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PubMed1992

Electromyographic detection of paraspinal muscle metastasis. Correlation with magnetic resonance imaging.

Electromyographic (EMG) examination demonstrating marked segmental compromise of the posterior primary ramus distal to the spinal root with relative sparing of the anterior ramus may be the earliest objective evidence of paraspinal muscle metastasis. Antecedent studies are often initially normal, failing to disclose the underlying cause of back pain. Although paraspinal muscle metastasis has been histopathologically demonstrated at postmortem, attempts to image the suspected malignancy with computed tomography have been unsuccessful because the tumor in muscle remains isodense. This study reports the use of magnetic resonance imaging (MRI) to substantiate the existence of EMG-suspected paraspinal muscle metastasis. An EMG pattern of segmental posterior primary ramus denervation is not pathognomonic of metastasis. A confirmatory MRI, however, does permit earlier treatment with palliative radiation therapy.

Adenocarcinoma↗
PubMed1995

Early stages of chick somite development.

We report on the formation and early differentiation of the somites in the avian embryo. The somites are derived from the avian embryo. The somites are derived from the mesoderm which, in the body (excluding the head), is subdivided into four compartments: the axial, paraxial, intermediate and lateral plate mesoderm. Somites develop from the paraxial mesoderm and constitute the segmental pattern of the body. They are formed in pairs by epithelialization, first at the cranial end of the paraxial mesoderm, proceeding caudally, while new mesenchyme cells enter the paraxial mesoderm as a consequence of gastrulation. After their formation, which depends upon cell-cell and cell-matrix interactions, the somites impose segmental pattern upon peripheral nerves and vascular primordia. The newly formed somite consists of an epithelial ball of columnar cells enveloping mesenchymal cells within a central cavity, the somitocoel. Each somite is surrounded by extracellular matrix material connecting the somite with adjacent structures. The competence to form skeletal muscle is a unique property of the somites and becomes realized during compartmentalization, under control of signals emanating from surrounding tissues. Compartmentalization is accompanied by altered patterns of expression of Pax genes within the somite. These are believed to be involved in the specification of somite cell lineages. Somites are also regionally specified, giving rise to particular skeletal structures at different axial levels. This axial specification appears to be reflected in Hox gene expression. MyoD is first expressed in the dorsomedial quadrant of the still epithelial somite whose cells are not yet definitely committed. During early maturation, the ventral wall of the somite undergoes an epithelio-mesenchymal transition forming the sclerotome. The sclerotome later becomes subdivided into rostral and caudal halves which are separated laterally by von Ebner's fissure. The lateral part of the caudal half of the sclerotome mainly forms the ribs, neural arches and pedicles of vertebrae, whereas within the lateral part of the rostral half the spinal nerve develops. The medially migrating sclerotomal cells form the peri-notochordal sheath, and later give rise to the vertebral bodies and intervertebral discs. The somitocoel cells also contribute to the sclerotome. The dorsal half of the somite remains epithelial and is referred to as the dermomyotome because it gives rise to the dermis of the back and the skeletal musculature. the cells located within the lateral half of the dermomyotome are the precursors of the muscles of the hypaxial domain of the body, whereas those in the medial half are precursors of the epaxial (back) muscles.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2000

Correlation between the MRI changes in the lumbar multifidus muscles and leg pain.

AIM: In the assessment of the lumbar spine by magnetic resonance imaging (MRI), changes in the paraspinal muscles are frequently overlooked. In this study, our objective was to investigate the relationships between lumbar multifidus (MF) muscle atrophy and low back pain (LBP), leg pain and intevertebral disc degeneration. METHODS: A retrospective study of 78 patients (aged 17-72) with LBP presenting with back pain with or without associated leg pain was undertaken. Their MR images were visually analysed for signs of lumbar MF muscle atrophy, disc degeneration and nerve root compression. The clinical history in each case was obtained from their case notes and pain drawing charts. RESULTS: MF muscle atrophy was present in 80% of the patients with LBP. The correlation between MF muscle atrophy and leg pain was found to be significant (P < 0.01). However, the relationships between muscle atrophy and radiculopathy symptoms, nerve root compression, herniated nucleus pulposus and number of degenerated discs were statistically not significant. CONCLUSION: Examination of the paraspinal muscles looking for atrophy of MF muscle should be considered when assessing MR images of lumbar spine. This may explain the referred leg pain in the absence of other MR abnormalities.

