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The myodural bridge (MDB) complex are fibrous bridges that functionally connect the spinal dura mater to the suboccipital musculature. Previously, we described the maturational sequence of the MDB within the posterior atlanto-occipital interspace of the rat. The present paper describes the morphology and developmental maturation of the MDB within the posterior atlanto-axial interspace of the rat. In the present study, E18 embryonic rats, newborn rats, and adult rats were selected to evaluate the development and growth of the MDB. Within the posterior atlanto-axial interspace of the rat, the fibers of the MDB and its associated muscles, in the embryonic rat, were observed to be scarce and lightly stained. In contrast, these same structures observed in the postnatal rat were quite apparent and robustly stained. After birth, it was observed that MDB originated from the rectus capitis dorsal major muscle, extended forward and downward, and finally merged with the posterior atlanto-axial membrane. As the rats developed and matured, the observed MDB fibers passing through the posterior atlanto-axial interspace appeared denser and more organized. This study evidenced that the MDB fibers within the posterior atlanto-axial interspace were primarily composed of type I collagen fibers in the postnatal rat. By observing the suboccipital region, we are able to hypothesize that the MDB complex plays a key role in maintaining the subdural space located within the upper cervical segment during growth and development. This study provides a morphological basis for future research on the function of the MDB complex.

In 2016, two adult male sperm whales beached off of Yangkou Port in Nantong City, Jiangsu Province, China. The local government planned to preserve them as specimens, one was entrusted to Dalian Hoffen Biological Co., Ltd., and thus became the first sperm whale to be preserved by plastination. The other sperm whale was preserved in Nantong by the traditional stripping method (The skin was preserved, and then the prosthesis was filled into the skin to preserve the specimens. The material of the prosthesis was polyurethane. The outline of the animal was sculpted by suturing the skin like a bag and filling it with polyurethane). Plastination of such a large marine mammal allowed us to view the mutual adaptations of its internal structure to its specific living environment and daily habits. This sperm whale is the largest specimen in the world and this is the first time a sperm whale has been preserved using the plastination method. The plastination process also provides a method for studying the anatomy of large marine mammals for humans to understand deep-sea organisms at close contact and visual level. The plastination of this sperm whale promises to be a world class resource holding tremendous scientific, educational, and artistic value.

The cisterna magna has been defined as the space between the inferior margin of the cerebellar vermis to the level of the foramen magnum, while an enlarged dorsal subarachnoid space at the occipito-cervical junction extending from the foramen magnum to the upper border of the axis (C2) is still ignored. Recently, the myodural bridge complex is proved to drive the cerebral spinal fluid flowing via this region, we therefore introduce the “occipito-atlantal cistern (OAC)” to better describe the subarachnoid space and provide a detailed rationale. The present study utilized several methods, including MRI, gross anatomical dissection, P45 sheet plastination, and three-dimensional visualization. OAC was observed to be an enlarge subarachnoid space, extending from the foramen magnum to the level of the C2. In the median sagittal plane, OAC was a funnel shape and its anteroposterior dimensions were 15.92 ± 4.20 mm at the level of the C0, 4.49 ± 1.25 mm at the level of the posterior arch of the C1, and 2.88 ± 0.77mm at the level of the arch of the C2, respectively. In the median sagittal plane, the spino-dural angle of the OAC was calculated to be 35.10 ± 6.91 degrees, and the area of OAC was calculated to be 232.28 ± 71.02 mm2. The present study provides OAC is a subarachnoid space independent from the cisterna magna. Because of its distinctive anatomy, as well as theoretical and clinical significance, OAC deserves its own name.

