Morphological divergence in the curvature of human femoral diaphyses: Tracing the central mass distributions of cross-sections.

The diaphysis of the human femoral bone has a physiological anterior curvature; additionally, there is a curvature to the medial side or lateral side. In addition to compression stress from gravity during standing, walking, and running, these bones are continuously exposed to complex stresses from the traction forces of the various strong muscles attached to them. The femoral diaphysis is subjected to these mechanical stresses, and the direction and size of its curvature are defined according to Wolff's law and the mechanostat theory of Frost. The purpose of this study was to quantitatively evaluate the curvature of the femoral diaphysis in Japanese skeletons by determining the curve connecting the central mass distributions (CMD) of cross-sectional images. A total of 90 right femora (46 males and 44 females) were randomly selected from modern Japanese skeletal specimens. Full-length images of these bones were acquired using a clinical computed tomography scanner. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain ten planes, and nine levels were analyzed. The CMD curve was determined by connecting the CMDs of each of the nine cross-sections. First, the CMD of a cross-section in each of the nine slices was calculated, and the nine trajectories were superimposed from above. Then, by converting the shape of the entire CMD curve to superimpose the coordinates of the endpoint on the starting point, a closed arc representing the curvature of the femur was determined. For both males and females, the patterns varied from mostly medial to largely lateral curvature. The size of the curvature also varied for individuals. By analyzing only the coordinates of the vertex of the CMD curve of each femoral bone, the outlines of the diaphyseal curvatures could be recognized. The femora were thereby divided into two groups: medial bending and lateral bending. Considering males and females together, the number in the lateral-curvature group (n = 51) was larger than that in the medial-curvature group (n = 39). Moreover, the average age of the lateral-curvature group was significantly higher than that of the medial-curvature group (p < 0.05). In males, with an increase in the cortical bone proportion of the cross-sectional area, the anterior vertex of diaphyseal bending tended to be more prominent. This cortical proportion was significantly higher in the medial-curvature groups than in the lateral-curvature group (p < 0.01). The phenomena observed in this study may be related to pathophysiologies such as atypical fractures of the femur and osteoarthritis of the knee joints.

Morphological profile of atypical femoral fractures: age-related changes to the cross-sectional geometry of the diaphysis.

The use of bisphosphonates for osteoporosis patients has markedly decreased the incidence of femoral neck or trochanteric fractures. However, anti-osteoporosis drugs have been reported to increase the incidence of atypical femoral fractures, which involve stress fractures in the subtrochanteric region or the proximal diaphysis. In this study, the morphological characteristics of the cortical bone in human femoral diaphysis samples were analyzed from individuals who lived before bisphosphonate drugs were available in Japan. A total of 90 right femoral bones were arbitrarily selected (46 males and 44 females) from modern Japanese skeletal specimens. Full-length images of these femurs were acquired using a computed tomography scanner. An image processing method for binarization was used to calculate the threshold values of individual bones for determining their contours. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain 10 planes. The mean value of cortical bone thickness, periosteal border length, and the cortical cross-sectional area was evaluated for all planes. Moreover, the ratio of the area of the cortical bone to the total area of cross-section at the mid-diaphysis was calculated. A comparison between males and females demonstrated that most females had lower cortical bone area ratios at the mid-diaphysis. The femoral outer shape did not differ markedly according to age or sex; however, substantial individual differences were observed in the shape of the inner surface of the cortical bone. The cortical bone thickness and the cross-sectional area decreased with age in the femoral diaphysis; furthermore, in females, the decrease was higher for the former than for the latter. This may be due to a compensatory increase in the circumference of the femoral diaphysis. In addition, in about half of the subjects there was a discrepancy between the region with maximal value of the cortical bone thickness and that of the total cross-sectional area. Biological responses to mechanical stresses to the femoral diaphysis are thought not to be uniform. Bisphosphonates inhibit bone resorption and may promote non-physiological bone remodeling. Thus, a nonhomogeneous decrease in cortical thickness may be related to the fracture occurrence in the femoral diaphysis in some cases. Thus, long-term administration of bisphosphonates in patients with morphological vulnerability in the femoral cortical bones may increase the occurrence of atypical femoral fractures.