Adolescent↗
PubMed2001

Effects of treadmill speed on the mechanics of the back in the trotting saddlehorse.

Speed related changes in trunk mechanics have not yet been investigated, although high-speed training is currently used in the horse. To evaluate the effects of speed on back kinematics and trunk muscles activity, 4 saddle horses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5 to 6 m/s. The 3-dimensional (3-D) trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was simultaneously obtained from the longissimus dorsi (LD) and rectus abdominis (RA) muscles using surface electrodes. Ten consecutive strides were analysed for each horse at each of the 5 velocity steps. Electromyographic and kinematic data were time-standardised to the duration of the stride cycle and compared using an analysis of variance. The back extended during the first part of each diagonal stance phase when the RA was active and the back flexed during the second part of each diagonal stance phase when the LD was active. The onset and end of muscle activity came earlier in the stride cycle and muscle activity intensity increased when speed increased. The amplitude of vertical movement of the trunk and the maximal angles of flexion decreased with increasing speed, whereas the extension angles remained unchanged. This resulted in a decreased range of back flexion-extension. This study confirms that the primary role of trunk muscles is to control the stiffness of the back rather than to induce movements. Understanding the effects of speed on the back of healthy horses is a prerequisite for the prevention and treatment of back pathology.

Animals↗
PubMed2002

Intra-tester reproducibility of pressure biofeedback in measurement of transversus abdominis function.

BACKGROUND AND PURPOSE: Strength, co-ordination and timing of transversus abdominis muscle contraction may be important in stabilizing the low back, and contraction of this particular abdominal muscle may be one factor capable of preventing and reducing low back pain in sport and in activities of daily living. The function and strength of the transversus abdominis muscle is difficult to measure. The pressure biofeedback unit (PBU) is a device designed to teach and measure transversus abdominis muscle function. The purpose of the present study was to evaluate intra-tester reproducibility of the PBU. METHOD: The study used a test-retest design. Fifteen healthy subjects (mean age 22.2 years, range 19-28 years) with no history of low back pain participated in the study. After two sessions of practising transversus abdominis muscle contraction, its function was measured in prone position with the PBU device placed over the transversus abdominis muscle. Subjects were instructed to draw in the abdominal wall (for example, lifting it away from the device) after a standardized procedure. Two tests were conducted on two different days, with a seven-day interval in between. RESULTS: Coefficient of variance (CV) was 21.0% and the standard deviation (SD) of delta was 1.59. CONCLUSION: The use of the PBU should be improved for scientific purposes. However, the device may have a role in providing biofeedback to assist in the instruction of correct transversus abdominis muscle contraction.

Abdominal Muscles↗
PubMed2000

Effects of a three-month therapeutic exercise programme on flexibility in subjects with low back pain.

BACKGROUND AND PURPOSE: Spinal and muscle flexibility have been studied intensively and used clinically as outcome measurements in the rehabilitation of subjects with low back pain. The results of previous studies are contradictory and there is a lack of longitudinal data on the effects of long term therapeutic exercise on flexibility. METHOD: A controlled experimental study was conducted to determine the effects of progressive therapeutic exercise on spinal and muscle flexibility. Eighty-six chronic low back pain subjects fulfilled the inclusion criteria and were divided into three study groups: (1) intensive training group, (2) home exercise group and (3) control group. The intervention period lasted three months and measurements were performed at both the beginning of the study and immediately after intervention. Follow-up measurements were carried out six and 12 months after baseline. Spinal flexibility was measured with lumbar flexion, extension, spinal lateral flexion and rotation, and muscle flexibility was measured with measurements of erector spinae, hamstring and iliopsoas muscles. Also self-reported outcomes of the Oswestry Index and Borg Scale--Back Pain Intensity were used. Associations between change (pre- to post-treatment) were determined for the dependent variables. RESULTS: The results showed no correlation between flexibility, the Oswestry Index or back pain intensity. After the first three-month period lumbar flexion, extension and spinal rotation decreased among all subjects. Spinal rotation and erector spinae muscle flexibility improved significantly with intensive training. At the nine-month follow-up, erector spine flexibility was still greater than at baseline. Hamstring flexibility increased among the intensive training and home exercise groups from pre- to post-intervention. However, the degree of hamstring flexibility gained during training was subsequently lost following the period without programmed exercise in both training groups. Self-reported outcome variables showed positive changes among the three study groups after the completion of intervention period, but these changes were only able to be maintained during subsequent follow-ups for the intensive training and home exercise groups. CONCLUSIONS: The findings suggest that flexibility does not play an important role in coping with chronic low back pain for subjects whose functional limitations are not severe. Also, it appears that the achieved gains in spinal and muscle flexibility may not be able to be maintained without continued exercise.

