[Reconstruction of the breast after mastectomy using an island flap from the latissimus dorsi muscle without endoprosthesis].
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Lumbar strengthening in chronic low back pain patients. Physiologic and psychological benefits.
The effects of exercise for isolated lumbar extensor muscles were examined in 54 chronic low-back pain patients. Subjects were randomly assigned to a 10-week exercise program (N = 31) or a wait-list control group (N = 23). Results indicated a significant increase in isometric lumbar extension strength for the treatment group and a significant reduction in reported pain compared with the control group (P 0.05). Treated subjects reported less physical and psychosocial dysfunction whereas the control group increased in pain, and physical and psychosocial dysfunction. There were no concomitant changes in reported daily activity levels. These results show that lumbar extension exercise is beneficial for strengthening the lumbar extensors and results in decreased pain and improved perceptions of physical and psychosocial functioning in chronic back pain patients. However, these improvements were not related to changes in activities or psychological distress.
Adult↗
Nontropical pyomyositis in adults.
Pyomyositis (PMS) is a primary infection of striated muscle. Recent scanty reports suggest that non-tropical PMS may differ from classical tropical PMS. To address this question, 12 cases of nontropical PMS seen at two hospitals between 1976 and 1992 were reviewed and an English-literature search of similar cases was conducted. Both the series and reported cases are pooled together and herein reported. The age distribution of the 97 patients showed 30-50 and 60-70-year peaks, with a 3:1 (male-female) ratio. Fever, high erythrocyte sedimentation rate, and muscle stiffness or inflammation were present in more than 75% of patients. Muscles of the thigh (54%), back (13%), buttock (11%), arm (9%), or chest wall (4%) were involved. Staphylococci (61%), gram-negative bacilli (16%), streptococci (12%), and fungi (2%) were isolated from muscle specimens. Human immunodeficiency virus infection, diabetes mellitus, hemopoietic disorders, and other conditions with defective neutrophil function were present in 64 patients (66%). Drainage of pus and antibiotic therapy were the standard treatments. The mortality rate reached 10%. Analysis of patients classified by the comorbid condition showed differences in age, causative microorganisms, clinical features, and death rate. It is concluded that several clinical presentations of nontropical PMS are at variance with that of tropical PMS.
Adult↗
EMG to torque relationship in rectus abdominis muscle. Results with repeated testing.
Rectus abdominis muscles of young healthy female volunteers were studied to determine both the maximum strength in isometric flexion and the relation between the surface electromyogram (RMS EMG) and torque. Both the upper and lower portions of the abdominal muscle were studied during graded increase and decrease of torque. Repeated testing was performed over 6 weeks. The form of the relation between torque and EMG was better described by a quadratic than by a linear regression relationship, but with considerable variability about the best-fit line. The torque-increasing and torque-decreasing parts of each test were different and were analyzed separately. After 6 weeks of repeated testing, maximum voluntary isometric flexion torque increased 16.8% (P less than 0.01). There was a decrease in the ratio of electromyographic activity to torque production, which was statistically significant in the torque-increasing recordings. These changes in maximum torque and in the EMG-torque relation were attributed to learning through a test-retest effect, rather than to a true change in muscle characteristics. These findings, which show changes in normal subjects undergoing repeated testing, do not support the reliability of isometric strength measurements, or measurements based on RMS EMG recordings, for quantifying abdominal muscle function in patients with back pain, or those undergoing strengthening exercises.
Abdominal Muscles↗
Relationships between peak force, action potential duration and stimulus interval in rabbit myocardium.
Isometric force and membrane action potential were recorded simultaneously in rabbit papillary muscles (36.5 degrees--37.5 degrees C). One to three test stimuli were given at various intervals (0.20--10.0 s) after a series of control contractions at constant stimulation intervals (1.0--1.5 s). Optimum peak force always occurred when the preceding test interval was 0.80 s. When this interval was greater than 0.80 s, time to peak force was a linear function of the action potential duration. Furthermore, under these conditions the action potential duration (AP1) and peak force (F1) of the test contraction could be used to predict peak force (F2) of the subsequent contraction elicited after a fixed interval (0.80--1.50 s) according to the equation (regression plane): F2 = BAPAP1 + BFF1 + A. Constants BAP and BF are interpreted to provide information about calcium influx during the action potential and of the recirculation of calcium between contractions, respectively. F2 deviated towards higher values than predicted from the equation when the preceding test contraction was triggered to occur at an interval less than 0.80 s. This may be due to an intensified calcium transport into the cell during the action potential after these short intervals. The action potential duration was inversely related to both the inotropic state of the muscle (representing a feed-back mechanism) and the preceding stimulation interval.