The myodural bridge (MDB) is a dense connective tissue bridge connecting the suboccipital muscles to the spinal dura mater, and it has been proven to be a normal common existing structure in humans and mammals. Some scholars believe that the suboccipital muscles can serve as a dynamic cerebrospinal fluid (CSF) pump via the MDB, and they found head rotations promote the CSF flow in human body, which provided evidence for this hypothesis. Head movement is a complex motion, but the effects of other forms of head movement on CSF circulation are less known. The present study explored the effects of head-nodding on CSF circulation. The CSF flow of 60 healthy volunteers was analyzed via cine phase-contrast magnetic resonance imaging at the level of the occipitocervical junction before and after one-minute-head-nodding period. Furthermore, the CSF pressures of 100 volunteers were measured via lumbar puncture before and after 5 times head-nodding during their anesthetizing for surgical preparation. As a result, it was found that the maximum and average CSF flow rates at the level of the upper border of atlas during ventricular diastole were significantly decreased from 1.965 ± 0.531 to 1.839 ± 0.460 ml/s and from 0.702 ± 0.253 to 0.606 ± 0.228 ml/s respectively. In the meantime, the changes in the ratio of cranial and caudal orientation of the net flow volume were found differed significantly after the one-minute-head-nodding period (p = 0.017). And on the other hand, the CSF pressures at the L3–L4 level were markedly increased 116.03 ± 26.13 to 124.64 ± 26.18 mmH2O. In conclusion, the head-nodding has obvious effects on CSF circulation and head movement is one of the important drivers of cerebrospinal fluid circulation. We propose that the suboccipital muscles, participating in various head movements, might pull the dura sac via the myodural bridge, and thus, head movement provides power for the CSF circulation.

The myodural bridge (MDB) is a dense connective tissue structure between the suboccipital musculature and the spinal dura mater (SDM). However, few reports on the development and maturation of the human MDB. 30 head and neck specimens from human fetuses (F) from 12–40 weeks (W) were made into histological sections. The F12W sections evidenced that the SDM dominated by fibroblasts, attached to the posterior atlantoaxial membrane (PAAM) which completely sealed the atlantoaxial space. In the F13W stage, myofibrils of the suboccipital muscle fibers increased significantly in number. At the F14W stage, a gap was observed at the caudal end of the PAAM. Numerous myodural bridge-like structures were observed blending into the SDM through the gap. At the F15W stage, the MDB fibers originated between the posterior arch of atlas (C1) and the obliquus capitis inferior muscle, and extended forward and downward into the spinal canal through the atlantoaxial gap. Starting at the F21W stage, the MDB fibers were observed to pass through the atlantoaxial interspace and radially attach to the SDM. The present study adds to the knowledge base of developmental morphology research of the human embryonic MDB and provides a developmental morphological basis for its potential functionality.

The myodural bridge complex (MDBC) is described as a functional anatomic structure that involves the dense connective tissue fibers, muscles, and ligaments in the suboccipital region. It has recently been proposed that the MDBC can influence cerebrospinal fluid (CSF) circulation. In the present study, bleomycin (BLM), a type of antibiotic that is poisonous to cells, was injected into the posterior atlanto-occipital interspace (PAOiS) of rats to induce fibrous hyperplasia of structures in PAOiS. Sagittal sections of tissues obtained from the posterior-occipital region of the rats were stained utilizing the Masson Trichrome staining method. Semiquantitative analysis evidenced that the collagen volume fraction of collagen fibers of the MDBC, as well as the sum of the area of the spinal dura mater and the posterior atlanto-occipital membrane in the BLM group were significantly increased (p .05) compared to that of the other groups. This finding illustrates that the MDBC fibers as well as other tissues in the PAOiS of rats in the BLM group developed fibrotic changes which reduced compliance of the spinal dura mater. Indeed, the sectional area of the rectus capitis dorsal minor muscle in the BLM group was measured to be increased. These changes may further restrict CSF flow. The present research provides support for the recent hypothesis proposed by Labuda et al. concerning the pathophysiology observed in symptomatic adult Chiari malformation Type I patients, that there exists a relationship between the altered compliance of the anatomic structures within the craniocervical region and the resultant compensatory hyperplasia of the MDBC.

Background To study the anatomical characteristics of retro-orbicularis oculi fat (ROOF) in the upper eyelid and to investigate its relevance in upper eyelid surgery. Methods Thirty-eight Chinese hemifacial cadaver specimens were used. Several sagittal plane section planes were recorded from the medial canthus to the lateral canthus of the eyelid after P45 sheet plastination. ROOF and the associated orbital septum connective tissues in the 38 hemifaces were studied. According to the anatomic results, the lowest point of the junction of the orbital septum and the ROOF (SRJ) was raised for surgical dissection. We improved the intraoperative management of patients who underwent upper eyelid surgery in the plastic surgery department of the First Affiliated Hospital of Dalian Medical University in 2019. Patients were evaluated by observation and self-assessment. Results ROOF is fascia adipose tissue. In the upper portion of upper eyelid, ROOF fibers were observed to be extremely dense and continuous with the fascia on the surfaces of orbicularis oculi muscle, the periosteum of the orbital margin, and the orbital septum. In the middle portion, positional relationships were identified between the lowest point of the SRJ and the lowest point of the junction of the orbital septum and the levator palpebrae superioris (SAJ). Lifting the SRJ significantly increased the upper eyelid reflex distance in all 57 patients. Conclusions ROOF is an important factor in upper eyelid surgery. Lifting the SRJ effectively improves the retraction force of the levator palpebrae superioris muscle (LPS).

