT) have added to our understanding of anatomical variation in the mandible of humans. However, the distribution of nerves cannot be revealed by CBCT. There have been investigations of the distribution of nerves relating to the mandible, but some proposed causes of these variations remain controversial. In this study, we observed a total of 10 sides from five mandibles of Macaca fascicularis of unknown age and sex using CBCT and dissection under stereomicroscopy. Nine of the 10 sides had two mental foramina in each side. Innervation by the mental nerves depended on the locations of those foramina. The long branch to the mandibular angle ran with a branch of the facial artery, which joined the mental artery in all 10 sides. Five specimens had a median perforating canal in the mandibular bone. In addition, a branch of the sublingual artery, which joined with the small branches of the submental artery, entered the mandibular bone from the median lingual foramen. This foramen was located in the lower part of the mandibular symphysis and passed via the median perforating canal to exit from the median labial foramen, also located in the lower part of the mandibular symphysis. We speculate that the median perforating canal of the mandible, rarely found in humans, is the remnant of the feeding artery of the fetal mandible, and in M. fascicularis is seen in all specimens because they have no mental protuberance. Anat Rec, 300:1464-1471, 2017. © 2017 Wiley Periodicals, Inc.

The zygomaticofacial branch (ZFb) of the zygomatic nerve passes through the lateral wall of the orbit anterolaterally and traverses the zygomaticofacial foramen (ZFFOUT). However, in terms of intraorbital course, only a few studies have focused on the orbital opening of the ZFb (ZFFIN) and related canal. Therefore, this study aimed to locate the orbital opening and exit of the ZFb of the zygomatic nerve. Twenty sides from 10 fresh frozen cadaveric Caucasian heads were used in this study. The vertical distance between inferior margin of the orbit and ZFFIN (V-ZFFIN), the horizontal distance between the lateral margin of the orbit and ZFFIN (H-ZFFIN), diameter of the ZFFIN (D-ZFFIN), the vertical distance between the inferior margin of the orbit and ZFFOUT (V-ZFFOUT), the horizontal distance between the lateral margin of the orbit and ZFFOUT (H-ZFFOUT), and the diameter of the ZFFOUT (D-ZFFOUT) were measured, respectively. The ZFFIN were located 5.1 ± 2.0 mm superior to the inferior margin of the orbit and 4.3 ± 1.6 mm medial to the lateral margin of the orbit. The ZFFOUT was located 1.2 ± 2.9 mm inferior to the inferior margin of the orbit and 1.1 ± 3.0 mm lateral to the lateral margin of the orbit. The diameter of the ZFFOUT was significantly larger than that of the ZFFIN. Additional knowledge of the zygomatic nerve and its branches might decrease patient morbidity following invasive procedures around the inferolateral orbit.

We report a case of bilateral lateral costal branches (LCB) of the internal thoracic artery (ITA). On the left side, the ITA branched from the subclavian artery as a common trunk with the thyrocervical trunk. The left LCB flew into the collateral branch of the fifth intercostal artery after reaching the upper end of the sixth rib and after exiting the left ITA at the upper part of the first rib. The left ITA was disconnected near the second rib because it had been used for coronary artery bypass surgery. The right ITA arose from the anterior surface of the right subclavian artery just after the right ITA diverged from the brachiocephalic artery. The right LCB reached the upper end of the fifth rib and flew into the collateral branch of the fourth intercostal artery. The right ITA descended along the back of the costal cartilages as usual. The mechanism of the development of the LCB is thought to be due to a lateral longitudinal anastomosis connecting the inter-node arteries arising from the dorsal aorta during the embryonic phase. More anatomical and embryological studies are necessary to further elucidate this variant arterial branch.

For various clinical/surgical procedures, it is important to accurately understand the location of the sinuatrial node (SAN). Therefore, this study's goal was to develop a new and simple method to visualize the SAN in human hearts. A total of 16 formalin-fixed human hearts were used in the study. After the epicardium was removed, the fat tissue on the myocardium's surface was brushed and removed in a solution of 40°C water with a surfactant to show the SAN's location. Once the structure considered to be the SAN was observed, histological observation was conducted with Masson's trichrome staining to confirm its identity. The working myocardium, SAN branch of the coronary artery, and the structure believed to be the SAN were observed in all specimens. Histological analysis confirmed this structure to be the SAN. We believe that the method described herein might contribute to a better understanding of the SAN's morphologic features and serve as an improved teaching aide. Clin. Anat. 33:232-236, 2020. © 2019 Wiley Periodicals, Inc.