Action Potentials↗
The effect of pre-season dance training on physical indices and back pain in elite cross-country skiers: a prospective controlled intervention study.
OBJECTIVE: To evaluate the effect of pre-season dance training on back pain, joint mobility, and muscle flexibility, and on speed and agility in elite cross-country skiers. METHODS: 26 skiers participated (mean (SD) age, 19 (3.9) years). An intervention group (n = 16) had 12 weeks of dance training; a control group (n = 10) did not dance; otherwise both groups followed a similar pre-season physical training programme. Joint mobility and muscle flexibility of the spine, hip, and ankle were measured. Two sports related functional tests (slalom and hurdle) were also done. All measurements/tests were carried out before and after the dancing period. RESULTS: Four (of six) subjects from the intervention group who initially complained of ski related back pain did not report back pain after the dance training; the three subjects with back pain from the control group were unchanged. At study onset the intervention group had a slightly impaired range of motion in the spine compared with the control group. After dance training, there was a better relation between kyphosis of the thoracic spine and lordosis of the lumbar spine, and a 7.1 degrees increase in hip flexion with the knee extended (p = 0.02). In the control group hip extension decreased by 0.08 m on average (p = 0.01). No positive effects of dance training on sports related functional tests were observed. CONCLUSIONS: Preseason dance training improved the range of hip motion and joint mobility and the flexibility of the spine. These improvements might explain the reduction in ski related back pain in the intervention group.
Adolescent↗
Prediction of joint moments using a neural network model of muscle activations from EMG signals.
Because the relationship between electromyographic (EMG) signals and muscle activations remains unpredictable, a new way to determine muscle activations from EMG signals by using a neural network is proposed and realized. Using a neural network to predict the muscle activations from EMG signals avoids establishing a complex mathematical model to express the muscle activation dynamics. The feed-forward neural network model of muscle activations applied here is composed of four layers and uses an adjusted back-propagation training algorithm. In this study, the basic back-propagation algorithm was not applicable, because muscle activation could not be measured, and hence the error between predicted activation and the real activation was not available. Thus, an adjusted back-propagation algorithm was developed. Joint torque at the elbow was calculated from the EMG signals of ten flexor and extensor muscles, using the neural network result of estimated activation of the muscles. Once muscle activations were obtained, Hill-type models were used to estimate muscle force. A musculoskeletal geometry model was then used to obtain moment arms, from which joint moments were determined and compared with measured values. The results show that this neural network model can be used to represent the relationship between EMG signals and joint moments well.
Action Potentials↗
Multiple pains and psychosocial functioning/psychologic distress in TMD patients.
PURPOSE: This study assessed multiple pain conditions and their association with psychosocial functioning, psychologic distress, and somatization in patients with temporomandibular disorders (TMD) based on RDC/TMD Axis II findings. Nonspecific pain items examined included headaches, heart/chest pain, lower back pain, nausea/abdominal pain, and muscle pain. MATERIALS AND METHODS: In this study, 202 TMD patients (58 men and 144 women) referred to two TMD clinics participated. The mean age of the predominantly Chinese patient population (82%) was 32.6 years (range 13 to 65). The RDC/TMD history questionnaire was input directly into computers by patients. Graded chronic pain and SCL-90 scales were generated online and automatically archived for statistical analysis. Data were subjected to Spearman's rank-order correlation and Kruskal-Wallis and Mann-Whitney tests at a significance level of .05. RESULTS: Of the patients, 43% were moderately to extremely distressed by headaches. The percentage of patients who were distressed by heart/chest pain (7%), lower back pain (26%), nausea/abdominal pain (17%) and soreness of muscles (22%) was lower. Of the TMD patients, 16% experienced more than three pain items. Significant and positive correlations were observed between number of pain items experienced and graded chronic pain severity, depression, and somatization. Correlation coefficients ranged from .27 to .65 for graded chronic pain scales and somatization (without pain items) scores, respectively. CONCLUSION: Results suggest that the number of nonspecific pain conditions reported may be a predictor of psychosocial dysfunction, depression, and somatization.
