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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.

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.

During mammalian evolution, the Myodural Bridges (MDB) have been shown to be highly conserved anatomical structures. However, the putative physiological function of these structures remains unclear. The MDB functionally connects the suboccipital musculature to the cervical spinal dura mater, while passing through the posterior atlanto-occipital and atlanto-axial interspaces. MDB transmits the tensile forces generated by the suboccipital muscles to the cervical dura mater. Moreover, head movements have been shown to be an important contributor to human CSF circulation. In the present study, a 16-week administration of a Myostatin-specific inhibitor, ACE-031, was injected into the suboccipital musculature of rats to establish an experimental animal model of hyperplasia of the suboccipital musculature. Using an optic fiber pressure measurement instrument, the present authors observed a significant increase in intracranial pressure (ICP) while utilizing the hyperplasia model. In contrast, surgically severing the MDB connections resulted in a significant decrease in intracranial pressure. Thus, these results indicated that muscular activation of the MDB may affect CSF circulation, suggesting a potential functional role of the MDB, and providing a new research perspective on CSF dynamics.

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.

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.

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.

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.

In 1977, plastination was unveiled, which replaced tissue fluid with a curable polymer. Today preservation via plastination of various animal and plant tissues, organs, and whole bodies is an extremely useful technique to display such and help educate vast arrays of both allied science students and the lay public across the planet. The diversity of applications of plastination techniques seems to be without limits. In fact, the only real limitation to plastination is one's imagination! The size of plastinates during the early years of plastination was comparatively small and dictated primarily by the size of the available plastination kettle/chamber, 35 L Heidelberg plastination kettle (49 cm H × 34.5 cm diam.). In the 1990s larger chambers were designed and slowly became available:150-210 cm (long) × 65-80 cm (wide) and 83-92 cm (high). Today a few large vacuum chambers are in service which will accommodate whole bodies of man and domestic or exotic animals. Today, at least two gigantic chambers are available to impregnate massive specimens. These are 3.5 m × 2 m × 1.5 m (Dalian) and 4 m × 3 m × 2.2 m (Guben). Also, the need for larger quantities of acetone and impregnation mix, not to mention the great increase in specimen preparation time, makes this a major investment. The "cold temperature process" is used to impregnate these massive creations. The room temperature technique could be used. The same four plastination steps are necessary for larger and massive specimens. Besides their tremendous size, the slippery silicone polymer is a reckoning force.

The connective tissue between suboccipital muscles and the cervical spinal dura mater (SDM) is known as the myodural bridge (MDB). However, the adjacent relationship of the different connective tissue fibers that form the MDB remains unclear. This information will be highly useful in exploring the function of the MDB. The adjacent relationship of different connective tissue fibers of MDB was demonstrated based upon three-dimensional visualization model, P45 plastinated slices and histological sections of human MDB. We found that the MDB originating from the rectus capitis posterior minor muscle (RCPmi), rectus capitis posterior major muscle (RCPma) and obliquus capitis inferior muscle (OCI) in the suboccipital region coexists. Part of the MDB fibers originate from the ventral aspect of the RCPmi and, together with that from the cranial segment of the RCPma, pass through the posterior atlanto-occipital interspace (PAOiS) and enter into the posterior aspect of the upper cervical SDM. Also, part of the MDB fibers originate from the dorsal aspect of the RCPmi, the ventral aspect of the caudal segment of the RCPma, and the ventral aspect of the medial segment of the OCI, enter the central part of the posterior atlanto-axial interspace (PAAiS) and fuse with the vertebral dura ligament (VDL), which connects with the cervical SDM. Our findings prove that the MDB exists as a complex structure which we termed the ‘myodural bridge complex’ (MDBC). In the process of head movement, tensile forces could be transferred possibly and effectively by means of the MDBC. The concept of MDBC will be beneficial in the overall exploration of the function of the MDB.