Many dental procedures are at risk of injuring the lingual nerve. We performed this study to better elucidate the microanatomy that exists between the ipsilateral lingual and hypoglossal nerves so that iatrogenic injury can be avoided. Adult human cadaveric tongues (ten sides) underwent Sihler’s staining to identify the microanatomy between the lingual and hypoglossal nerves. The lingual nerve entered the middle part of the anterior two-thirds of the tongue from its lateral side and divided into two to four thick branches. These branches were then disseminated to the anterior, middle, and posterior parts of the anterior two-thirds of the tongue via 7–14 thin nerve bundles as terminal branches. The hypoglossal nerve entered the tongue at the posterior border of its anterior two-thirds and traveled forward to the apex of the tongue on all sides. All specimens were found to have communicating branches between the lingual and hypoglossal nerves at its anterior, middle, and posterior thirds. Our results indicate that the ipsilateral lingual and hypoglossal nerves constantly have three connections on each side between them. This knowledge might aid the dentist in minimizing iatrogenic nerve injury.

The transversus nuchae muscle appears inconsistently in the occipital region. It has gained attention as one of the muscles composing the superficial musculoaponeurotic system (SMAS). The purpose of this study was to clarify its detailed anatomical features. We examined 124 sides of 62 cadavers. The transversus nuchae muscle was identified when present and examined after it had been completely exposed. We also examined its relationship to the occipital cutaneous nerves.The transversus nuchae muscle was detected in 40 sides (40/124, 32.2%) of 26 cadavers; it was present bilaterally in 14 and unilaterally in 12. It originated from the external occipital protuberance; 43% of the observed muscles inserted around the mastoid process, and 58% curved upward around the mastoid process and became the uppermost bundle of the platysma. In one case, an additional bundle originated from the lower posterior border of the sternocleidomastoid muscle and coursed obliquely upward along with platysma. Ninety percent of the muscles ran below the sling through which the greater occipital nerve passed; 65% of the lesser occipital nerves ran deep to the muscle, and 55% of the great auricular nerves ran superficial to it. Our observations clarify the unique anatomical features of the transversus nuchae muscle. We found that it occurs at a rate similar to that described in previous reports, but its arrangement is variable. Further investigations will be performed to clarify its innervation and other anatomical features. Clin. Anat. 30:32-38, 2017. © 2016 Wiley Periodicals, Inc.

The omohyoid muscle typically has an inferior belly originating from the superior border of the scapula, and then passes deep to the sternocleidomastoid muscle where its superior belly passes almost vertically upward next to the lateral border of sternohyoid to attach to the inferior border of the body of the hyoid bone lateral to the insertion of sternohyoid. Herein, we report an unusual variant of the omohyoid and sternohyoid muscles. As the omohyoid muscle is commonly used as a surgical landmark during neck dissections, knowledge of its variations such as the one described in the current report is important to surgeons.

Objective Since the extreme lateral lumbar interbody fusion procedure was first reported by Ozgur in 2006, a large number of clinical studies have been published. Anatomical studies which explore methods to avoid visceral structures, such as the kidney, with this approach have not been examined in detail. We dissected the retroperitoneal space to analyze how the extreme lateral transpsoas approach to the lumbar spine could damage the kidney and related structures. Methods Eight sides from four fresh Caucasian cadavers were used for this study. The latissimus dorsi muscle and the thoracolumbar fascia were dissected to open the retroperitoneum. The fat tissue was removed. Steel wires were then put into the intervertebral disc spaces. Finally, the closest distance between kidney and wires on each interdiscal space was measured. Results The closest distance from the wire in the interdiscal space on L1/2, L2/3 and L3/4 to the kidney ranged from 13.2 mm to 32.9 mm, 20.0 mm to 27.7 mm, and 20.5 mm to 46.6 mm, respectively. The distance from the kidney to the interdiscal space at L4/5 was too great to be considered applicable to this study. Conclusions The results of this study might help surgeons better recognize the proximity of the kidney and avoid injury to it during the extreme lateral transpsoas approach to the lumbar spine.

An elongated styloid process (ESP) is present in 4% of the general population. It is sometimes found incidentally by panoramic radiography or computed tomography in the clinical setting. Few detailed morphometric studies of this phenomenon have been performed, however, especially regarding its histologic aspects. During anatomic dissection of a 71-year-old man who had died from cardiac failure and whose body had been donated to our department for medical student training, an ESP was found while disconnecting the stylohyoid muscle from the hyoid bone. It measured 88 mm in length. After resection, the ESP was examined using computed tomography and was assessed histologically. The results showed that it consisted of bone and cartilage. It was composed mainly of three types of cartilage with a beaded appearance. Masson trichrome staining revealed scattered collagenous fibers around the cartilage. Although ESP is not uncommon in the clinical setting, this huge ESP found during a dissection course and its detailed histologic investigation were considered sufficiently valuable to be reported.