Adolescent↗
Post-contraction errors in human force production are reduced by muscle stretch.
1. Based on findings from a previous study of plantar-flexor muscles, the effect of a conditioning 25, 50 or 100% maximum voluntary contraction (m.v.c.) of elbow flexor muscles on the accuracy of reproducing a learned criterion muscle force (2% m.v.c.) was investigated. 2. Each conditioning contraction induced a significant error in reproducing the criterion muscle force under conditions of no visual feed-back of force. As with plantar-flexor muscles, the error was consistently in the direction of a positive bias. The magnitude of the error co-varied with the magnitude of the previous contraction and, in all cases, decayed toward criterion force values over a 35 s period. 3. A brief muscle stretch, induced before subjects attempted the criterion force, reduced the size of the error but did not completely eliminate the bias. 4. The findings provide indirect evidence of post-contraction potentiation of stretch reflex pathways. Residual post-contraction errors in force production after muscle stretch may be attributed to other central or peripheral neural factors such as, for example, potentiating effects of prior activation on submaximal tension production in skeletal muscle.
Adult↗
[Body posture and dorsal muscles in phylogenesis].
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Animals↗
Reticulospinal connections with limb and axial motoneurons.
Responses of motoneurons supplying muscles of the forelimbs, hindlimbs, back, and neck to stimulation of the medial pontomedullary reticular formation were studied with intracellular recording in cerebellectomized cats under chloralose anesthesia. Stimulation of the midline or of a reticular region consisting of nucleus reticularis (n.r.) pontis caudalis and the dorsorostral part of n.r. gigantocellularis produced monosynaptic excitation of ipsilateral motoneurons supplying axial muscles and flexor and extensor muscles in both proximal and distal parts of the limbs. This widespread excitation appears to have been produced by rapidly conducting medial reticulospinal fibers. Stimulation of a second region consisting of n.r. ventralis and the ventrocaudal part of n.r. gigantocellularis produced monosynaptic excitation of ipsilateral neck and back motoneurons but only longer latency, apparently multisynaptic excitation of limb motoneurons. Collision tests indicated that this monosynaptic excitation did not involve fibers descending along the midline. It therefore appears to have been produced by lateral reticulospinal fibers. Reticular stimulation also produced short latency, monosynaptic inhibition of neck motoneurons, long latency, apparently polysynaptic inhibition of limb motoneurons and intermediate latency inhibition of back motoneurons. The latencies and properties of inhibitory responses of back motoneurons indicated that they were produced either disynaptically by fast fibers or monosynaptically by slower fibers. The data indicate that the medial pontomedullary reticular formation can be divided into a number of different zones each with a distinct pattern of connections with somatic motoneurons. These include the dorsorostrally located medial reticulospinal projection area, from which direct excitation of a wide variety of motoneurons can be evoked, the ventrocaudally located lateral reticulospinal projection area from which direct excitation of neck and back and direct inhibition of neck motoneurons can be evoked and the dorsal strip of n.r. gigantocellularis which has direct excitatory and inhibitory actions only on neck motoneurons.
Animals↗
Emery-Dreifuss syndrome.
A young adult male is described with muscular dystrophy of probable X-linked recessive inheritance. An onset of muscle weakness in late adolescence was preceded by contractures of the neck and elbows dating back to childhood. The distribution of muscle weakness was proximal in the upper limbs and both proximal and distal in the lower. The mixed pattern of muscle involvement in the legs favours the view that cases of Emery-Dreifuss muscular dystrophy with proximal weakness in both the upper and lower limbs and X-linked scapuloperoneal muscular dystrophy represent the same disorder. A muscle biopsy in the present case showed unique appearances.
Adult↗
Harmaline induces different motor effects on facial vs. skeletal-motor systems in alert cats.