Three-dimensional morphological analysis of the human sacroiliac joint: influences on the degenerative changes of the auricular surfaces.

The sacroiliac joint (SIJ) is responsible for weight transmission between the spine and lower extremity. However, details of the structure and function of the SIJ remain unclear. In a previous study, we devised a method of quantitatively evaluating the level of degeneration of the SIJ using an age estimation procedure for the auricular surface of the ilium. Our results in that study suggested that the degree of degeneration of the joint surface may be associated with the morphology of the auricular surface of the ilium. In that study, however, the morphology of the auricular surface of the ilium was simplified for analysis, meaning that more detailed investigations were required in future. In the present study, we focused on individual differences in the shape of SIJ and carried out three-dimensional quantitative evaluation of the morphology of the auricular surface of the ilium to ascertain its association with joint degeneration. We produced three-dimensional images of the right auricular surfaces of the ilium of 100 modern Japanese men (age 19-83), and obtained the three-dimensional rectangular coordinates of 11 defined measurement points. We then calculated 16 parameters indicating the morphological characteristics of the auricular surfaces of the ilium from the three-dimensional rectangular coordinates of these measurement points, and used these to perform principal component analysis to investigate trends in the morphology of the auricular surface of the ilium. We found that the morphology of the auricular surface of the ilium could be characterized in terms of (i) size, (ii) concavity of the posterior border and (iii) amount of undulation. An investigation of the correlation between these parameters and age suggested that the amount of undulation of the auricular surface of the ilium tends to diminish with advancing age. In an investigation of the association between morphology of the auricular surface of the ilium and degeneration of the articular surface when the subjects were divided into a high-degeneration group (n = 55) and a low-degeneration group (n = 45) and the 16 parameters were compared, there was a significant difference in the amount of undulation of the auricular surface of the ilium. In an investigation limited to older subjects aged ≥ 60 (n = 47) at the time of death, there were significant differences between the high-degeneration group (n = 27) and low-degeneration group (n = 20) in terms not only of the parameters indicating the amount of undulation of the auricular surface of the ilium but also of those indicating the amount of the concavity of the posterior border. These results suggested that the amount of undulation of the auricular surface of the ilium may affect the degree of degeneration of the articular surface. In addition, in older subjects, the degree of concavity of the posterior border of the SIJ may also affect the degree of degeneration of the articular surface. It is thus likely that differences in the morphology of the auricular surface of the ilium may affect degenerative changes in the SIJ.

Somatosensory cortex excitability changes due to differences in instruction conditions of motor imagery.

Purpose Vivid motor imagery appears to be associated with improved motor learning efficiency. However, the practical difficulties in measuring vivid motor imagery warrant new analytical approaches. The present study aimed to determine the instruction conditions for which vividness in motor imagery could be more easily seen and the excitability of the sensory cortex as it relates to the motor image. Materials and methods In total, 15 healthy, right-handed volunteers were instructed to imagine grasping a rubber ball under a verbal-only instruction condition (verbal condition), a verbal + visual instruction condition (visual condition), and a verbal + execution (physically grasping a real ball) condition (execution condition). We analyzed motor imagery-related changes in somatosensory cortical excitability by comparing somatosensory-evoked potentials in each condition with the rest (control) condition. We also used a visual analogue scale to measure subject-reported vividness of imagery. Results We found the N33 component was significantly lower in the execution condition than in the rest condition (p < 0.05). The results suggested a gating effect via central efferent mechanisms that affected the excitability of areas 3b or 1 in the primary somatosensory cortex, but only in the execution condition. Conclusions These data suggest that experiencing a movement through actual motor execution immediately prior to performing mental imagery of that movement enhances the excitability of motor-related cortical areas. It is suggested that the excitability of the motor-related region increased as a result of the motor imagery in the execution condition acting on the corresponding somatosensory cortex.

Mirror Therapy Reduces Pain and Preserves Corticomotor Excitability in Human Experimental Skeletal Muscle Pain.