Recent studies investigating accessory mental foramina using developments in diagnostic imaging have primarily defined the morphology of the foramina; however, few studies have described the structures passing through them. Additional clinical knowledge of the foramina is therefore required for preoperative diagnosis prior to surgery, including implant, periodontal and periapical surgery. In this study, we investigated the accessory mental foramina and the associated nerves and arteries in donated cadaveric mandibles using anatomical and radiological observation methods. We examined 63 mandibles with overlying soft tissue by cone-beam computed tomography and noted the existence of the accessory mental foramina. Mandibles with accessory mental foramina were subsequently analyzed. Additionally, the neurovascular bundles passing through these foramina were dissected using anatomical methods.The incidence of accessory mental foramina was 14.3%. The larger foramina tended to be located anteriorly or superiorly and proximal to the mental foramen, while the smaller foramina tended to be located posterosuperiorly and distal to the mental foramen. The mental foramen ipsilateral to the accessory mental foramen was smaller than the one contralateral to it. The comparatively distant and large accessory mental foramen included an artery.This study elucidated the relationship between accessory mental foramina and the associated nerves and arteries. We believe that the results will contribute to the clinical dentistry field.

Since three-dimensional computed tomography was developed, many researchers have described accessory mental foramina. The anatomical and radiological findings have been discussed, but details of accessory mental nerves (AMNs) have only been researched in a small number of anatomical and clinical cases. For this article, we reviewed the literature relating to accessory mental foramina (AMFs) and nerves to clarify aspects important for clinical situations. The review showed that the distribution pattern of the AMN can differ according to the position of the accessory mental foramen, and the reported incidence of AMFs differs among observation methods. A review of clinical cases also revealed that injury to large AMF can result in paresthesia. This investigation did not reveal all aspects of AMNs and AMFs, but will be useful for diagnosis and treatment by many dentists and oral and maxillofacial surgeons. Clin. Anat. 28:848–856, 2015. © 2015 Wiley Periodicals, Inc.

The detailed nervous system in the mandibular bone cannot be observed on computed tomography. Dental professionals need to understand the running route of the inferior alveolar nerve and can do so by using gross anatomical dissection. However, the nervous system is difficult to dissect and visualize clearly because it is surrounded by a hard cortical plate. To develop an educational material for dental professionals, we visualized the inferior alveolar nerve by using the decalcification technique. We believe that the use of this device can lead dentists to better understand the nervous anatomy of the mandibular bone.

Horseshoe kidney is a known congenital renal anomaly. During a gross anatomy dissection course for students in 2014, a horseshoe kidney was found in an 80-year-old female. The isthmus was formed by the fusion of the right and left kidneys at their lower poles and resulted in a U-shaped kidney. Both sides of the renal hilum opened ventrally. Four surplus renal arteries entered the horseshoe kidney. The first surplus renal artery arose from the right side of the abdominal aorta, and entered the lower part of the renal hilum. The second surplus artery arose from the ventral side of the abdominal aorta, and entered the left inferior part of the left renal hilum.The third surplus artery also arose from the ventral side of the abdominal aorta and entered the inferior border of the left part of the isthmus. The fourth surplus artery arose from the bifurcation of the common iliac arteries and distributed to the inferior border of the middle of the isthmus. One surplus renal vein arose from the lower border of the middle of the isthmus, descended dorsally to the abdominal aorta and the right common iliac artery, and then entered the upper wall of the left common iliac vein. The isthmus was made up of renal parenchymal structures. These findings will be useful as regards research and surgery on the horseshoe kidney. This was the eighth case of horseshoe kidney in our laboratory.

Vascular injection into extracted tissue may be associated with leakage due to excessive local injection pressure. Historically, this complication has been impossible to resolve because the injection pressure has been the only available force with which to send the agent to the peripheral vasculature. We have developed a new vascular injection method that utilizes a material affected by magnetic force and is therefore not solely dependent upon the injection pressure. We mixed the same weights of latex and magnetic fluid and injected the solution into the arterial stump of an extracted tissue specimen. Next, we used a permanent magnet to attract the agent into the peripheral vasculature. We repeated the injection and magnetic application until no further fluid could be injected. We used this method in 20 formalin-fixed tissue specimens. The vessels were clearly observable through to the peripheral areas, and leakage from the injected artery was minimal. This new agent has several beneficial characteristics: it is X-ray impermeable, is durable in the face of chemical insult, and allows for easy visual observation. The injected tissue can be studied for X-ray film examination, tissue clarification, and gross anatomical dissection. Additionally, this method can be applied to both fresh and formalin-fixed tissue. We consider that this method has the potential to expand the applications of injection studies.