Harmaline's effects on reflex and classically conditioned eyelid responses and on tremor picked up by a coil attached to the back were measured in alert cats. Harmaline at a dose of 10 mg/kg produced skeletal muscle tremogenic effects that lasted 4h. Back movements presented a tremor-like displacement with a frequency peak at 10 Hz, but lid responses oscillated as in controls, at 20 Hz during both reflex and conditioned eyelid movements, with no increase in oscillation amplitude or frequency. The learning curves of harmaline-injected animals remained as in controls, but eyelid conditioned responses showed longer latencies, and smaller amplitude and peak velocity. Reflex and already-learned eyelid responses were not modified by harmaline. These results imply that neuronal control systems for skeletal-motor and facial responses are differentially affected by harmaline.
Journal Article↗
The rectogenital septum: morphology, function, and clinical relevance.
PURPOSE: The rectogenital septum (known in clinical literature as Denonvilliers' fascia) forms an incomplete partition between the rectum and the urogenital organs in both men and women. It is composed of collagenous and elastic fibers and smooth muscle cells intermingled with nerve fibers emerging from the autonomic inferior hypogastric plexus. The aim of this study was to investigate the fetal development of the rectogenital septum, and the origin and innervation of the longitudinal smooth muscle cells within the septum, as well as to consider possible effects on function of operations that compromise the integrity of these structures. METHODS: Macroscopic dissections on embalmed human pelves and plastination histology of 40 fetal and newborn pelvic specimens were performed. By means of conventional and immunohistochemical staining methods using monoclonal and polyclonal antibodies for tissue analysis and neuronal labeling, the motor and sensory innervation of the longitudinal muscle bundles within the septum was defined. RESULTS: The rectogenital septum is formed by a local condensation of mesenchymal connective tissue in the early fetal period. The longitudinal muscle bundles could be traced back to the longitudinal layer of the rectal wall, and, using the septum as a guiding structure, it was possible to identify autonomic nerve fibers and ganglion cells innervating the muscle cells and crossing the midline without detectable gender differences. CONCLUSIONS: Because of a coinnervation of the rectal muscle layers and the adjacent longitudinal muscle fibers of the septum, a functional correlation between the two structures during defecation is postulated. On the basis of these findings, a safer dissection of the anterior rectal wall during rectal resection is postulated, thus limiting functional disturbance and preventing neural damage.
Adult↗
Low back pain in young athletes. A practical approach.
Lumbar spine pain accounts for 5 to 8% of athletic injuries. Although back pain is not the most common injury, it is one of the most challenging for the sports physician to diagnose and treat. Factors predisposing the young athlete to back injury include the growth spurt, abrupt increases in training intensity or frequency, improper technique, unsuitable sports equipment, and leg-length inequality. Poor strength of the back extensor and abdominal musculature, and inflexibility of the lumbar spine, hamstrings and hip flexor muscles may contribute to chronic low back pain. Excessive lifting and twisting may produce sprains and strains, the most common cause of low back pain in adolescents. Blows to the spine may create contusions or fractures. Fractures in adolescents from severe trauma include compression fracture, comminuted fracture, fracture of the growth plate at the vertebral end plate, lumbar transverse process fracture, and a fracture of the spinous process. Athletes who participate in sports involving repeated and forceful hyperextension of the spine may suffer from lumbar facet syndrome, spondylolysis, or spondylolisthesis. The large sacroiliac joint is also prone to irritation. The signs and symptoms of disc herniation in adolescents may be more subtle than in adults. Disorders simulating athletic injury include tumours and inflammatory connective tissue disease. Often, however, a specific diagnosis cannot be made in the young athlete with a low back injury due to the lack of pain localisation and the anatomic complexity of the lumbar spine. A thorough history and physical examination are usually more productive in determining a diagnosis and guiding treatment than imaging techniques. Diagnostic tests may be considered, though, for the adolescent athlete whose back pain is severe, was caused by acute trauma, or fails to improve with conservative therapy after several weeks. Radiographs, bone scanning, computed tomography, and magnetic resonance imaging may help identify, or exclude serious pathology. Fortunately, the majority of cases of low back pain in adolescents respond to conservative therapy. Immediate treatment of an acute injury, such as a sprain or strain, includes cryotherapy, electrogalvanic stimulation, anti-inflammatory medications and gentle exercises. Prolonged bed rest should be avoided since atrophy may occur rapidly. Strong analgesics are also usually contraindicated, except for sleep, since they mask pain and may allow overvigorous activity. Early strengthening exercises include the Williams flexion exercises and/or McKenzie extension exercises. Both exercise motions may often be prescribed. Athletes with an acute disc herniation, however, should only perform extension exercises initially. Athletes with spondylolysis, spondylolisthesis and facet joint irritation should initially be limited to flexion exercises.(ABSTRACT TRUNCATED AT 400 WORDS)
Adolescent↗
An in vivo model for evaluating wound repair and regeneration microenvironments.