The dense connective tissue that connects muscles to the cervical spinal dura mater is known as the myodural bridge in human anatomy and has been a subject of interest to anatomists and clinicians. The myodural bridge was originally discovered in humans, and also has been observed in other mammals and in reptilian sauropsids. We investigated the existence of the myodural bridge in a bird, that is, the Common Rock Pigeon Columba livia, to expand the understanding of the structure and function of the myodural bridge. Gross anatomical dissection of seven specimens and histological analyses of the suboccipital region of eight specimens were performed. The rectus capitis dorsalis minor muscle joins occipital periosteal extensions and inserts with several dense connective tissue cords on the dorsal side of the dura mater of the cervical spinal cord. The myodural bridge consists primarily of collagen Type I fibres, suggesting that the myodural bridge can transmit strong tensional forces generated by the contraction of M. rectus capitis dorsalis minor to the dura mater. The pull on the dura mater may affect the circulation of the cerebrospinal fluid in the subarachnoid space of the spine.

Background Context Studies over the past 20 years have revealed that there are fibrous connective tissues between the suboccipital muscles, nuchal ligament, and cervical spinal dura mater (SDM). This fibrous connection with the SDM is through the posterior atlanto-occipital or atlantoaxial interspaces and is called the myodural bridge (MDB). Researchers have inferred that the MDB might have important functions. It was speculated that the function of MDB might be related to proprioception transmission, keeping the subarachnoid space and the cerebellomedullary cistern unobstructed, and affecting the dynamic circulation of the cerebrospinal fluid. In addition, clinicians have found that the pathologic change of the MDB might cause cervicogenic or chronic tension-type headache. Previous gross anatomical and histologic studies only confirmed the existence of the MDB but did not reveal the fiber properties of the MDB. This is important to further mechanical and functional research on the MDB. Purpose Multiple histologic staining methods were used in the present study to reveal the various origin and fiber properties of the MDB. Muscles and ligaments participating in forming the MDB at the posterior atlanto-occipital or atlantoaxial interspaces were observed, and the fiber properties of the MDB were confirmed. The present study provides a basis for speculating the tensile force values of the MDB on the SDM and a morphologic foundational work for exploring the physiological functions and clinical significances of the MDB. Study Design Anatomical and histologic analyses of suboccipital structures that communicate with the SDM at the posterior atlanto-occipital or atlantoaxial interspaces were carried out. Methods Multiple histologic staining methods were used to evaluate the histologic properties and composition of the MDB at the posterior atlanto-occipital or atlantoaxial interspaces in five formalin-fixed head-neck human specimens. Results The results show that the MDB traversing the atlanto-occipital interspace originated from the rectus capitis posterior minor (RCPmi). The MDB traversing the atlantoaxial interspace originated mainly from the RCPmi, rectus capitis posterior major, and obliquus capitis inferior. These fibers form the vertebral dural ligament in the atlantoaxial interspace and connect with SDM. The MDB is mainly formed by parallel running type I collagen fibers; thus, suboccipital muscle could pull SDM strongly through the effective force propagated by the MDB during head movement. Conclusions Myodural bridge is mainly formed by parallel running type I collagen fibers; thus, it can transmit the strong pull from the diverse suboccipital muscles or ligaments during head movement. The results of the present study will serve as a basis for further biomechanical and functional MDB research.

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.

Background: There has been a lot of research on physical therapy for tension-type headaches. However, the efficacy of physical therapy on the suboccipital region remains unclear. Objective: To establish the effectiveness of physical therapy on the suboccipital area of patients with tension-type headache. Methods: Databases including Cochrane Library, Medline/Pubmed, CNKI, Embase, and Google Scholar were searched. After independent study selection by 2 authors, data were extracted and collected independently. On 1 hand, authors compared the treatment of the suboccipital area with control group. On the other hand, the efficacy of several physical therapy techniques on the suboccipital region was compared. The quality of the included studies was assessed using the Cochrane Handbook. RevMan 5.3 software was used for data analysis. The primary outcome measures were the cervical range of motion, the visual analog scale, and headache disability inventory. Results: Six randomized controlled trials with a total of 505 participants were included. Suboccipital soft-tissue inhibition technique (SIT) + occiput-atlas-axis global manipulation (OAA) was more effective than SIT in increasing craniocervical extension at 4 weeks post-treatment, the overall mean differences (MD) was 3.61, 95% confidence interval (CI) (0.89–6.34). There was no difference at 8 weeks post-treatment (MD 2.38, 95% CI −1.02 to 5.78, P = .17). SIT was more effective than SIT + OAA in increasing cervical flexion at 4-week post-treatment (MD −3.36, 95% CI −6.65 to −0.05). SIT + OAA was more effective than SIT on decreasing intensity of pain at 4-week post-treatment (MD −0.91, 95% CI −1.78 to −0.04), but no difference at 8-week (MD −0.43, 95% CI −1.18 to 0.33, P = .27). SIT + OAA was more effective than SIT in reducing the functional score of the headache disability inventory at 4-week post-treatment (MD −4.47, 95% CI −8.44 to −0.50). These results may indicate that the SIT + OAA combined therapy is more effective in short term (4-week), no major difference in longer term (8-week). Conclusion: Combined therapy may be more suitable for the treatment of tension-type headache.