Purpose Few reports have been published regarding the microanatomy of the dura mater located at the craniovertebral junction (CVJ). In clinic, the precise microanatomy of the CVJ dura mater would be taken into account, for reducing surgical complications and ineffective surgical outcomes. The main objective of the present investigation was to further elucidate the fiber composition and sources of the cervical spinal dura mater. Methods The formalin-fixed adult head and neck specimens (n = 21) were obtained and P45 plastinated section method was utilized for the present study. The fibers of the upper cervical spinal dura mater (SDM) were examined in the P45 sagittal sections in the CVJ area. All photographic documentation was performed via a Canon EOS 7D Mark camera. Results The posterior wall of the SDM sac at CVJ was found to be composed of stratified fibers, which are derived from three sources: the cerebral dura mater, the occipital periosteum, and the myodural bridge (MDB). The proper layer of the cerebral dura mater passes over the brim of the foramen magnum and enters the vertebral canal to form the inner layer of the SDM, and the fibers originating from the periosteum of the brim of the foramen magnum form the middle layer. The fibers of the MDB are inserted into the SDM and form its outer layer. It was found that the total number of fibers from each origin varied in humans. Conclusion At the CVJ, the posterior wall of the SDM is a multi-layered structure composed of three different originated fibers. The cerebral dura mater, the periosteum located at the brim of the foramen magnum, and MDB contribute to the formation of the SDM. The present study would be beneficial to the choice of surgical approach at the CVJ and the protection of the SDB.

The aim of this study was to elucidate the relationships between the nasolabial fold and superficial fascia on histology and P45 sheet plastination.Two centimeter width specimen of the nasolabial area were harvested from the skin to periosteum. Then, 10-μm sections were made, stained with Masson trichrome, and observed under a light microscope. Three head and neck specimens were sliced in horizontal sections (46 slices) using P45 sheet plastination (polyester resin corrosion-resistant method designed to preserve biological sectional specimens in situ). Through slicing, bleaching, dehydration, casting, forced impregnation, curing, cutting, and sanding the molds, P45 plastination provided good light transmission, allowing the internal structures within the sheet to be revealed clearly in their intact form.The observations on histology and P45 sheet plastination correlated well. The nasolabial fold consisted of the superficial fatty layer of superficial fascia (SFS). At the beginning of the alar groove level, the nasolabial groove was located on the point where the medial limit of SFS met the levator labii superioris. At the alar base level, the nasolabial groove was located where the medial limit of the SFS met levator labii superioris. At the mouth corner level, the nasolabial groove was located where the medial limit of the SFS met the modiolus, including the orbicularis oris. The superficial fascia became scanty near the nasolabial groove, and the SFS comprised the nasolabial fold.The results of the present study may be helpful for applying subcutaneous dissection or sub-superficial muscular aponeurotic system dissection in rejuvenation of the nasolabial area.

In this paper, the authors attempted to determine the extent of the superficial fascia of the cheek using P45 sheet plastination.Three head and neck specimens were sliced in horizontal (46 slices), coronal (30 slices), and sagittal (29 slices) sections using P45 sheet plastination (special polyester resin corrosion-resistant method designed to preserve biological sectional specimens in situ). Through slicing, bleaching, dehydration, casting, forced impregnation, curing, cutting, and sanding the molds, P45 plastination sheets provided good light transmission, allowing the internal structures within the sheet to reveal clearly in their intact form.P45 sheet plastination revealed that the superficial fascia in the cheek area is generally composed of 3 layers: a superficial fatty layer, a membranous layer, and a deep fatty layer. Anteriorly, the membranous layer of superficial fascia (MSF) extended to the posterior border of the zygomaticus major muscle, enveloping this muscle, and then to the lateral border of the orbicularis oculi muscle. Posteriorly, the MSF extended to the anterior border of the parotid gland, and then was continuous with the parotid fascia. Superiorly, the MSF extended to the line from the tragus to the alar base. Inferiorly, the MSF extended to the line from the mandibular angle to the mouth corner. Below this line, the SMAS continued to the upper border of the platysma muscle.Our results using P45 plastination concorded well with Mitz's original drawing. We suggest that the results of the present study may be helpful for practicing surgeons to apply in subcutaneous dissection or sub-SMAS dissection in facelift procedures.

