Does 20 Hz Transcranial Alternating Current Stimulation over the Human Primary Motor Cortex Modulate Beta Rebound Following Voluntary Movement?

Beta frequency oscillations originating from the primary motor cortex increase in amplitude following the initiation of voluntary movement, a process termed beta rebound. The strength of beta rebound has been reported to predict the recovery of motor function following stroke, suggesting therapeutic applications of beta rebound modulation. The present study examined the effect of 20 Hz transcranial alternating current stimulation (tACS) on the beta rebound induced by self-paced voluntary movement. Electroencephalograms (EEGs) and electromyograms (EMGs) were recorded from 16 healthy adults during voluntary movements performed before and after active or sham tACS. There was no significant change in average beta rebound after active tACS. However, the beta rebound amplitude was significantly enhanced in a subset of participants, and the magnitude of the increase across all participants was negatively correlated with the difference between individual peak beta frequency and tACS frequency. Thus, matching the stimulus frequency of tACS with individual beta frequency may facilitate therapeutic enhancement for motor rehabilitation.

Leg Cycling Leads to Improvement of Spasticity by Enhancement of Presynaptic Inhibition in Patients with Cerebral Palsy.

OBJECTIVE: The purpose of this study was to investigate if leg cycling could reduce lower extremity spasticity in patients with cerebral palsy (CP). In addition, we investigated whether the intervention could cause changes in the modulation of presynaptic inhibition. METHODS: This study was a quasi-experimental study, with pretest-posttest for 1 group. Participants in this experiment were eight adult patients with CP with lower extremity spasticity. Spasticity parameters assessed were the amplitude of soleus maximum Hoffmann's reflex (Hmax) and maximum angular velocity (MAV) of knee flexion measured using the pendulum test. D1 inhibition, which seems to be related to the presynaptic inhibition, was recorded by measuring soleus Hoffmann's reflex (H-reflex) with conditioned electric stimuli to the common peroneal nerve. RESULTS: D1 inhibition was significantly enhanced immediately by the cycling intervention. The amplitude of the soleus Hmax was significantly depressed, and there was significant difference in Hmax/maximum M-wave. The MAV was increased due to inhibition of the stretch reflex. CONCLUSION: Leg cycling suppressed stretch reflex and H-reflex, and caused plasticity of inhibitory circuits in patients with CP with lower extremity spasticity. These findings strongly suggest that lower extremity spasticity can be improved by cycling movements.

Physical activity is associated with walking and balance ability but not fatigue, knee extension strength, or body composition in adults with cerebral palsy: a pilot cross-sectional study.

Common secondary impairments associated with aging in adults with cerebral palsy (CP) decrease physical functions, including walking and balance ability, and increase the sense of fatigue. This motor dysfunction results in decreased physical activity (PA) and could be associated with obesity and sarcopenia. This study examined the association of daily PA levels with fatigue, physical function, and body composition in 22 adults with CP (age, 37.4 ±â€…14.7 years; Gross Motor Function Classification System level, I: 6, II: 16). The level of daily PA was divided into percent of sedentary behavior, light PA, and moderate-to-vigorous PA (%MVPA) per day. These outcomes were examined for correlation with the Fatigue Severity Scale, knee extension strength, comfortable and maximum walking speed, Timed-Up-and-Go-Test (TUG), and body fat percentage and skeletal muscle mass using Spearman's rank correlation coefficient. An additional partial correlation analysis with sex and age adjustment was performed. The %MVPA correlated positively with comfortable walking speed (rs = 0.424, P  = 0.049) and negatively with TUG (rs = -0.493, P  = 0.020). The partial correlation revealed associations of %MVPA with maximum walking speed (r = 0.604, P  = 0.022) and TUG (r = -0.604, P  = 0.022). The results show that among adults with CP, increased PA is associated with improvements in mobility but not in perceived fatigue or body composition, regardless of sex and age. Maintaining and improving %MVPA and walking and balance ability in adults with CP have a positive impact on each other, and potentially on overall health management.

Developmental changes in straight gait in childhood.