The retromolar foramen (RMF) is the bony entrance of the retromolar canal, through which a neurovascular bundle runs. It is essential to locate such anatomic variants in a patient in order to avoid complications in surgery, implant placement, or anesthesia of the area. To our knowledge, there has only been one case report of supernumerary RMF, which reported one bilateral doubled retromolar foramina and one doubled left RMF. We present an extremely rare case in which a right triple RMF was observed on cone beam computed tomography in a cadaver. Diameters of the RMF were 0.8 mm, 1.0 mm and 1.1 mm, respectively. Distances from the distal edge of the third molar were measured as 4.0 mm, 3.6 mm, and 0.5 mm, respectively. RMF was not found on the left side of the mandible.

L-shaped kidney is a congenital anomaly. The disorder results in the kidney appearing very similar in shape to horseshoe kidney (also a congenital anomaly), but either the right or left kidney is located at a position lower than the other kidney. In this report, we describe a woman with L-shaped kidney, identified during anatomical dissection, and compare the findings with clinical data obtained before her death. We discuss the embryology of L-shaped kidney based on detailed anatomical data on the kidney and its vascular system obtained by means of gross anatomical, radiological, and histological examinations. Our findings indicate the importance of detailed anatomical information when planning surgical procedures in patients with fused kidneys, as well as kidney transplantation, resection of renal carcinoma, or surgical treatment of abdominal aortic aneurysm.

Introduction The accessory foramina could not be identified on some imaging modalities such as surface-rendered images. The purpose of this study was to investigate the ability of surface-rendered images in detecting these foramina. Materials and methods We analyzed 20 accessory mental foramina (AMF) in nine mandibles removed from cadavers with cone-beam computed tomography (CBCT) and assessed in surface-rendered images. All AMF were divided into three groups depending on their visibility. Results Group 1 included AMF that were clearly visible as foramina, Group 2 were not clearly visible but could be recognized with concave parts, and Group 3 were not visible and the smooth surface of the bone was observed. Group 1 ranged from 1.3 to 5.1 mm2, Group 2 from 0.3 to 3.8 mm2, and Group 3 from 0.2 to 1.1 mm2. A statistically significant difference in the mean size between Groups 1 and 3 was observed. Even if the AMF are smaller (e.g., 1 mm in diameter), they should still be avoided to prevent injury. Conclusions The clinician should be aware that smaller foramina might not be detected on these images.

Facial reanimation surgery using a free muscle flap for facial paralysis, in which gracilis muscle flap was used, was first reported by Harii1 in 1976. Subsequently, many muscle flaps for the surgery have been reported, such as latissimus dorsi (LD) muscle,2–4 rectus abdominis muscle,5 rectus femoris muscle,6 abductor hallucis muscle,7 internal oblique muscle,8 biceps femoris muscle,9 and pectoral minor muscle.10 Currently, in Asian countries, the LD muscle flap is the most commonly used among these muscle flaps because it has a long vascular pedicle and nerve. However, the LD muscle flap has 1 problem, that is, its thickness. In surgery, if the LD muscle flap is to be transplanted without thinning in the subcutaneous pocket of the cheek, (1) insertion of the muscle flap inside the pocket may be difficult due to its thickness, (2) convex deformation occurs due to its thickness, and (3) contraction of the muscle flap is too strong, and problems such as facial expression becoming asymmetrical in shape when the patient smiles occur. Therefore, in many cases, a method to shave the LD muscle flap before transplanting is followed, leading to substantially satisfactory results being stably obtained.2,3 However, there are no reports clearly indicating to what degree the muscle flap may be safely shaven. The purpose of this study is to anatomically investigate the three-dimensional route of the thoracodorsal artery, vein, and nerve inside the LD muscle used for facial reanimation and to clarify the degree to which the muscle flap may be safely shaven.

Cevimeline is a muscarinic agonist that promotes saliva secretion and is used to treat Sjögren's syndrome (SS), an autoimmune disorder in which the exocrine glands that produce saliva are destroyed. Cevimeline is thought to affect the composition of saliva in part by regulating the localization of aquaporins (AQPs). In this study, we investigated the effects of chronic Cevimeline administration in the salivary glands of SS mice on the immunohistochemical localization of aquaporin (AQP)-1, 3, 4, 5 and 8. We used Cevimeline-untreated SS mice, treated SS mice, discontinued SS mice and untreated normal mice. AQP-5 was found in the apical and lateral membranes of acinar cells in the parotid and submandibular glands of cevimeline-treated SS mice and untreated normal mice. Saliva secretion and AQP-5 localization were sustained in SS mice who were chronically administered Cevimeline and at four weeks after discontinuation. Unlike AQP-5, the localization of AQP-1, 3, 4 and 8 were not affected by Cevimeline administration. Our findings demonstrated that administration of Cevimeline maintains the proper localization of AQP-5 in the acinar cells of the salivary gland, which may promote salivation in chronically treated SS mice. Clinically, this suggests that chronic Cevimeline administration may be useful therapeutically for SS patients suffering from a decrease in saliva secretion by improving the disordered AQP-5 localization.