Approaches to preserve corticomotor excitability (CE) are attracting interest as a treatment for pain-induced changes in neural plasticity. We determined the effects of mirror therapy (MT) on skeletal muscle pain. Fifteen healthy adults who received hypertonic saline injections (5.8% NaCl, 0.2 mL) into the first dorsal interosseous (FDI) muscle of the right hand to induce experimental skeletal muscle pain were assigned to either the "MT and injection" or "injection only" group. Post-injection, the "MT and injection" group observed their left index finger abducting and adducting for 4 min, creating the illusion that the right index finger was moving. The "injection only" group remained at rest. CE and pain were assessed by measuring motor-evoked potentials (MEPs) of the right FDI triggered by transcranial magnetic stimulation and the numerical rating scale (NRS), respectively. MEP amplitudes were significantly higher in the "MT and injection" group, a trend that persisted post-MT intervention (MT intervention; p < 0.01, post-1; p < 0.05). The time for the NRS score to reach 0 was notably shorter in the "MT and injection" group (p < 0.05). Our preliminary results suggested that MT decreases CE and pain in skeletal muscles, potentially preventing neural plasticity changes associated with skeletal muscle pain and providing early pain relief.

Cross-sectional geometry of the femoral diaphyseal cortical bones: analysis of central mass distribution.

A detailed analysis of differences in skeletal shape among many individuals is expected to reveal the mechanical significance behind various morphological features. To confirm the distribution of the cortical bone region in cross sections, the relative position of the central mass distribution (CMD) of the cortical bone region to the CMD of the entire cross section was examined. A total of 90 right human femoral skeletons were examined using clinical multi-slice computed tomography. For nine cross sections of each femur, we determined the CMD of the whole area, including both cortical bone and medullary areas, as CMD-W, and that of the cortical bone region in the same cross section as CMD-C, and they were compared. The medial and anterior portion of the cortex was relatively thick just below the lesser trochanter. The posterior cortical bone tended to be relatively thick in the region from the center to the distal part of the diaphysis. Females had a significantly more medially deviated CMD than males throughout the entire diaphysis. These results suggest that femurs with advanced cortical bone thinning tend to have a concentration of cortical bone in their medial portion. CMD-C was located farther from the diaphysis axis as the degree of medial bending increased. Conversely, the greater the lateral bending of the diaphysis, the closer CMD-C was to the diaphysis axis. As the amount of bone decreases with age, self-adjustment could occur so that the cortical bone's critical area remains to prevent a decrease in mechanical strength.

Similarities and Differences in Bone Mineral Density between Multiple Sites in the Same Individual: An Elderly Cadaveric Study.

Bone mineral density (BMD) is known to vary based on various factors, and the degree of variation is site-specific. However, few studies have investigated the relationship between bone density at trabecular bone-rich and cortical bone-rich sites in the same individual. In this study, we attempted to measure BMD at multiple sites using whole-body computed tomography images taken immediately after death and to clarify the similarities and differences between skeletal sites. Additionally, we aimed to examine the factors that influence changes in BMD, such as the loading environment, bone microstructure, and the ossification process of each skeletal region. A 3D model containing BMD data of the skull, clavicle, lumbar vertebrae, and femur (neck and diaphysis) was created using computed tomography images taken immediately after the death of 60 individuals (28 men and 32 women, average age: 84.0 years) who consented to participate in the study before death. Arbitrary measurement sites were defined, and bone density was measured at each site. We found that the BMDs of all regions were negatively correlated with age, but this correlation was weaker in the skull than in other regions. The negative correlation was especially pronounced in areas with more trabecular bones in men and in areas with more cortical bones in women. Furthermore, these findings suggest that factors, such as the loading environment, bone microstructure, and the ossification process of the skeletal sites, affect the BMD. Furthermore, our results suggest that it is important to assess the BMD of cortical bone in older women.

Effects of attentional bias modification on chronic low back pain in older outpatients: A randomized crossover trial (pilot study).