BACKGROUND: Understanding typical gait development is critical in developing suitable physical therapy methods for gait disorders. This study investigated the developmental changes and controlling mechanisms of straight gait. METHODS: We conducted an experimental procedure among 90 participants, including 76 typically developing children and 14 healthy adults. The children were divided according to age into 3-4, 5-6, 7-8, and 9-10-year age groups. We created two indices to quantify straight gait using the extrapolated center of mass (XCOM; goal index, XCOMG and actual progress index, XCOMP), which were calculated and compared between the groups. Stepwise multiple regression was used to examine the effects of each gait variable on XCOMG and XCOMP. To eliminate the effects of multicollinearity, correlation coefficients were calculated for all gait variables. RESULTS: Both XCOMG and XCOMP decreased gradually with age and were significantly larger in the 3-4 and 5-6 year groups than in the adult group. Multiple regression analysis showed that step velocity, step width, and the coefficiente of variation (CV) of the step width had independent coefficients of variation for the XCOMG, and the symmetry index of step time, step width, and the CV of the step width had independent CV for the XCOMP. These variables were selected as significant variables. The results showed that meandering gait was more pronounced at younger ages. Furthermore, straight gait observed in adulthood was achieved by the age of 7. CONCLUSION: Pace (step velocity) and stability (step width and CV of step width) may contribute to XCOMG, which assesses the ability to proceed in the direction of the target. Stability and symmetry may contribute to XCOMP, which assesses the ability to walk straight in one's own direction of progress. Physical therapists could apply these indices in children to assess their ability to walk straight.

Effects of Fear of Falling on the Single-Step Threshold for Lateral Balance Recovery in Older Women.

BACKGROUND AND PURPOSE: Fear of falling is associated with poor physical health and influences postural stability during whole-body movement. The ability to recover from lateral balance loss is required to prevent falls; however, the relationship between lateral balance recovery and fear of falling has not been established. This study aimed to investigate whether fear of falling is associated with the stepping threshold for lateral balance recovery. METHODS: This study included 56 ambulatory, community-dwelling women aged 65 years or older. We determined the single-step threshold as the maximum lean magnitude normalized with body weight from which participants could be suddenly released and still recover balance using a single side step. The short-form Falls Efficacy Scale International was used as a measure of fear of falling. RESULTS AND DISCUSSION: The single-step threshold significantly correlated with age ( rs =-0.603) and the short-form Falls Efficacy Scale International score ( rs =-0.439). Ordinal regression analysis revealed that age (odds ratio, 0.826; 95% confidence interval, 0.742-0.920) and the short-form Falls Efficacy Scale International score (odds ratio, 0.811; 95% confidence interval, 0.680-0.966) were significantly associated with the single-step threshold, such that older age and greater fear of falling each independently predicted that failure to recover balance with a single step would occur at a lower percentage of body weight. CONCLUSIONS: Greater fear of falling was associated with reduced ability to recover from lateral balance loss in addition to aging. Future studies should explore whether evidence-based interventions to reduce fear of falling combined with perturbation training might lead to improved ability to recover from balance loss.

Association between Productive Roles and Frailty Factors among Community-Dwelling Older Adults: A Cross-Sectional Analysis.

The employment rate of older people in Japan is expected to increase in the future owing to the increase in the retirement age. Preventing frailty is imperative to maintaining productive roles of older adults. Therefore, this study aimed to examine the association between productive roles and frailty factors among community-dwelling older adults. A total of 135 older adults, enrolled in 2017, participated in the study. Productive roles and domains related to frailty were measured. We measured usual gait speed and grip strength for the physical domain; Mini-Mental State Examination (MMSE) and Geriatric Depression Scale (GDS-15) scores for the cognitive and mental domains; and social role and group activity for the social domain. Multivariate-adjusted logistic regression models revealed that having productive roles was associated with faster usual gait speed (odds ratios [OR] = 1.05; 95% confidence interval [CI], 1.01-1.08; p = 0.005) and lower GDS-15 score (OR = 0.79; 95% CI, 0.64-0.97; p = 0.023). These results suggest that health promotion to maintain gait speed and prevent depressive symptoms may contribute to maintaining productivity in community-dwelling older adults.

Spatiotemporal Characteristics of Lateral Reactive Stepping in Individuals with Chronic Stroke.