Cone-beam computed tomography gives us much useful morphological information about the mandibular bone. Many studies of the mandible include findings from this technique. However, there have been no endoscopic studies of the mandible. Sixteen sides of eight dry mandibles resected from cadavers (age range 38-83 years) were examined by endoscopy. The head of the endoscope was 2.0 mm in diameter. We examined the mandibular foramen, lingula, mylohyoid groove, and mandibular canal. The mylohyoid grooves showed variations such as double grooves and canals. The mandibular lingula was located superior or medial to the the mandibular foramen. In a single case, the medial wall inside the mandibular canal showed a porous surface. The retromolar canal was observed in three sides. None of the images in the present study have been seen in other studies. Observation of the retromolar canal from the mandibular canal in particular can help dental students as well as oral and maxillofacial surgeons to understand its morphology. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1875-1880, 2017. © 2017 Wiley Periodicals, Inc.

Purpose: In Japan, medical students are exposed to formaldehyde (FA) during gross anatomy dissection course. We have taken ongoing measures to decrease FA exposure at our university. This study eva...

Recent studies using cone-beam computer tomography (CBCT) have added to our understanding of anatomical variation in the mandible of humans. However, the distribution of nerves cannot be revealed by CBCT. There have been investigations of the distribution of nerves relating to the mandible, but some proposed causes of these variations remain controversial. In this study, we observed a total of 10 sides from five mandibles of Macaca fascicularis of unknown age and sex using CBCT and dissection under stereomicroscopy. Nine of the 10 sides had two mental foramina in each side. Innervation by the mental nerves depended on the locations of those foramina. The long branch to the mandibular angle ran with a branch of the facial artery, which joined the mental artery in all 10 sides. Five specimens had a median perforating canal in the mandibular bone. In addition, a branch of the sublingual artery, which joined with the small branches of the submental artery, entered the mandibular bone from the median lingual foramen. This foramen was located in the lower part of the mandibular symphysis and passed via the median perforating canal to exit from the median labial foramen, also located in the lower part of the mandibular symphysis. We speculate that the median perforating canal of the mandible, rarely found in humans, is the remnant of the feeding artery of the fetal mandible, and in M. fascicularis is seen in all specimens because they have no mental protuberance. Anat Rec, 300:1464-1471, 2017. © 2017 Wiley Periodicals, Inc.

To chew, it is necessary to maintain harmony between the masseter muscle and other organs. Various studies have been conducted on the masseter muscle, but none has examined the relationships among masseter muscle form, occlusal support of remaining teeth, and maxillofacial morphology. Thus, we conducted the present study using cadavers donated to anatomy practice. After the masseter muscle was extracted, its length, width, thickness, and volume were measured; histological observations were conducted; and the muscle fiber cross-sectional area and muscle density were calculated. In addition, denture use and non-use were examined. The results showed that when regional support loss occurs, muscle fiber thickness and density decrease. This in turn causes masseter muscle thickness and volume to decrease, resulting in muscle atrophy. Furthermore, excluding Eichner class A cases (all regions intact), the thickness of the masseter muscle is greatest when the premolar support region remains. The premolar support region was shown to have the most impact on masseter muscle morphology. These results suggest that atrophy of the masseter muscle can be arrested or improved with the use of dentures in the case of tooth loss.

Summary Background The objective of the current study is to elucidate the three-dimensional vascular distribution as far as the peripheral areas of a latissimus dorsi musculocutaneous flap and to establish a safe procedure for creating it. Methods A lead oxide with gelatin-contrast agent was injected into fresh cadavers and the angiosomes in the muscle and skin were examined in detail. Results In the muscle, three vascular territories were observed. The first vascular territory was formed by the thoracodorsal artery, the perforating branches of the ninth intercostal artery and those of the tenth intercostal artery located in the lateral part of the muscle. The second vascular territory was formed by the perforating branches of the tenth intercostal artery located in the medial part of the muscle, those of the 11th intercostal artery and the subcostal artery. The third vascular territory was formed by perforating branches of the first and second lumbar arteries. In the dorsal skin above the muscle, two vascular territories were observed. The first vascular territory was formed by perforating cutaneous branches of the thoracodorsal artery, perforating branches of the ninth through 11th intercostal arteries and the scapular circumflex artery. The second vascular territory was formed by perforating branches of the subcostal artery and the first and second lumbar arteries. Conclusions When using a latissimus dorsi musculocutaneous flap with the thoracodorsal artery as a pedicle, the flap can be safely elevated as far as the inferior border of the 12th rib where perforating branches of the subcostal artery are distributed. At the same time, skin above the muscle can be safely harvested up to the iliac crest. It is essential, however, that the skin paddle includes perforating branches of the ninth intercostal artery or perforating branches of the 10th intercostal artery in the lateral part of the muscle.