Case-Control Studies↗
PubMed2003

Lumbar paraspinal muscle function, perception of lumbar position, and postural control in disc herniation-related back pain.

STUDY DESIGN: A follow-up study evaluating postural control, lumbar movement perception, and paraspinal muscle reflexes in disc herniation-related chronic low back pain (LBP) before and after discectomy. OBJECTIVES: To assess the effect of discectomy on postural control, lumbar perception, and reflex activation of paraspinal muscles during sudden upper limb loading. SUMMARY OF BACKGROUND DATA: Impaired muscle function, postural control, and lumbar proprioception have been observed in LBP. However, they have not been studied in sciatica patients after surgery. METHODS: The study included 20 patients selected for an operation for chronic LBP caused by disc herniation and 15 controls without chronic LBP. The paraspinal muscle responses for upper limb loading during unexpected and expected conditions were measured by surface electromyography. The ability to sense lumbar rotation was assessed in a previously validated motorized trunk rotation unit in the seated position. The postural control was measured with a vertical force platform. Pain, disability, and depression scores were recorded. RESULTS: Patients had poorer lumbar perception (P = 0.012) and postural control (P < 0.05) than did healthy controls. The postural control remained unchanged, but lumbar perception (P = 0.054) and the lumbar feed-forward control (P = 0.043) improved after the surgery. CONCLUSIONS: The results demonstrate impaired lumbar proprioception and postural control in sciatica patients. During short-term follow-up after operative treatment, postural control does not seem to change, but impaired lumbar proprioception and feed-forward control of paraspinal muscles seem to recover.

Chronic Disease↗
PubMed1987

Spinal cord location of the motoneurons innervating the abdominal, cutaneous maximus, latissimus dorsi and longissimus dorsi muscles in the cat.

Horseradish peroxidase (HRP) injections were made in the rectus abdominis, obliquus externus, obliquus internus, transversus abdominis, cutaneous maximus, latissimus dorsi and the longissimus dorsi muscles in the cat. The results showed that motoneurons innervating the obliquus externus, obliquus internus and transversus abdominis muscles were located in greatly overlapping areas of midthoracic, caudal thoracic and upper lumbar spinal segments. These motoneuronal cell groups were present laterally in the ventral horn and at caudal thoracic and upper lumbar levels they bordered on the white matter. The location of the rectus motoneurons differed somewhat from the location of the other motoneuronal cell groups because they were also present at low cervical and upper thoracic levels and in the segments T12 to L3 they were found in the ventral horn medial to the other abdominal muscle motoneuronal cell group. At mid-thoracic levels rectus motoneurons were located in the same area as the other abdominal muscle motoneurons. Latissimus dorsi motoneurons were observed in a large cell group in the ventrolateral part of the ventral horn at the levels caudal C6 to rostral C8. Furthermore they were found in the segments T9 to L3 laterally in the ventral horn which is the same area in which the other abdominal muscle motoneurons except the rectus ones are located. Longissimus dorsi motoneurons were located in the most ventral portion of the ventral horn in all thoracic and upper 4 lumbar segments. The cutaneous maximus motoneurons were found in a cell group, located ventrolaterally in the ventral horn at the edge of the gray and white matter at the level caudal C8-rostral T1. This cell group corresponds to the caudal part of the ventral motor nucleus (VMN) of Matsushita and Ueyama (1973). Interestingly, labeled motoneurons were also present in the VMN after injecting HRP in the abdominal muscles as well as in the caudal (but not in the rostral) parts of the latissimus dorsi muscle but not in the longissimus dorsi injected cases. The possibility whether these motoneurons are labeled because of leakage of HRP to abdominal and caudal latissimus dorsi muscles is discussed. If leakage would not be the case, motoneurons in the VMN may be involved in specific functions of the abdominal muscles, such as the so-called steady state contractions.