We compared the spatiotemporal characteristics of lateral perturbation-induced reactive stepping in stroke subjects with those of age-matched controls. We subjected 12 stroke subjects and 17 healthy elderly controls to lateral stepping. We analyzed first-step spatiotemporal parameters during stepping and recorded the selected reactive step types at the stepping threshold. Stroke subjects showed a lower stepping threshold and more frequently used medial steps than controls. Stroke subjects also had a longer delay prior to foot-off in lateral steps when perturbed toward the nonparetic side, and in medial steps when perturbed toward both sides than controls. Thus, the time deficits in reactive stepping in individuals with stroke may be attributed to stroke-related sensorimotor impairments, indicating their limitations in balance control.

Development of the Relationships Among Dynamic Balance Control, Inter-limb Coordination, and Torso Coordination During Gait in Children Aged 3-10 Years.

Knowledge about the developmental process of dynamic balance control comprised of upper arms and upper legs coordination and trunk and pelvis twist coordination is important to advance effective balance assessment for abnormal development. However, the mechanisms of these coordination and stability control during gait in childhood are unknown.This study examined the development of dynamic postural stability, upper arm and upper leg coordination, and trunk and pelvic twist coordination during gait, and investigated the potential mechanisms integrating the central nervous system with inter-limb coordination and trunk and pelvic twist coordination to control extrapolated center of the body mass (XCOM). This study included 77 healthy children aged 3-10 years and 15 young adults. The child cohort was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10 years. Participants walked barefoot at a self-selected walking speed along an 8 m walkway. A three-dimensional motion capture system was used for calculating the XCOM, the spatial margin of stability (MoS), and phase coupling movements of the upper arms, upper legs, trunk, and pelvic segments. MoS in the mediolateral axis was significantly higher in the young adults than in all children groups. Contralateral coordination (ipsilateral upper arm and contralateral upper leg combination) gradually changed to an in-phase pattern with increasing age until age 9 years. Significant correlations of XCOMML with contralateral coordination and with trunk and pelvic twist coordination (trunk/pelvis coordination) were found. Significant correlations between contralateral coordination and trunk/pelvis coordination were observed only in the 5-6 years and at 7-8 years groups.Dynamic postural stability during gait was not fully mature at age 10. XCOM control is associated with the development of contralateral coordination and trunk and pelvic twist coordination. The closer to in-phase pattern of contralateral upper limb coordination improved the XCOM fluctuations. Conversely, the out-of-phase pattern (about 90 degrees) of the trunk/pelvis coordination increased theXCOM fluctuation. Additionally, a different control strategy was used among children 3-8 years of age and individuals over 9 years of age, which suggests that 3-4-year-old children showed a disorderly coordination strategy between limb swing and torso movement, and in children 5-8 years of age, limb swing depended on trunk/pelvis coordination.

Effects of cane use on walking parameters and lower limb muscle activity in adults with spastic cerebral palsy: a cross-sectional study.

[Purpose] Adults with cerebral palsy often use a cane as a walking aid because of their decreased gait ability. However, it is unclear whether this affects lower limb muscle activity during walking. The purpose of this study was to clarify the influence of using a cane during walking on the spatio-temporal parameters of walking, lower limb muscle activity, and lower limb muscle coactivation in adults with spastic cerebral palsy. [Participants and Methods] Eleven participants with cerebral palsy were included. The spatio-temporal parameters of walking, lower limb muscle activity, and coactivation of lower limb muscle were measured during a 10 m trial with no cane, one cane, and two canes. [Results] Walking speed was lower and the stride time longer when using two canes than when using no cane. All muscle activities significantly reduced when using two canes. No significant difference was observed between using no cane and one cane, except for walking speed. In addition, there was no significant difference in coactivation between the conditions. [Conclusion] This study revealed that when two canes were used, the walking speed was reduced, and lower limb muscle activity was reduced, reducing the burden. In contrast, the movement pattern was not suggested to have changed.

Development of temporal and spatial characteristics of anticipatory postural adjustments during gait initiation in children aged 3-10 years.