During a gross anatomy course at Kurume University School of Medicine in 2001, an anomaly of the kidneys was found. The lower ends of the kidneys were fused by a renal substance and formed a horseshoe kidney located ventral to the abdominal aorta and inferior vena cava. Both renal hila opened very widely in the ventral direction, with the left hilum being larger than the right. This horseshoe kidney had original left and right renal arteries that branched from the abdominal aorta. As well, there were four surplus renal arteries. The first surplus artery branched from the right renal artery and was distributed to the upper pole of the right kidney. The second arose from the abdominal aorta and was distributed to the inferior pole of the right kidney. The third arose from the abdominal aorta and was distributed to the inferior pole of the left kidney and part of the isthmus. The fourth branched from the abdominal aorta and was distributed to the upper pole of the left kidney. The incidence of horseshoe kidneys in Japanese anatomical dissections has been reported as 0.15-0.48%. This was the sixth such case for our laboratory, representing a frequency of 0.1% (6 of 1902 dissections) from 1952 to 2001.

We used an embryological approach to investigate development and microvasculature of lingual papillae, and expression of vascular endothelial growth factor (VEGF) in the rat tongue. Temporal changes in the rat tongue at each developmental stage from embryonic day 13 (E13) to postnatal day 7 (P7) were observed by intravascular injection of India ink and immunohistochemistry using a VEGF antibody. At E13, the primordium of circumvallate papilla was observed among various lingual papillae. VEGF was widely expressed at E16 on the proliferated epithelium and the connective tissue core of circumvallate papilla. Invasion by capillary sprouts forming the lingual papillae was observed at E17. The primordium of fungiform papillae was observed at E14. VEGF was strongly expressed around the basal cells of proliferated epithelial tissues of fungiform papillae at E17. At E18, blind-ended capillary sprouts invaded into connective tissue cores from subepithelial sinusoidal capillaries by sprout angiogenesis. At P1, the invading capillary sprouts formed loops by vascular remodeling. The primordium of foliate papillae was observed at E16. VEGF was slightly expressed, but uniformly at E17 on the epithelium, muscle cells, and fibroblasts of foliate papillae. At E18, vascular density was increased by angiogenesis. The primordium of filiform papillae was observed at E17. It was the last to develop among the lingual papillae. VEGF was expressed in the cytoplasm of grown epithelial cells of filiform papillae at E19, and in blind-ended capillary sprouts formed by angiogenesis in the connective tissue cores at E20. The capillary sprouts formed loops by vascular remodeling at P1. Consequently, VEGF was expressed on the papillary epithelium and connective tissue cores of papillae during development of the papillary epithelium, and invasion by capillary sprouts into each papillae was observed thereafter. These results suggest a close relationship between expression of VEGF and angiogenesis of lingual papillae in the rat.

Recent studies investigating accessory mental foramina using developments in diagnostic imaging have primarily defined the morphology of the foramina; however, few studies have described the structures passing through them. Additional clinical knowledge of the foramina is therefore required for preoperative diagnosis prior to surgery, including implant, periodontal and periapical surgery. In this study, we investigated the accessory mental foramina and the associated nerves and arteries in donated cadaveric mandibles using anatomical and radiological observation methods. We examined 63 mandibles with overlying soft tissue by cone-beam computed tomography and noted the existence of the accessory mental foramina. Mandibles with accessory mental foramina were subsequently analyzed. Additionally, the neurovascular bundles passing through these foramina were dissected using anatomical methods.The incidence of accessory mental foramina was 14.3%. The larger foramina tended to be located anteriorly or superiorly and proximal to the mental foramen, while the smaller foramina tended to be located posterosuperiorly and distal to the mental foramen. The mental foramen ipsilateral to the accessory mental foramen was smaller than the one contralateral to it. The comparatively distant and large accessory mental foramen included an artery.This study elucidated the relationship between accessory mental foramina and the associated nerves and arteries. We believe that the results will contribute to the clinical dentistry field.