Abdominal Muscles↗
PubMedDate not supplied

Effects of muscle electrostimulation during simulated weightlessness.

In a 45-day experiment test subjects were exposed to bed rest with their heads down at -4 degrees C. Twice a day their muscles of the stomach, back, femur, and shin were stimulated with electric current for 25-30 min. The value of muscle tension was close to their maximum voluntary contraction. The main objective was to prevent muscle atrophy and to maintain their trophic and functional state. Physiological measurements were carried out together with morphological, cytochemical, and biometric evaluations. The tissue removed during biopsy from M. soleus 7 days before the test and on the 30th hypokinetic day was used as substrate. Electrostimulation affected favourably the tone and strength of muscles as well as their static and dynamic endurance. Morphological studies showed a positive effect of electrostimulation on the muscle tissue, preventing the development of atrophic processes. During the first post-hypokinetic day orthostatic tolerance increased.

Bed Rest↗
PubMed2003

Medical assistance at the Brazilian juniors tennis circuit--a one-year prospective study.

A prospective study was conducted during one year to evaluate injuries in Brazilian Junior tennis players during the national circuit, in 2001. Male and female athletes in the age categories under 12, under 14, under 16 and under 18 years, all members of The Brazilian Tennis Confederation, participated in the study. Two physiotherapists and/or one physician evaluated the athletes. A total of 280 medical examinations were performed in 151 tennis players who needed medical treatment during the tournaments. The 151 athletes had 1-6 medical treatments during the tournaments and the mean was 1.8 treatment per athlete. The overall incidence was 6.9 medical treatments for every 1,000 games played. Medical assistance tothe athletes was performed on court in 83 (29.6%) occasions, 185 (66.1%) at the medical department and in both in 12 (4.3%) occasions. Retirement of the match was reported in 9 (3.2%) lesions. The most frequent injuries were: muscle contractures (76 - 27.14%), muscle pain/fatigue (36-12.85%), muscle strain (35-12.52%), tendinopathies (20 - 7.14%), cramps (16 -5.71%), ankle sprain (12 -4.28%) and low back pain (10-3.57%). Muscle pathology was the major source of injuries causing the athlete to seek medical assistance. Preventative measures are important to reduce the number of injuries, which may include muscle stretching programs and adequate nutrition and hydration.

Adolescent↗
PubMed1996

Lumbar lordosis and pelvic inclination of asymptomatic adults.

BACKGROUND AND PURPOSE: We examined the association between pelvic inclination and lumbar lordosis during relaxed standing and eight variables thought to contribute to lordosis. SUBJECTS: Ninety subjects (45 men, 45 women) without back pain or a history of surgery were examined. The mean age was 54.8 years (SD = 8.5) for male subjects and 58.9 years (SD = 8.8) for female subjects. METHODS: Multiple linear regression modeling was used to assess the association of pelvic inclination and size of lumbar lordosis in a standing position with age, gender, body mass index, physical activity level, back and one-joint hip flexor muscle length, and performance and length of abdominal muscles. RESULTS: Abdominal muscle performance was associated with angle of pelvic inclination for women (R2 = .23), but not for men. Standing lumbar lordosis was associated with abdominal muscle length in women (R2 = .40), but it was multivariately associated with length of abdominal and one-joint hip flexor muscles and physical activity level in men (R2 = .38). No correlation was found between angle of pelvic inclination and depth of lumbar lordosis in a standing position. CONCLUSION AND DISCUSSION: Neither univariate nor multivariate regression models account for variability in the angle of pelvic inclination or size of lumbar lordosis in adults during upright stance; no correlation was found in standing between these two variables. The use of abdominal muscle strengthening exercises or stretching exercises of the back and one-joint hip flexor muscles to correct faulty standing posture should be questioned.