To reveal differences in the pattern of trabecular architecture in the epiphysis and metaphysis of the proximal tibia. The trabecular architecture of the proximal tibia was observed in 27 P45 plastinated knee specimens. In the medial and lateral condyles, under the articular cartilage surrounded by the medial or lateral meniscus, the cancellous bone is formed by thick and dense trabecular bands, which run longitudinally in the epiphysis and then pass through the epiphyseal line to terminate on the slanted cortex of the metaphysis. In the intercondylar eminence, the trabeculae are arranged basically in a network. In the central portion of the tibial metaphysis, cancellous bone consists of fine arcuate trabeculae, which extend to the anterior and posterior cortices, respectively. These trabeculae are intersected sparsely and form trusses over the medullary cavity. Near the areas of attachment of the iliotibial tract, tibial collateral ligament, anterior and posterior cruciate ligaments, and patellar ligament, the cancellous bone is locally reinforced with patchy trabeculae, dense radiating trabeculae, or two orthotropic trabecular bands. This study provides further accurate anatomical information on the trabeculae of the proximal tibia. The soft structures of knee joint, including the articular cartilage, menisci, and ligaments, and the slanted cortices of the metaphysis are important landmarks for the location of different arrangements of the cancellous architecture. The present results are beneficial for clinical diagnosis and treatment of pathologies of the knee joint, or the establishment of a finite element analysis model of the knee joint.

Background The fibula is only indirectly involved in the composition of the human knee joint and has therefore been neglected in the research on knee osteoarthritis. Nonuniform settlement of the proximal tibia plateau is clinically defined as when the height of the medial tibial plateau is lower than that of the lateral side in medial compartment knee osteoarthritis (KOA). The non-uniform settlement of the proximal tibia plateau may be caused by fibular support on the lateral side. Orthopedic surgeons practice partial fibulectomy based on the clinical manifestation of nonuniform settlement, and this technique has been shown to reduce pain and improve function in patients with medial compartment KOA. However, this hypothesis of the mechanism of nonuniform settlement lacks an anatomical basis. Methods The P45 polyester plastination technique was used to prepare sections of the proximal tibiofibular joint to investigate the distribution of the bone trabeculae in the region of the lateral tibial plateau. Results There was uneven distribution of trabeculae in the lateral condyle of the tibia and the head and neck of the fibula. The fibula and the posterolateral cortex of the shaft of the tibia united to form an arch beam via the tibiofibular joint. Many thick, dense trabeculae were present in a longitudinal direction above the tibiofibular arch. Conclusions The fibula supports the lateral tibial plateau, and the trabeculae were concentrated above the tibiofibular arch.

Background:The popliteal muscle-tendon complex (PMTC) belongs to the deep structure of the posterolateral complex (PLC) of human knee, which plays an important role in the posterolateral stability of the knee joint. At present, the anatomical relationship between the popliteal muscle and its adjacent structures remains controversial, especially the posterior cruciate ligament (PCL) and popliteal muscle. The revealation of anatomical connection between the popliteus muscle and its deep structures could provide an anatomical basis for the reconstruction of the PLC injury.Methods: To observe and analyze the relationship between popliteal muscle and the PCL, posterior meniscofemoral ligament (PMFL), lateral meniscus and articular capsule (AC). The dissection of 7 cases of adult human knee joint fixed with formalin, and 9 cases of sagittal P45 plastinated section of the knee joint were involved in this study. Results: For the popliteal muscle, the anatomical dissection showed that at the posterior edge of the platform of the lateral condyle of the tibia, at the tendon-muscle transition, from medial to lateral, separately sent out: dense connective tissue to connect with the PCL, dense fiber bundles to connect with the PMFL, and dense connective tissue band to connect the lateral meniscus. Meanwhile, the results of the P45 section revealed that the popliteal muscle fascia ran superiorly over the posterior edge of the tibialintercondylar eminence, andturned forward to be integrated into the PCL. Laterally, near the posterior edge of the lateral tibial plateau, the popliteal tendon penetrates through the articular capsule, where two dense fiberous bundleswere given off upwards by the popliteal tendon: one was the ventral fiber bundle,which ran superiorly over the posterior edge of the tibial plateau and then moved forwards to connect with the lateral meniscus; the dorsal fibersbundle ascended directly and participated in the AC.Conclusion: Popliteus muscle was connected with PCL, AC, lateral meniscus, and PMFL via the dense connective tissues near its tendon-muscle transition.