This study aimed to evaluate students’ subjective symptoms associated with exposure to low levels of formaldehyde (FA) during a gross anatomy course and to survey how the risk of subjective symptoms was affected by exposure to FA. We conducted three questionnaire surveys of 125 students enrolled in an anatomy course (FA exposure group) and 124 students not enrolled in the course (FA nonexposure group) before, during, and 6 months after the course. The questionnaire included questions inquiring about subjective symptoms, sex, age, and allergies. We analyzed differences in the prevalence of subjective symptoms in distinct survey periods. Furthermore, we analyzed the relationship between the subjective symptoms and exposure to FA after adjusting for allergy, sex, and age using multiple logistic regression analysis. The prevalence of some of the ocular, nasal, and nonspecific symptoms in the FA exposure group was low before the course, increased during the course and decreased 6 months after the course. A significant positive relationship was observed between exposure to FA and some symptoms after adjusting for allergy, sex, and age. We identified some concrete symptoms associated with exposure to FA. We suggest that the exposure to low levels of FA influences students’ subjective symptoms.

Since three-dimensional computed tomography was developed, many researchers have described accessory mental foramina. The anatomical and radiological findings have been discussed, but details of accessory mental nerves (AMNs) have only been researched in a small number of anatomical and clinical cases. For this article, we reviewed the literature relating to accessory mental foramina (AMFs) and nerves to clarify aspects important for clinical situations. The review showed that the distribution pattern of the AMN can differ according to the position of the accessory mental foramen, and the reported incidence of AMFs differs among observation methods. A review of clinical cases also revealed that injury to large AMF can result in paresthesia. This investigation did not reveal all aspects of AMNs and AMFs, but will be useful for diagnosis and treatment by many dentists and oral and maxillofacial surgeons.

A case of dual origin of the left vertebral artery was encountered in a dissection course for medical students in 2014. Two vertebral arteries were observed on the left side. One arose from the aortic arch between the origin of the left common carotid artery and the left subclavian artery, entered the transverse foramen of the 4th cervical vertebra, and coursed upward into the transverse foramen. The other arose from the left subclavian artery as expected, divided into two branches anterior to the cervical vertebrae, and entered the transverse foramina of the 6th and 7th cervical vertebrae. Both branches flowed into the anterior spinal artery. Moreover, as seen in other anomalies, 3 arterial fenestrations were observed in the cranial arteries. This case is extremely unique with respect to the following points: the 2 ipsilateral vertebral arteries did not combine to form 1 vertebral artery, the vertebral artery of subclavian artery origin entered the transverse foramen of the 7th cervical vertebra, and 3 fenestrations were observed in the intracranial arteries. This is a very suggestive case for neurosurgeons and radiologists who perform treatments involving the vertebral artery.

This report describes a rare case of an arterial anomaly in the celiaco-mesenteric region, encountered in a Japanese female cadaver for dissection at the gross anatomy laboratory of Kurume University School of Medicine in 2003. The usual celiac trunk was not identified, and the left gastric artery, the splenic artery and the hepato-mesenteric trunk independently arose from the abdominal aorta. Moreover, the hepatic artery arising from the hepato-mesenteric trunk ran behind the portal vein. The classification for this type of arterial anomaly is a Type III' of Morita's classification and Type II of Higashi and Hirai's classification, not belong to the Adachi's.

In the surgical setting, horseshoe kidneys (HKs) may be a cause for confusion because of their complicated morphology, especially in the vicinity of the vascular and urinary collecting systems around the isthmus of the HK. In the patients with HK, analysis of the anatomical structure of the isthmus is both useful and necessary. The aim of this study is to observe the vascular and collecting system of the HK using anatomical and contrast imaging technique, then make use of the knowledge for clinical anatomy. A HK voluntarily donated post-mortem to our department in 2013 by an 80-year-old woman was dissected. The gross anatomy of this HK was reported. In this study, we additionally analyzed this kidney using micro-computed tomography with both colored and colorless contrast media after the kidney was made transparent. Contrast imaging clearly revealed that each of the five renal arteries, including the three surplus renal arteries, entering the HK distributed blood to different regions. Neither side of the urinary collecting system crossed the midline of the isthmus. Two surplus renal veins emerged from the HK and two ureters descended dorsal to the isthmus. These observations show that gross anatomical observation and contrast imaging of the HK can provide very important surgical information. Our results can contribute to both better understanding of fundamental knowledge and progress in the surgery of HKs such as in the setting of biopsy and transplantation.

Medical students and lecturers in Japan are exposed to formaldehyde (FA) during gross anatomy dissection courses. In 2011, our university renovated for the installation of dissection tables equippe...