The suboccipital muscles are connected to the upper cervical spinal dura mater via the myodural bridges (MDBs). Recently, it was suggested that they might work as a pump to provide power for cerebrospinal fluid (CSF) circulation. The purpose of this study was to investigate effects of the suboccipital muscles contractions on the CSF flow. Forty healthy adult volunteers were subjected to cine phase-contrast MR imaging. Each volunteer was scanned twice, once before and once after one-minute-head-rotation period. CSF flow waveform parameters at craniocervical junction were analyzed. The results showed that, after the head rotations, the maximum and average CSF flow rates during ventricular diastole were significantly increased and the CSF stroke volumes during diastole and during entire cardiac cycle were significantly increased. This suggested that the CSF flow was significantly promoted by head movements. Among the muscles related with head movements, only three suboccipital muscles are connected to the upper cervical spinal dura mater via MDBs. It was believed that MDBs might transform powers of the muscles to CSF. The present results suggested that the head movements served as an important contributor to CSF dynamics and the MDBs might be involved in this mechanism.

Objective We aimed to investigate the morphological changes and potential correlation between chronic headaches and the rectus capitis posterior minor muscle (RCPmi). Methods Comparison of RCPmi between patients with chronic headaches and healthy adult volunteers were collected using magnetic resonance imaging (MRI) and Mimics software. Results Among the 235 MRI images analyzed, the data between the two groups were considered statistically significant. The number of males was larger than that of females ( p Conclusions Chronic headaches were correlated with the RCPmi. Patients with chronic headaches suffered from more obvious hypertrophy than that of the control group. Additionally, it was supposed that RCPmi hypertrophy may be one pathogenesis of the chronic headaches.

This study evaluated the anatomical features of preseptal and preaponeurotic fat tissues in the upper eyelids of individuals of Asian heritage. Specifically, we attempted to elucidate the role of these tissues in the formation of sunken upper eyelids and devise an easy and feasible approach to rectify this. Sixteen heads (32 facial halves) from fresh adult cadavers were processed using the P45 plastination techniques. The polymer resulted in transparent plastination, and the sagittal median section of the eyeballs was dissected. Gross anatomy results of 12 adult cadaveric heads (24 facial halves) were included as supplementary data. The orbital septum was observed on sagittal section slides prepared with P45 sheet plastination. Based on the amount of fat distribution, the upper eyelid was classified into three groups: preseptal fat predominant type, preaponeurotic fat predominant type, and orbital septum equilibrium type (relative distribution of 31.3, 12.5, and 56.3 % in plastinated slices, and 29.2, 16.7, and 54.2 % in gross anatomical studies). Major tissues on P45 sheet plastination slices in the supraorbital region were preseptal fat, preaponeurotic fat, frontalis muscle and frontalis muscle aponeurosis, and partial orbicularis oculi muscle. The muscle fibers of the frontalis muscle and orbicularis oculi were interconnected and extended backward to connect with the orbital septum through preseptal fat. In conclusion, the morphology and external appearance of the upper eyelids depend on the relative relationship between preseptal and preaponeurotic fat tissues. Mildly or moderately sunken upper eyelids can be corrected by modifying the soft tissue in the supraorbital margin.

The myodural bridge was first described by Hack in 1995 and was thought to be related to chronic cervicogenic headaches. For a long time, few studies revealed the patterns of the myodural bridge considering the rectus capitis posterior minor muscle. In this study, P45 plastination technology and anatomical dissection were performed on head specimens, and four different terminal region types of the rectus capitis posterior minor muscle were observed, including the posterior atlanto-occipital interspace, posterior arch of the atlas and posterior atlanto-axial interspace. We propose that the myodural complex structures in the posterior atlanto-occipital and posterior atlanto-axial interspace have cooperative effects on cerebrospinal fluid and work together. This force might be an important source for the circulation of cerebrospinal fluid.