OBJECTIVES: In the present study, the effect of attentional bias modification (ABM) on older outpatients, with chronic low back pain, was examined. DESIGN: This was a single-center, randomized, single-blinded, crossover trial and patients were randomly divided in a 1:1 allocation ratio into two groups: an ABM Leading group and an ABM Trailing group. PARTICIPANTS: Forty-three outpatients with chronic low back pain participated. INTERVENTIONS: Patients were evaluated four times and the treatments were ABM + Normal intervention or Normal intervention only. OUTCOMES: Outcome measures included pain intensity on the Numerical Rating Scale, the Pain Catastrophizing Scale, Fear-Avoidance Beliefs Questionnaire, Hospital Anxiety and Depression Scale, Somatic Symptom Scale-8, and EuroQol 5 Dimension-3 levels questionnaire. In addition, we performed the 30-second Chair-Stand test and the Timed Up & Go test for physical function evaluations. RESULTS: There was no change in pain intensity due to ABM. However, the total Pain Catastrophizing Scale score was significantly decreased, and the EuroQol 5 Dimension-3 levels questionnaire and 30-second chair-stand test were significantly improved (P <.05). TRIAL REGISTRATION: The Health Science Ethics Committee, Graduate School of Biomedical Sciences, Nagasaki University (permit number: 17060861), and the clinical trial was registered with UMIN (UMIN000029424).

Significant Asymmetry of the Bilateral Upper Extremities of a Skeleton Excavated from the Mashiki-Azamabaru Site, Okinawa Island, Japan.

The human skeleton of a young adult male with marked asymmetry of the bilateral upper extremities was excavated from the Mashiki-Azamabaru site (3000-2000 BCE) on the main island of Okinawa in the southwestern archipelago of Japan. The skeleton was buried alone in a corner of the cemetery. In this study, morphological and radiographic observations were made on this skeleton, and the pathogenesis of the bone growth disorder observed in the left upper limb was discussed. The maximum diameter of the midshaft of the humerus was 13.8 mm on the left and 21.2 mm on the right. The long bones comprising the left upper extremity lost the structure of the muscle attachments except for the deltoid tubercle of the humerus. The bone morphology of the right upper extremity and the bilateral lower extremities was maintained and was close to the mean value of females from the Ohtomo site in northwestern Kyushu, Japan, during the Yayoi period. It is assumed that the anomalous bone morphology confined to the left upper extremity was secondary to the prolonged loss of function of the muscles attached to left extremity bones. In this case, birth palsy, brachial plexus injury in childhood, and acute grey matter myelitis were diagnosed. It was suggested that this person had survived into young adulthood with severe paralysis of the left upper extremity due to injury or disease at an early age.

Gross anatomical investigation of the muscular head between the vastus lateralis and intermedius in the Japanese population: a cadaver study.

Unlike the general understanding of the quadriceps femoris, the existence of a new muscular head between the vastus lateralis and the vastus intermedius was reported, and named the tensor of the vastus intermedius in the Swedish population. The purpose of this study was to investigate the presence and form of the muscular head in the Japanese population and to clarify its structure by gross anatomical approaches. A total of 35 thighs of 20 Japanese cadavers were investigated. We searched for the muscular head and classified it into four types. In addition, nerve fiber analysis was performed for each classification type. Regarding classification, 11% were the independent type, 29% were the common type, 37% were the vastus lateralis type, and 23% were the vastus intermedius type. Based on nerve fiber analysis, in the common type, the muscular head was under dual nerve supply from the vastus lateralis and intermedius. The other three types were innervated only by nerves from the vastus lateralis. The target muscular head may always be present in Japanese. The nerves from the vastus lateralis were always distributed in the target muscular head based on nerve fiber analysis; therefore, this muscular head may be most closely related to the vastus lateralis. The name of this muscular head should be "the accessory head of the vastus lateralis" rather than "the tensor of the vastus intermedius."

The Vividness of Motor Imagery Is Correlated With Corticospinal Excitability During Combined Motor Imagery and Action Observation.