Abdominal Muscles↗
PubMed2004

Valley sign in Becker muscular dystrophy and outliers of Duchenne and Becker muscular dystrophy.

Valley sign has been described in patients with Duchenne muscular dystrophy (DMD). As there are genetic and clinical similarities between DMD and Becker muscular dystrophy (BMD), this clinical sign is evaluated in this study in BMD and DMD/BMD outliers. To evaluate the sign, 28 patients with Becker muscular dystrophy (BMD), 8 DMD/BMD outliers and 44 age-matched male controls with other neuromuscular diseases were studied. The sign was examined after asking patients to abduct their arms to about 90 cent with hands directed upwards; the muscle bulk over the back of the shoulders was observed. The sign was considered positive if the infraspinatus and deltoid muscles were enlarged and between these two muscles, the muscles forming the posterior axillary fold were wasted as if there were a valley between the two mounts. Twenty-five BMD patients and 7 DMD/BMD outliers had positive valley sign. However, it was less remarkable in comparison to DMD. It was absent in all the 44 controls. It was concluded that the presence of valley sign may help in differentiating BMD from other progressive neuromuscular disorders of that age group.

Adolescent↗
PubMed1990

[Computerized tomography findings in malignant progressive Duchenne muscular dystrophy].

A correct diagnosis of progressive muscle dystrophy type Duchenne is important for consultation of the family of patients. The muscles of neck, shoulder, back, pelvis and legs of 23 patients were examined by computed tomography. The density of selected muscles were measured and compared with that of normal probands. Typical changes in the density-pattern were found. It is show, that the measurement of the density-pattern of muscles in pelvis and legs is sufficient for a sure diagnosis of progressive muscle dystrophy Duchenne.

Adolescent↗
PubMed1989

The relationship of extraneous movements to lumbar paraspinal muscle activity: implications for EMG biofeedback training applications to low back pain patients.

Within recent years clinicians and researchers have applied paraspinal EMG biofeedback procedures during static and dynamic movement retraining of chronic low back pain patients. Most of these applications make use of surface electromyography, an approach complicated by the fact that the erector spinae muscles are deeply situated. This descriptive study reveals that extraneous movements, such as neck flexion and pelvic rotation, can elicit profound activity from percutaneously placed EMG electrodes while little change is seen at the skin surface. The implications of these observations for the use of EMG feedback to remediate low back pain are discussed.

Adult↗
PubMed1996

Can strong back extensors prevent vertebral fractures in women with osteoporosis?

OBJECTIVE: To determine the influence of back extensor strength on vertebral fractures in 36 women with osteoporosis. DESIGN: We conducted a cross-sectional study of female patients with osteoporosis by assessing anthropometric variables, bone mineral density, muscle strength, level of physical activity, and radiographic findings in the spine. MATERIAL AND METHODS: The 36 study subjects with osteoporosis, who ranged from 47 to 84 years of age, satisfied specific inclusion and exclusion criteria that minimized confounding factors related to pathophysiologic features, diet, and medications. A physical activity score was determined for each subject on the basis of daily physical activities relating to homemaking, occupation, and sports. RESULTS: The range of the physical activity scores-from 2 to 13-indicated that no subject was involved in unusually demanding physical activities. Bone mineral density values ranged from 0.49 to 0.92 g/cm2. Thoracic kyphosis ranged from 31.0 to 84.0 degrees. Isometric strength of the back extensor muscles ranged from 7.3 to 34.0 kg. Statistical analysis demonstrated a significant negative correlation between the strength of the back extensor muscles and thoracic kyphosis. Significant negative correlations were also found between back extensor strength and the number of vertebral compression fractures and between bone mineral density and the number of vertebral fractures. CONCLUSION: The negative association between back extensor strength and both kyphosis and number of vertebral fractures suggests that increasing back strength may prove to be an effective therapeutic intervention for the osteoporotic spine. In persons with stronger back muscles, the risk of vertebral fractures will likely decrease.

Aged↗