In the last two decades, many studies have focused on the muscles and dense connective tissues located in the suboccipital region. Our study investigated the existence of the second terminations originating from the suboccipital muscles, and the relationship between the variable types of the To Be Named Ligament (TBNL). Anatomical dissection was performed on 35 head-neck specimens. The existence of the second terminations of the suboccipital muscles was confirmed and various types of the TBNL were observed in this study. The second terminations originated from multiple suboccipital muscles including the rectus capitis posterior minor (RCPmi), rectus capitis posterior major (RCPma) and obliquus capitis inferior (OCI) muscles, merged and terminated at the TBNL. The overall incidence of the second terminations of the suboccipital muscles was 34.29% and it varied among the various suboccipital muscle origins. 28.57% of the second terminations originated from the RCPma; 11.43% was from the RCPmi and 8.57% was from the OCI. Furthermore, there was a significant relationship between the existence of second terminations and the particular type of the TBNL. 95% of the arcuate type of the TBNL was accompanied with the second terminations which attached to their turning part, whereas only 10% of all the radiate type of the TBNL was accompanied with the second terminations. This study for the first time described the second terminations originating from multiple suboccipital muscles and demonstrated the relationship with the various types of the TBNL. We speculated that the second terminations maintain the arcuate TBNL and transfer tensile forces to the Myodural Bridge (MDB), thereby modulating the physiological functions of the MDB.

Few studies have been conducted specifically on the dense connective tissue located in the posterior medial part of the cervical epidural space. This study was undertaken to examine the presence of this connection between the cervical dura mater and the posterior wall of spinal canal at the level of C1-C2. 30 head-neck specimens of Chinese adults were used. Gross dissection was performed on the suboccipital regions of the 20 specimens. Having been treated with the P45 plastination method, 10 specimens were sliced (9 sagittal and 1 horizontal sections). As a result, a dense fibrous band was identified in the nuchal ligament of 29 specimens (except for one horizontal section case). This fascial structure arose from the tissue of the posterior border of the nuchal ligament and then projected anteriorly and superiorly to enter the atlantoaxial interspace. It was termed as to be named ligament (TBNL). In all 30 specimens the existence of a fibrous connection was found between the posterior aspect of the cervical dura mater and the posterior wall of the spinal canal at the level of the atlas to the axis. This fibrous connection was identified as vertebrodural ligament (VDL). The VDL was mainly subdivided into three parts, and five variations of VDL were identified. These two structures, TBNL and VDL, firmly link the posterior aspect of cervical dura mater to the rear of the atlas-axis and the nuchal region. According to these findings, the authors speculated that the movements of the head and neck are likely to affect the shape of the cervical dural sleeve via the TBNL and VDL. It is hypothesized that the muscles directly associated with the cervical dural sleeve, in the suboccipital region, may work as a pump providing an important force required to move the CSF in the spinal canal.

With the development of hepatic surgery and radiology, an increasing amount of researchers have reported discrepancies between the real distribution of the hepatic portal vein branches and Couinaud's segmentation, especially for further division of the right medial division. The present study investigated 25 cadaveric liver dissections and 30 three-dimensional reconstruction images of intrahepatic vessels. The ramifications, course, distribution and quantity of the portal branches were analyzed. An oblique fissure that had few vessels was found among third-order branches of the hepatic portal vein of the right medial division. The right medial division could be redivided into the ventral subsegment and dorsal subsegment by this oblique fissure. A hepatic vein coursed in the oblique fissure between the ventral subsegment and dorsal subsegment. The hepatic vein could serve as an anatomical landmark of the inter-subsegmental plane. This new method of identifying further division of the right medial division is a novel concept providing further information on conventional segmental anatomy. Clin. Anat. 25:489–495, 2012. © 2011 Wiley Periodicals, Inc.