BACKGROUND: Factors differentially regulating regeneration and repair as contrasting resolutions to injury are unknown. We adapted a common wound healing model to further characterize mammalian wound repair and regeneration microenvironments. METHODS: Polyvinyl alcohol sponges, sponges containing minced muscle, or blocks of minced muscle were implanted onto the backs of Fischer rats. Vascularization was assessed by infusion with india ink and progress of regeneration was evaluated histologically. RESULTS: Regeneration occurring within sponges was histologically similar to that of free muscle blocks; but, was initiated more slowly. Vascularization of minced muscle implanted in sponges was delayed slightly compared to implanted free muscle blocks. CONCLUSIONS: Regeneration of minced muscle in sponges parallels normal regeneration of free minced muscle. Incorporation into a wound repair model provides access to interstitial fluids conditioned by regenerating muscle and will lead to more detailed comparisons of the content and properties of repair and regeneration microenvironments.
Animals↗
Diagonal trunk muscle exercises in peripartum pelvic pain: a randomized clinical trial.
BACKGROUND AND PURPOSE: Exercises for low back and pelvic pain are supposed to increase muscle force to reduce symptoms, but they could exacerbate symptoms by loading of the spinal and pelvic structures. The purpose of this study was to investigate the value of graded exercises of the diagonal trunk muscle systems. SUBJECTS: The subjects were 44 women with persistent pelvic pain after pregnancy (mean age=31.7 years, SD=3.2, range=23.6-37.5; mean period postpartum=4.1 months, SD=2.2, range=1.7-5.6). METHODS: Subjects were randomly assigned to 1 of 3 groups: (1) a group that performed exercises to increase the force of the diagonal trunk muscle systems, (2) a group that received training of the longitudinal trunk muscle systems, and (3) a group that was instructed to refrain from exercises. Pain, fatigue, perceived general health, and mobility of the pelvic joints as measured with radiographs were the outcome measures. RESULTS: After 8 weeks, no differences were found among the 3 groups. CONCLUSION AND DISCUSSION: In treating patients with persistent pelvic pain, training of the diagonal trunk muscle systems, without individual coaching, has no additional value above instructions and use of a pelvic belt without exercises. Whether the treatment is ineffective or whether exacerbation of symptoms due to loading of the spinal and pelvic structures obscures any potential benefit of increased muscle force cannot be determined from the study design.
Abdominal Muscles↗
Spectral parameters of trunk muscles during fatiguing isometric axial rotation in neutral posture.
Axial rotation of the trunk is commonly associated with back injury and pain. However, the behaviour of trunk muscles in axial rotation is poorly understood. The objective of this study was to measure spectral parameters from the EMG of erector spinae at T10 and L3 levels, latissimus dorsi, external and internal oblique, rectus abdominis and pectoralis major muscles bilaterally in a standardized repeatable axial rotation at 60% MVC to fatigue. Twelve young and healthy subjects were recruited after screening for musculoskeletal disorders. Surface electrodes were applied to the named seven trunk muscles bilaterally. Subjects were seated in the device called Axial Rotation Tester and stabilized such that they could rotate only their thoracolumbar spine. Other motions were prevented. Subjects held 60% of their MVC for a period of 2 min. Samples (2.1 s) were obtained at every 10 s interval at a sampling frequency of 1 KHz. Samples were subjected to FFT analysis. The total power and the median frequencies were analyzed. The median frequency for different muscles were different (p < 0.001). The slopes of decline of the median frequencies of the agonists were different for different muscles (p < 0.001). This differential fatiguing rate could conceivably create a force imbalance potentiating back injury.
Abdominal Muscles↗