This study aimed to analyze the development of direction specificities of temporal and spatial control and the coordination pattern of anticipatory postural adjustment (APA) along the anteroposterior (AP) and mediolateral (ML) directions during gait initiation (GI) in children aged 3-10 years. This study included 72 healthy children aged 3-10 years and 14 young adults. The child population was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10 years. The GI task included GI using the dominant limb. The peak center of feet pressure (COP) shifts during APAs (APApeak), initiation time of COP shifts (APAonset), and the COP vectors in the horizontal plane were calculated to evaluate the direction specificity of spatial, temporal, and coordination control, respectively. A difference in direction specificity development was found for the APApeak. The APApeak in the mediolateral axis, but not in the anteroposterior axis, was significantly higher in the 7-8 years age group than in other groups. Although APAonset was not found for direction specificity, a significant difference between the adult and children groups (5-6 years, 7-8 years, and 9-10 years) was observed in the direction of the COP vector. In conclusion, the developmental process of the spatial, temporal, and coordination control of APAs during GI varied with age. Furthermore, the spatial control and coordination pattern of APAs was found to be direction specific. All components of APAs, namely temporal and spatial control, coordination pattern, and direction specificities, should be analyzed to capture the developmental process of anticipatory postural control.

Resveratrol improves motor function in patients with muscular dystrophies: an open-label, single-arm, phase IIa study.

Muscular dystrophies (MDs) are inherited disorders characterized by progressive muscle weakness. Previously, we have shown that resveratrol (3,5,4'-trihydroxy-trans-stilbene), an antioxidant and an activator of the protein deacetylase SIRT1, decreases muscular and cardiac oxidative damage and improves pathophysiological conditions in animal MD models. To determine whether resveratrol provides therapeutic benefits to patients with MDs, an open-label, single-arm, phase IIa trial of resveratrol was conducted in 11 patients with Duchenne, Becker or Fukuyama MD. The daily dose of resveratrol was 500 mg/day, which was increased every 8 weeks to 1000 and then 1500 mg/day. Primary outcomes were motor function, evaluated by a motor function measure (MFM) scale, muscular strength, monitored with quantitative muscle testing (QMT), and serum creatine kinase (CK) levels. Adverse effects and tolerability were evaluated as secondary outcomes. Despite the advanced medical conditions of the patients, the mean MFM scores increased significantly from 34.6 to 38.4 after 24 weeks of medication. A twofold increase was found in the mean QMT scores of scapula elevation and shoulder abduction. Mean CK levels decreased considerably by 34%. Diarrhoea and abdominal pain was noted in six and three patients, respectively. Resveratrol may provide some benefit to MD patients.

Utility of Dynamic Balance Measurements in Discriminating Community Ambulation Levels Among Individuals with Stroke: A Cross-sectional Study.

OBJECTIVE: To examine the association between dynamic balance measurements and community ambulation levels among individuals with chronic stroke. METHODS: This cross-sectional study was performed in 2-day care facilities for older adults located in urban areas. Forty-seven community-dwelling poststroke adults who could walk independently were participated. Community ambulation performance was assessed using the Functional Ambulation Classification of the Hospital at Sagunto (FACHS). Dynamic balance and mobility were measured with the Mini-Balance Evaluation Systems Test (Mini-BESTest), the Timed Up and Go (TUG) test, and 10 m maximum walking speed. RESULTS: Participants were classified into 3 groups according to FACHS scores: household (n = 15), neighborhood (n = 19), and community walkers (n = 13). Neighborhood and community walkers scored significantly higher on the Mini-BESTest and had a shorter TUG test time than household walkers. Community walkers had a significantly faster walking speed than household walkers, whereas neighborhood walkers did not have a faster walking speed than household walkers. Ordinal logistic regression analyses revealed the Mini-BESTest score (odds ratio [OR] 1.24; 95% confidence interval [CI]: 1.07-1.44) and the TUG test time (OR .91; 95% CI: .85-.98) were significantly associated with ambulation levels after adjusting for confounders. CONCLUSIONS: Dynamic balance measurement tools may have better responsiveness in detecting community ambulation levels among individuals with chronic stroke than walking speed.

A Preliminary Evaluation of Energy Efficiency for Children with Cerebral Palsy for Driving A Manual Wheelchair and Walking: Use of the Total Heart Beat Index.

Aims: This study aims to compare the total heart beat index (THBI) in evaluating energy efficiency between using a manual wheelchair and walking for children with cerebral palsy (CP). Methods: The energy efficiency was measured in 21 participants with CP (mean age, 13.6 ± 3.4 years) who walk or drive a manual wheelchair using a square course. THBI was calculated as total number of heart beats during the exercise period/total distance traveled. Results: Significant differences in the THBI were observed between Gross Motor Function Classification System (GMFCS) levels III and IV (p = .049, effect size = 1.60). No significant differences in THBI were observed between GMFCS levels II and III or between GMFCS levels II and IV (p > .05). Conclusions: The energy efficiency of children with CP who use a manual wheelchair in this study was equal to or better than that for walking.