The present study aimed to investigate the relationship between motor imagery (MI) assessment (ability and quality) and neurophysiological assessment [transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEPs)] during combined MI and action observation (AO; MI + AO). Sixteen subjects completed an MI task playing the piano with both hands, and neurophysiological assessment was performed during the MI task. The Movement Imagery Questionnaire-Revised was adopted to evaluate MI ability, while the visual analogue scale (VAS) was adopted to evaluate MI quality. A TMS pulse was delivered during the MI task, and MEPs were subsequently recorded in the abductor pollicis brevis (APB). We found a significant positive correlation between the VAS score and the TMS-induced MEPs (ρ = 0.497, p < 0.001). These findings suggest that the VAS score could potentially reflect the corticospinal excitability during MI + AO, particularly in complex MI tasks.

Sex-based differences in human sacroiliac joint shape: a three-dimensional morphological analysis of the iliac auricular surface of modern Japanese macerated bones.

The human pelvis is one of the skeletons where sex differences are expressed, but few detailed studies have been conducted on sex-related differences in the sacroiliac joint morphology. Therefore, we conducted a three-dimensional morphological analysis evaluation of the sacroiliac joints to clarify the sex-related difference of the joint's morphology. Right-side macerated innominate bones of Japanese males (n = 100) and females (n = 70) whose ages at death were recorded were included in the study. Three-dimensional images were created from the subjects' iliac auricular surface images, and 16 measurement parameters were acquired on the basis of 11 defined measurement points. All measurement parameters were compared between the male and female groups. The values of the measurement parameters indicating the size of the iliac auricular surface were significantly larger in the male group than in the female group. In addition, the angle between the short and long arms of the auricular surface was larger in the male group. Furthermore, on the basis of the corrected values of the physical disparity, the long arm dimension of the iliac auricular surface was larger in the male group, while the short arm dimension was larger in the female group. The sex-based differences in the iliac auricular surface morphology that were confirmed in this study may reflect the sex-based differences in the sacroiliac joint function. The findings of this study may contribute to the elucidation of the pathophysiology of the sacroiliac joint dysfunction that frequently occurs in women.

Double-sided superior vena cava: developmental considerations associated with the thymic veins / Vena cava superior de doble cara: consideraciones de desarrollo asociadas con las venas tímicas

SUMMARY: The superior vena cava is usually located only on the right side, but persistence of the left superior vena cavais observed in about 0.3 to 0.5 % of adults. A routine dissection of the cadaver of a 91-year-old Japanese female, whose cause of death was sepsis due to cholecystitis, was performed at Nagasaki University and revealed a double-sided superior vena cava. On the right side, the superior vena cava opened to the right atrium, while on the left, it opened into the extended coronary sinus. Veins in the left head, neck and upper limb regions joined to form the persistent left superior vena cava, with eventual drainage into the expanded coronary vein. An anastomosing branch occurred between each superior vena cava, and two thymic veins opened to the anastomosing branch. The azygos vein in the azygos venous system opened into the right superior vena cava, whereas a hemi-azygos vein opened into the azygos vein. The accessory hemi-azygos vein also opened into the azygos vein and opened cranially into the left superior vena cava. The left supreme intercostal vein also opened into the left superior vena cava. Several studies have reported a persistent left superior vena cava and the various considerations for its occurrence. Here, we propose a new hypothesis for the embryonic development of the persistent left superior vena cava with the thymic vein. This hypothesis essentially states that the left brachiocephalic vein fails to mature due to inadequate venous return from the thymic vein during the embryonic period, and the left superior vena cava then remains to maintain venous return from the left head, neck and upper limb. We also discuss the clinical significance of the persistent left superior vena cava.