A dense bridge-like tissue named the myodural bridge (MDB) connecting the suboccipital muscles and the spinal dura mater was originally discovered in humans. Recent studies have revealed that the MDB confirmed a universal existing normal anatomical structure in mammals which is considered being significant in physiological functions. Our previous investigations have confirmed the existence of MDB in the finless porpoises. We conduct this research to expound the specificity of the MDB in Neophocana asiaeorientalis (N.asiaeorientalis). Five carcasses of N.asiaeorientalis with formalin fixation were used for this study. Two were used for head and neck CT scanning, three-dimensional reconstruction, and dissection of suboccipital region. One was used for P45 plastinated sheets observation. One was for histological analysis of suboccipital region. One was for Scanning electron microscopic study. The results showed that the MDB in N.asiaeorientalis is an independent muscle originated from the caudal border of occiput, directly extended through the posterior atlanto-occipital interspace and connected with the cervical spinal dura mater. Thus the MDB in N.asiaeorientalis is an independent and specialized muscle. Based on the origin and termination of this muscle, we could name it as ‘Occipital-Dural Muscle’. And the direct pull on the cervical spinal dura mater might affect the circulation of the cerebrospinal fluid (CSF) by altering the volume of subarachnoid space of spine.

This study aimed to examine the accurate location and boundary of the parotid gland in Koreans.Forty hemifaces from embalmed cadavers (mean age: 73 years) were studied. The line connecting the porion, gonion, and gnathion was used as a reference line. To measure the boundary of the parotid gland, the Frankfort horizontal line was used as the x-axis, whereas the vertical line passing through the porion was used as the y-axis. All measurements were taken from the lateral side of the face.The parotid gland has a variety of shapes: irregular, reverse triangle, and falciform. In all specimens, the boundary of the parotid gland was located 20 to 60 mm below the Frankfort horizontal line and located 10 mm anterior to the y-axis. On average, the most anterior and posterior distances of the parotid gland from the porion-gonion line were 36.4 ± 13.9 mm and 20.1 ± 10.5 mm, respectively, and the most inferior distance of the parotid gland from the gonion-gnathion line was 9.8 ± 5.8 mm. All specimens of parotid glands were found within an area 20 to 40 mm below the Frankfort horizontal line and 10 mm to the left of the y-axis. The most anterior point of the parotid gland was observed at varying locations. The maximum value of the most anterior point was 61.26 mm; it rarely exceeded the ectocanthion. The most posterior points of the parotid gland were located between the mastoid process and sternocleidomastoid muscle.These results might be useful for preventing injury to the parotid gland during facial rejuvenation procedures.

Recent studies have evidenced that the anatomical structure now known as the myodural bridge (MDB) connects the suboccipital musculature to the cervical spinal dura mater (SDM). In humans, the MDB passes through both the posterior atlanto-occipital and the posterior atlanto-axial interspaces. The present authors suggest that the MDB has important physiological functions in humans. The existence of the MDB in various mammals, including flying birds (Rock pigeons and Gallus domesticus) has been previously validated. Gentoo penguins are marine birds, able to make 450 dives per day, reaching depths of up to 660 feet. Gentoo penguins are also the world’s fastest diving birds. The present study was therefore carried out to investigate the existence and characteristics of the MDB in Gentoo penguin (Pygoscelis papua), a non-flying, marine bird that can dive. While foraging, this penguin is able to reach speeds of up to 22 miles per hour. For this study, six Gentoo penguin specimens were dissected to observe the existence and composition of their MDB. Histological staining was also performed to analyze the anatomic relationships and characteristic of the MDB in the Gentoo penguin. In this study, it was found that the suboccipital musculature in the Gentoo penguin consists of the rectus capitis dorsalis minor (RCDmi) muscle and rectus capitis dorsalis major (RCDma) muscle. Dense connective tissue fibers were observed connecting these two suboccipital muscles to the spinal dura mater (SDM). This dense connective tissue bridge consists of primarily type I collagen fibers. Thus, this penguin’s MDB appears to be analogous to the MDB previously observed in humans. The present study evidences that the MDB not only exists in penguins but it also has unique features that distinguishes it from that of flying birds. Thus, this study advances the understanding of the morphological characteristics of the MDB in flightless, marine birds.