A total of 548 upper limbs (276 right and 272 left hands) from Japanese cadavers were dissected. The arrangements of extensor indicis proprius, extensor digitorum communis (EDC), and extensor digiti minimi tendons and the intertendinous connections were studied. The most common pattern of extensor tendons was as follows: the index finger had a single EDC tendon, the middle finger had a single EDC tendon, the ring finger had a single EDC tendon, and the small finger had a single EDC tendon or a single common EDC tendon distributed to the ring and small finger. A single extensor indicis proprius tendon ran along the ulnar side of the EDC, and the extensor digiti minimi tendon consisted of 2 slips. Intertendinous connections were classified into 3 types: type 1 with a filamentous band, type 2 with a fibrous band, and type 3 with a tendinous band subdivided to r-shaped and y-shaped. The most common patterns were type 1 in the second intermetacarpal space (IMCS), type 3r in the third IMCS, and type 3y in the fourth IMCS.

We investigated the morphological characteristics of cervical nerve roots in 38 cadavers. The cadavers consisted of 20 males and 18 females with a mean age of 75 years (range : 44 to 93 years). The morphological correlation between the ventral nerve root and dorsal nerve root was classified into three types.Type I in which one anterior root joins one dorsal root. Type II in which two anterior roots join one dorsal root. Type III in which two anterior roots become one again and joins one dorsal root. The results of macroscopic investigation from C3 to C8 nerve roots in 38 cadavers were as follows : TypeI was mainly found in 261 roots (82.9%), typeII in 37 roots (11.7%), and type III in 17 roots (5.4%). In the lower cervical spine such as C6 and C7, type II and III were more frequently found than those of the upper cervical level.

This report describes a rare case of absence of the celiac trunk, which was encountered in a Japanese female cadaver in the dissecting room at Kurume University School of Medicine in 1993. In this case, the left gastric, the splenic, the common hepatic and the superior mesenteric arteries arose independently in that order from the abdominal aorta. In addition, the left aberrant hepatic artery arose from the left gastric artery. This anomalous case belongs to type 5 (Typus primitivus) of Morita's classification (1935), and is the fifth case of this kind of vascular variation to be reported in Japan.

The fabella is a sesamoid bone located in the proximal tendon of the gastrocnemius muscle. In rare cases, its presence may lead to a variety of clinical problems, including fabella syndrome and common fibular (CF) nerve palsy. The purpose of this study was to analyze the morphology of the fabella and CF nerve and discuss the influence of any existing fabellae on the size of the CF nerve. The morphology of the fabella and CF nerve in the popliteal region of the lateral head of the gastrocnemius muscle was investigated in 102 knees of 51 Japanese cadavers. The maximum circumference of the thigh, knee, and calf and the frequency, position, and size of the fabella were measured. In addition, the CF nerve width and thickness were measured proximal to the fabellar region and again as the CF nerve passed posterior, lateral, or medial to the region. A fabella was observed in 70 knees (68.6%). The CF nerve adjacent to the fabella was significantly wider and thinner than in the region proximal to the fabella (P < 0.001). In cases in which a bony fabella was present, there was a significant relationship between the thickness of the CF nerve and the circumference of the thigh and knee. The following factors were observed to contribute to the presence of a fabella causing alterations in the size of the CF nerve: a bony fabella, a CF nerve path posterior or lateral to the fabella, and subjects with a thin physique and bony fabella.

Sjogren's syndrome (SS) is an autoimmune disorder whose main symptoms include xerostomia and dry eyes. It has been demonstrated that abnormal expression of aquaporin (AQP)-5 in the parotid and submandibular glands in SS model mice was corrected by cevimeline. In the present study, we orally administered cevimeline hydrochloride (cevimeline) to female MRL/l mice, which are widely used as a model for SS, to immunohistochemically investigate the localization of AQP-5 in the salivary glands. We also assessed the ultrastructure of acinar cells in the submandibular glands. AQP-5 was expressed in the apical and lateral cell membranes of acinar cells in the parotid and submandibular glands of normal mice, but not in the sublingual glands. In contrast, AQP-5 was expressed not only in the cell membranes in the apical domains but also in the cytoplasm in the SS model mice, indicating that the localization of AQP-5 was disordered in the SS model mice. After administration of cevimeline, AQP-5 was predominantly localized in the cellular apical domains of the acinar cells. Electron microscopy revealed that administration of cevimeline to the SS model mice and normal mice markedly reduced the number of secretory granules, increased the area of the rough endoplasmic reticulum, and expanded the intercellular gaps in the cells of the submandibular acini. Condensed vacuoles were also observed in the Golgi apparatuses, indicating that secondary enhancement of secretion and production of saliva had occurred. Consequently, the results of the present study demonstrate that the administration of cevimeline to the SS model mice increased salivary secretion in the submandibular glands. Furthermore, cevimeline transiently normalized the localization of AQP-5 expression in the parotid and submandibular glands.