RESUMEN: Usualmente la vena cava superior se localiza solo en el lado derecho, sin embargo en aproximadamente 0,3 a 0,5 % de los adultos se observa la persistencia de la vena cava superior izquierda. En la Universidad de Nagasaki se realizó una disección de rutina del cadáver de una mujer japonesa de 91 años, cuya causa de muerte fue sepsis debido a una colecistitis. El cuerpo presentaba una vena cava superior doble. En el lado derecho, la vena cava superior llegaba al atrio derecho, mientras que en el lado izquierdo drenaba al seno coronario. Las venas de las regiones de la cabeza, el cuello y del miembro superior izquierdo formaban la vena cava superior izquierda persistente, con drenaje hacia la vena coronaria. Se observó una rama anastomótica entre cada vena cava superior y dos venas tímicas drenaban a la rama anastomótica. La vena ácigos drenaba a la vena cava superior derecha, mientras que una vena hemiácigos drenaba a la vena ácigos. La vena hemiácigos accesoria también drnaba en la vena ácigos y cranealmente lo hacia la vena cava superior izquierda. La vena intercostal suprema izquierda drenaba en la vena cava superior izquierda. Varios estudios han informado una vena cava superior izquierda persistente y las diversas consideraciones para su aparición. Aquí, proponemos una nueva hipótesis para el desarrollo embrionario de la vena cava superior izquierda persistente con la vena tímica, que esencialmente establece que la vena braquiocefálica izquierda no se dearrolla debido a un retorno venoso inadecuado de la vena tímica durante el período embrionario, y se mantiene la vena cava superior izquierda para el retorno venoso de la cabeza, el cuello y el miembro superior izquierdo. Además se informa de la importancia clínica de la persistencia de la vena cava superior izquierda.

Degenerative changes of the sacroiliac auricular joint surface-validation of influential factors.

The purpose of this study was to clarify the relevance of degenerative changes in the sacroiliac joint (SIJ) and the joints in the lower limb and lumbar spine using age estimation methods. We also examined the shape of the auricular surface to determine the effect of degenerative changes on each joint. A total of 200 iliac auricular surfaces from 100 Japanese male skeletons were examined macroscopically in accordance with conventional methods of age estimation. From the obtained estimated age, we calculated the deflection values, which represented the degree of degenerative changes of the joints. For comparison, we used osteophyte score data of the hip, knee, and zygapophyseal joints in lumbar spines from previous studies which had used the same bone specimens. As a quantitative indicator of auricular surface morphology, we defined the constriction ratio (CR) of the auricular surface and compared the CR values obtained with various measured values. Degenerative changes in the SIJ were positively correlated with those in both the hip joint and zygapophyseal joint, but a correlation with knee joints was found only on the left side. In skeletons from individuals aged ≥60 years as time of death, the CR was significantly different between the group with high scores and those with low scores in both the hip and sacroiliac joints. It has been suggested that degenerative changes in SIJs interact with those in the hip joint and zygapophyseal joint. In addition, the shape of the auricular surface may also be a relevant factor for degenerative changes in these joints.

Primary Motor Cortex Activation during Action Observation of Tasks at Different Video Speeds Is Dependent on Movement Task and Muscle Properties.

The aim of the present study was to investigate how the video speed of observed action affects the excitability of the primary motor cortex (M1), as assessed by the size of motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS). Twelve healthy subjects observed a video clip of a person catching a ball (Experiment 1: rapid movement) and another 12 healthy subjects observed a video clip of a person reaching to lift a ball (Experiment 2: slow movement task). We played each video at three different speeds (slow, normal and fast). The stimulus was given at two points of timing in each experiment. These stimulus points were locked to specific frames of the video rather than occurring at specific absolute times, for ease of comparison across different speeds. We recorded MEPs from the first dorsal interosseous muscle (FDI) and abductor digiti minimi muscle (ADM) of the right hand. MEPs were significantly different for different video speeds only in the rapid movement task. MEPs for the rapid movement task were higher when subjects observed an action played at slow speed than normal or fast speed condition. There was no significant change for the slow movement task. Video speed was effective only in the ADM. Moreover, MEPs in the ADM were significantly higher than in the FDI in a rapid movement task under the slow speed condition. Our findings suggest that the M1 becomes more excitable when subjects observe the video clip at the slow speed in a rapid movement, because they could recognize the elements of movement in others. Our results suggest the effects of manipulating the speed of the viewed task on the excitability of the M1 during passive observation differ depending on the type of movement task observed. It is likely that rehabilitation in the clinical setting will be more efficient if the video speed is changed to match the task's characteristics.