Study design A scanning electron microscopic study performed on three cadaveric specimens focused on the human suboccipital region, specifically, myodural bridge (MDB). Objective This study showed the connection form of the MDB among the suboccipital muscles, the posterior atlanto-occipital membrane (PAOM) and the spinal dura mater (SDM), and provided an ultrastructural morphological basis for the functional studies of the MDB. Summary of background data Since the myodural bridge was first discovered by Hack, researches on its morphology and functions had been progressing continuously. However, at present, research results about MDB were still limited to the gross anatomical and histological level. There was no research report showing the MDB's ultrastructural morphology and its ultrastructural connection forms between PAOM and SDM. Methods A scanning electron microscope (SEM) was used to observe the connection of myodural bridge fibers with PAOM and SDM in atlanto-occipital and atlanto-axial interspaces, and the connection forms were analyzed. Results Under the SEM, it was observed that there were clear direct connections between the suboccipital muscles and the PAOM and SDM in the atlanto-occipital and atlanto-axial spaces. These connections were myodural bridge. The fibers of the myodural bridge merged into the spinal dura mater and gradually became a superficial layer of the spinal dura mater. Conclusion MDB fibers merged into the SDM and became part of the SDM in the atlanto-occipital and atlanto-axial space. MDB could transfer tension and pulling force to the SDM effectively, during the contraction or relaxation of the suboccipital muscles. Level of evidence N/A.

Background To evaluate the maximal sectional area (SA) of the rectus capitis posterior minor (RCPmi) muscle and its potential correlation with to be named ligament (TBNL) in the suboccipital area using 3D MR imaging. Methods A total of 365 subjects underwent sagittal 3D T2WI MR imaging of the RCPmi and TBNL. Among them, 45 subjects were excluded due to a particular clinical history or poor image quality. Finally, 320 subjects met the inclusion criteria, including 138 men and 182 women. The 624 RCPmi muscles were classified into positive and negative groups according to their attachment to the TBNL. Two experienced radiologists manually measured the maximum SA of the RCPmi muscle on the parasagittal image with a 30° deviation from the median sagittal plane. The correlations between the SA and the subject’s age, height, BMI, gender, handedness, and age-related disc degeneration were tested by Spearman analysis. The SA differences between different groups were compared using independent samples t-test. Results A total of 123 RCPmi-TBNL attachments were identified in the positive group, while 501 RCPmi muscles were identified in the negative group. The SA of the 624 RCPmi muscles was 62.71 ± 28.72 mm2 and was poorly correlated with the subject’s age, BMI, or handedness, with no correlation with age-related disc degeneration. A fair correlation was found between the SA and the body height in the whole group, and poor correlation in each male/female group. The SA of the RCPmi muscle in males was significantly bigger than that in women ([75.54 ± 29.17] vs. [52.74 ± 24.07] mm2). The SA of RCPmi muscle in the positive group was significantly smaller than that in the negative group ([55.95 ± 26.76] mm2 vs. [64.37 ± 28.97] mm2). Conclusions Our results revealed a significantly smaller SA of the RCPmi in subjects with RCPmi-TBNL attachment. Besides, a larger SA of the RCPmi was correlated with the male gender. These findings suggest that the SA of the RCPmi ought to be interpreted with care for each patient since there could be considerable variations.