To compare the areas of human liver horizontal sections with computed tomography (CT) images and to evaluate whether the subsegments determined by CT are consistent with the actual anatomy. Six human cadaver livers were made into horizontal slices with multislice spiral CT three-dimensional (3D) reconstruction was used during infusion process. Each liver segment was displayed using different color, and 3D images of the portal and hepatic vein were reconstructed. Each segmental area was measured on CT-reconstructed images, which were compared with the actual area on the sections of the same liver. The measurements were performed at four key levels namely: (1) the three hepatic veins, (2) the left, and (3) the right branch of portal vein (PV), and (4) caudal to the bifurcation of the PV. By dividing the sum of these areas by the total area of the liver, the authors got the percentage of the incorrectly determined subsegmental areas. In addition to these percentage values, the maximum distances of the radiologically determined intersegmental boundaries from the true anatomic boundaries were measured. On the four key levels, an average of 28.64 ± 10.26% of the hepatic area of CT images was attributed to an incorrect segment. The mean-maximum error between artificial segments on images and actual anatomical segments was 3.81 ± 1.37 cm. The correlation between radiological segmenting method and actual anatomy was poor. The hepatic segments being divided strictly according to the branching point of the PV could be more informative during liver segmental resection.

Until now there has been no definitive anatomical study of the boundary between hepatic subsegments IVa and IVb. In this study, we used a multicolor segmental corrosion cast technique and a multicolor segmental technique on plastinated slices, in combination with helical CT three-dimensional (3D) reconstruction on 15 donated fresh isolated human liver specimens. The corrosion cast technique was carried out on eight of these specimens, and the remaining seven livers were used to make horizontal plastinated slices. Examination of these specimens and observation of 20 additional liver corrosion cast specimens showed that all boundaries between hepatic segments were complex, undulating scissures rather than simple, flat planes. We also found that there was an obvious boundary between subsegments IVa and IVb, such that subsegment IVa laid posterosuperior to subsegment IVb. A tributary of a hepatic vein passed through the boundary between subsegments IVa and IVb, and could serve as an anatomical landmark of this boundary. Clin. Anat. 21:439–446, 2008. © 2008 Wiley-Liss, Inc.

Thirty-three linear measurements and two ratios were derived from 102 12th thoracic vertebrae of the Digital Korean database at the Catholic Institute for Applied Anatomy. Of 35 linear traits, 23 were sexually dimorphic. We created 23 discriminant function equations that predicted sex with 62.7-85.3% accuracy. The analysis using combinations of two factors gave higher accuracies: most equations with accuracies over 80% included at least one measurement involving the coronal diameter of the vertebral endplate. Using stepwise method of discriminant function analysis, three variables predicted sex with 90.0% accuracy: the coronal diameter of the superior endplate of the vertebral body, the ratio of anterior to middle height of the body, and the length of the left mammillary process and pedicle. Coronal dimensions of the vertebral body represented the major sex difference. These equations will help forensic discrimination of the sex of this vertebra among Koreans.

The anatomic features of transsphenoidal approach are reviewed, focusing on the microsurgical anatomy of suprasellar and parasellar structures. Pertinent microsurgical anatomy is described for neurosurgeons to successfully extend a standard transsphenoidal approach for treatment of lesions including the region of the tuberculum sellae, planum sphenoidale, supradiaphragmatic intradural space, and medial cavernous sinus.15 specimens (30 sides) from formalin fixed cadaveric heads and 20 adult dry skulls (40 sides) were observed. According to the need for the extend transsphenoidal approach, the sellar and parasellar region: the planum sphenoidale and the supradiaphragmatic area, medial part of cavernous sinus were studied. Special emphases were put on the relation of the cranial nerve and blood vessel structures surrounding the sellar. Meanwhile, we made the cast specimen of the blood vessel and studied the structure character of the internal carotid artery in the cavernous sinus.Posterior ethmoidal could be exit as para or suprasphenoidal ethmoidal air cell. It will be important for extending the transsphenoidal approach. The mean distance between two optic canal is 15.7 +/- 3.2 mm (11.0 - 18.0 mm), the distance of internal carotid artery at tuberculum cellae level is 13.9 +/- 3.8 mm (10.0 - 17.0 mm), the mean distance between tuberculum cellae and the posterior rim of cribriform plate is 23.3 +/- 3.2 mm, the included angle between sagittal plane and optic canal is 36.3 degrees +/- 1.6 degrees , with the anatomy research data give the clue that the bone window should be made as the shape of "[see text]".Expending transsphenoidal approach is suitable for medium and small lesions growing along the centre line which expand to para sellar, anterior sellar and sphenoid platform. That hypophysis has close relation with internal carotid artery during expending transsphenoidal approach to cavernous sinus increase the risk of operation. The carotid artery and abducent nerve are the easiest structures to be damaged during the operation.