Life-Space Mobility and Relevant Factors in Community-dwelling Individuals with Stroke in Japan: A Cross-sectional Study.

OBJECTIVE: Individuals with stroke frequently experience mobility deficits and limited community reintegration. This study aimed to investigate life-space mobility and relevant factors in community-living individuals with stroke. METHODS: This was a cross-sectional study of 46 community-dwelling individuals with chronic stroke in Japan (mean age 72.7 ± 7.4 years; mean time post-stroke 63.6 ± 43.3 months; 26 men/20 women). We measured life-space mobility using a Japanese translation of the Life-Space Assessment. The following factors that might affect life-space mobility were assessed: the ability to perform activities of daily living, physical performance, fear of falling, and cognitive function. RESULTS: A total of 41 participants (89.1%) had restricted life-space mobility (Life-Space Assessment score <60 points). A multiple linear regression analysis showed that limitations in activities of daily living, walking speed, and Falls Efficacy Scale-International scores were independently related to Life-Space Assessment scores. This model explained 51.3% of the variance in Life-Space Assessment scores. CONCLUSIONS: Most individuals with stroke had restricted life-space mobility. Life-space mobility was associated with the ability to perform activities of daily living, walking speed, and fear of falling. These findings could contribute to the development of rehabilitation interventions for regaining life-space mobility in individuals with stroke.

Development of postural control during single-leg standing in children aged 3-10 years.

BACKGROUND: The ability to control the center of mass (COM) during single-leg standing (SLS) is imperative for individuals to walk independently. However, detailed biomechanical features of postural control during SLS performed by children remain to be comprehensively investigated. RESEARCH QUESTION: We aimed to investigate the development of postural control during SLS in children aged 3-10 years. METHODS: Forty-eight healthy children (26 boys and 22 girls) aged 3-10 years and 11 young adults participated in this experiment. The child population was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10 years. The SLS task included standing on a single leg as long and as steady as possible for up to 30 s. A three-dimensional motion capture system and two force plates were used for calculating the COM and center of pressure (COP). The task was divided into three phases (accelerated, decelerated, and steady) on the basis of the relationship between COM and COP. RESULTS: COP-COM distances in the 5-6 years' and 7-8 years' groups were significantly increased during the acceleration phase when compared with those in the adult group. Furthermore, COP-COM distances during the decelerated phase were significantly higher in all children's groups compared with those in the adult group. Lastly, COP-COM distance during the steady phase was significantly higher in the 3-4 year age group than in the 9-10 year age and adults groups. SIGNIFICANCE: These results suggest that postural control during the acceleration and steady phases mature by 9 years. Conversely, children ∼10 years did not attain adult-like levels of postural control during the decelerated phase. The developmental process for postural control at each phase possibly plays a significant role in the basic biomechanics of movement and does not display a monotonic pattern.

Spontaneous movements of preterm infants is associated with outcome of gross motor development.

AIMS: We conducted a longitudinal cohort study to analyze the relationship between outcome of gross motor development in preterm infants and factors that might affect their development. METHODS: Preterm infants with a birth weight of <1500 g were recruited. We measured spontaneous antigravity limbs movements by 3D motion capture system at 3 months corrected age. Gross motor developmental outcomes at 6 and 12 months corrected age were evaluated using the Alberta Infant Motor Scale (AIMS). Statistical analysis was carried out by canonical correlation analysis. RESULTS: Eighteen preterm infants were included. In the 6 months corrected age analysis, spontaneous movement had a major effect on Prone and Sitting at 6 months corrected age of AIMS. In the 12 months corrected age analysis, spontaneous movement had a major effect on Sitting and Standing at 12 months corrected age of AIMS. CONCLUSIONS: In preterm infants, better antigravity spontaneous movements at 3 months corrected age were significantly correlated with better gross motor development at 6 or 12 months corrected age.

Family-centered care for preterm infants: Parent and physical therapist perceptions.