SUMMARY: The myodural bridge (MDB) is confirmed that connecting the most of suboccipital muscles to the cervical dura mater through the posterior intervertebral spaces and widely exists in mammals and birds. In order to reveal whether the MDB is universally existing in amniota of vertebrates, we explored the existence and the morphological features of the MDB in the Trachemys scripta elegans. Twenty fresh red-eared slider specimens were observed by the gross anatomy dissection and histological analysis. In the results, three kind of muscles in the postoccipital region of the red-eared slider were found. The rectus capitis dorsum minor muscle originated from the posterior margin of the occiput (C0) and terminated at the spinous process of the atlas (C1). The transversospinales muscle was attached to the vertebral arch and the postzygapophysis of the atlas and extended to the spinous process of the axis (C2). The C2-C3 intertransversales muscle were extended from the postzygapophysis of C2 and the one of C3. The three muscles covered the dorsal interspaces among C0-C3, and meantime they were closely connected with dense connective tissues, which filled in these interspaces. Each of these thick dense connective tissue membranes sent off several short and strong fibrous bundles ventrally to merge with the cervical spinal dura mater. Furthermore the connective tissues connecting these muscles with cervical spinal dura mater directly were revealed under the microscopy and they consisted of parallel and intensive collagen fibers with orientation from dorsal to ventral. In conclusion, this study for the first time demonstrated the existence of the MDB in the testudines, in all of the dorsal atlantooccipital, atlantoaxial and C2-C3 intervertebral spaces. Based on our results and comparative anatomical evidences in recent year, it could be inferred that the MDB might be its highly conserved structure in the evolution of amniota.

Background: Understanding the aging process of the midface skeleton is considered crucial for correct facial rejuvenation. However, the canine fossa, an important morphological feature of the midface skeleton, has not yet been observed in connection with aging, despite the fact that it is the most main part of the maxillary bone. Here, the authors focus on the depression of the canine fossa to evaluate the Asian midface skeleton. Materials and methods: Computed tomography (CT) scans of the facial skeleton of 114 Koreans (59 males and 55 females) were reconstructed to three-dimensional (3D) images using a 3D analysis software programme. The study subjects included 27 young males, 32 old males, 28 young females and 27 old females. The angular measurements of three bony regions were measured for each 3D model: the canine fossa angle (assessing depth of the canine fossa), the maxillary angle (assessing orientation of the lateral maxilla) and the piriform angle (assessing orientation of the medial maxilla). Results: The canine fossa angle showed a statistically significant decrease with aging in both sexes, indicating the canine fossa actually becomes more concave with age. In contrast, the maxillary and piriform angle showed statistically insignificant changes with aging in female subjects. Conclusions: These results suggest that the canine fossa may be one of the effective markers to evaluate the anatomical changes to the facial skeleton with midface aging. (

The “myodural bridge” was described in literatures as a dense fibrous tissue connecting the sub-occipital musculature with the spinal dura mater in human studies. Now the concept of “myodural bridge” was perceived as an exact anatomical structure presumably essential for critical physiological functions in human body, and might exist in other mammals as well. To determine the existence of the “myodural bridge” in other mammals and to lay a foundation for the functional study, we examined representatives in five different mammalian orders. Based on the anatomical dissections, P45 plastinated sections and histological sections, we found that a dense fibrous tissue connected the rectus capitisdorsalis minor and the spinal dura mater through the dorsal atlanto-occipital interspace with or without the medium of the posterior atlanto-occipital membrane. These observed connective tissues were very similar to the “myodural bridge” previously described in humans. We proposed that the “myodural bridge”, as an evolutionally conserved structure, presents in many other mammals. Moreover, we believed that the “myodural bridge” might be a homologous organ in mammals. Thus, this study could provide an insight for our understanding the physiological significance of the “myodural bridge”, especially in human.

The location of perianal abscesses and the course of the fistula follow certain patterns, especially in the relationship between external and internal openings. However, it is still not clear how the contents of the ischioanal fossa, especially the fibrous network of fat tissue, affect the route for such diseases. Ten male adult cadavers were selected for the study. Seven horizontal transverse section planes from 1 cm above the pubic symphysis to the inferior border of the lesser trochanter of the femur were recorded after P45 sheet plastination. We observed characteristics of fiber distribution in the ischioanal fossa and its relationship with surrounding structures in every plane. There was a dense strip-type fiber connecting with junction fascia between the obturator internus and gluteus maximus muscles. Close to the levator ani, obturator internus, and gluteus maximus, the fibers were very dense and continuous with the fascia on the surfaces of these three muscles. The function of the fibrous network was considered to be not only the support of fat tissue in the fossa but also cushioning during physiological actions such as defecation. We hope that these morphological results could help to elucidate the passage of fistulae and the locations susceptible to perianal abscesses. Clin. Anat. 30:1029-1033, 2017. © 2017 Wiley Periodicals, Inc.