BACKGROUND: The aim of this study was to compare perceptions between physical therapists and parents about family-centered care for preterm infants. METHODS: Translated versions of the Measure of Processes of Care-20 and Measures of Processes of Care for Service Providers were used to evaluate the family-centered care for preterm infants. RESULTS: A total of 42 parents of 44 preterm infants and nine physical therapists completed questionnaires. Parent perceptions of the family-centered care were generally positive. The highest rating was in the domain Enable and Partnership. Physical therapists gave lower scores in all information domains. There were some gaps between parent and physical therapist perceptions of information domains. CONCLUSIONS: Strengths and weaknesses in family-centered care for preterm infants have been identified. Parents viewed the role of physical therapists in family-centered care for preterm infants as positive.

Reliability and validity of standing balance assessment index using a hand-held dynamometer in stroke patients.

[Purpose] This study aimed to determine the reliability and validity of our standing balance assessment index using a hand-held dynamometer (the hand-held dynamometer assessment index) in stroke patients. [Subjects and Methods] The participants were 60 stroke patients with impaired standing balance. Intrarater and interrater reliabilities were evaluated employing the intraclass correlation coefficient. Criterion-related validity was evaluated by Spearman's rank correlation coefficient between the HHD assessment index and the functional balance scale. [Results] The intraclass correlation coefficient values obtained ranged from 0.91 to 0.98, and the correlation coefficient with the FBS was 0.83. [Conclusion] Our findings confirmed the reliability and validity of the hand-held dynamometer assessment index in stroke patients.

Characteristics of antigravity spontaneous movements in preterm infants up to 3 months of corrected age.

AIMS: We investigated whether spontaneous antigravity limbs movements in very low birth weight preterm infants were insufficient compared to those in term infants. The relationship between the quality of general movements (GMs) and antigravity limbs movements was also examined. METHODS: Preterm infants with very low birth weight without central nervous system disorders nor severe respiration disorders, and healthy term infants were recruited. The infants were set in a supine position. The distance between both hands and between both feet, and the height of both hands and feet from the floor were recorded at 1-3 corrected months for preterm infants, and at 1-3 months for term infants by a 3D motion capture system. The measurements were adjusted for body proportions. GMs in preterm and term infants were assessed similarly. RESULTS: Thirteen preterm and 15 term infants completed the study. In preterm infants, the distance between both hands and between both feet were longer, and the height of both hands and feet were lower than those in term infants in all measurements. In term infants, the height of both hands and feet increased as they developed, but no change was observed in preterm infants. In preterm infants with abnormal GMs, the distance between both hands was longer, and the height of both hands and feet was lower than that in those with normal GMs. There were no such differences between preterm infants with normal GMs and term infants with normal GMs. CONCLUSION: Antigravity limbs movements in preterm infants within the first 3 month of corrected age were insufficient compared with those in term infants. Furthermore, no improvement with development was observed in preterm infants. In addition, preterm infants with abnormal GMs showed worse antigravity limbs movements than preterm and term infants with normal GMs. The preterm infants with normal GMs could behave similar to the full term infants.

Human fetal anatomy of the posterior semimembranosus complex at the knee with special reference to the gastrocnemio-semimembranosus bursa.

There is little information on the fetal anatomy of the posterior semimembranosus tendinous complex and its associated bursa. We examined histological sections (transverse or sagittal) of the right or left knee in 13 mid-term human fetuses (12-25 weeks of gestation). The medial head of the gastrocnemius provided an aponeurosis facing or attached to the muscles of the pes anserinus by 12 weeks of gestation. The peritendinous tissue of the semimembranosus provided a bursa continuous with a laterally extending plate-like tissue by 15 weeks, but sometimes the typical bursa was absent. The aponeurosis of the medial head consistently accompanied a bursa-like space (false bursa) surrounded by heterogenous structures including the popliteus and a wall of the semimembranosus bursa. Sagittal sections displayed notches on the medial head surface that received the semimembranosus and semitendinosus overriding the medial head of the gastrocnemius. In contrast to a real bursa originating from the peritendinous tissue of the semimembranosus, a false bursa without a homogeneous wall consistently develops at the origin of the medial head of the gastrocnemius. Due to mechanical stress from the tendons, the false bursa is likely to develop into a structure similar to a real bursa with a synovial lining even if the real bursa is absent in the fetus. We hypothesize that the adult gastrocnemio-semimembranosus bursa, largely or partly, originates from the fetal false bursa. Absolute resection of the false bursa is difficult because it is a mere gap between normal tissues.