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In a number of caimans (Caiman sclerops) we were unable to find traces of myoglobin in any of the histologically clearly cross-striated cardiac and skeletal muscles using spectrometric methods. The red colour of the heart is due to a high concentration of cytochrome c. This substance was also found in the muscles of the neck, back, tail, and the anterior extremities.
The area occupied by the intrinsic postvertebral muscles varies in the different region of the back. This is associated with variations in the densities of muscle spindles in successive segments of the three columns of muscle. In the thoracic region, the lateral column has the highest density of spindles, whilst the intermediate and medial columns have steadily less. The attachment of iliocostalis and longissimus thoracis muscles to the ribs is such that contraction of these muscles can produce changes in the costotransverse joints. Conversely, movement in these joints might stimulate stretch receptors in the postvertebral muscles. There is collateral innervation of the costotransverse joints and the postvertebral muscles of the thoracic region by the posterior ramus. The finding of high densities of spindles in the thoracic region would therefore seem to support the hypothesis that these muscles probably monitor postural activity of the back as well as the rib cage.
The ability of myogenic cells to migrate perpendicular to the long axis of freely autografted muscles was examined. Rat extensor digitorum longus muscles were divided, and one half was devitalized by repeated freezing in liquid nitrogen while the other half was kept viable in physiologic saline. The halves were reunited with sutures and grafted back into the original muscle bed. At intervals between 5 and 25 days the grafts were removed and examined histologically for the presence of myotubes within the devitalized region. Myotubes were first seen in the devitalized half 10 days postgrafting with the maximum number of myotubes observed after 12 to 15 days. These results indicate that myogenic cells are capable of migration perpendicular to the long axis of the muscle fibers in an autograft.
We review new data derived from careful dissection studies on the macroscopic anatomy, innervation and function of the lumbar muscles, as well as information on the fibres in these muscles. The new findings correct previous misconceptions of the functional anatomy of the lumbar muscles. The innervation and function of the erector spinae and multifidus muscles are so different that they cannot be classified as a single unit. The new interpretation of the innervation of multifidus muscle is of importance, for example, for the neurophysiological examination of the lumbar muscles. The relative number of the slow and fast type of muscle fibres in lumbar muscles varies considerably, and selective atrophy of the fast fibres seems to ensue from inactivity, not only in patients with back pain but also in sedentary controls. The atrophy may be corrected by adequate exercise. Both the fibre type composition and degree of atrophy may well influence a person's susceptibility to low back pain arising from the muscles.
Abdominal exercises are prescribed for both the prevention and treatment of low back injury. However, these exercises sometimes appear to have hazardous effects on the lumbar spine. The purpose of this study was to identify quantitatively abdominal exercises that optimize the challenge to the abdominal muscles (rectus abdominis, external oblique, internal oblique) but impose minimal load penalty to the lumbar spine. Nine volunteers performed 12 different abdominal exercises. For a given task the maximum abdominal muscle EMG value was divided by the maximum compression value, resulting in an abdominal challenge versus spinal compression cost index. In general, the partial curl-ups generated the highest muscle challenge-to-spine cost indices. However, those exercises that generated the best challenge-to-cost indices did not necessarily record the lowest compression levels along with the highest EMG activations. No single exercise was found that optimally trained all of the abdominal muscles while at the same time incurring minimal intervertebral joint loads. It was concluded that a variety of selected abdominal exercises are required to sufficiently challenge all of the abdominal muscles and that these exercises will-differ to best meet the different training objectives of individuals.
OBJECTIVES: To further the understanding of stature recovery in subjects with and without chronic low back pain (CLBP) and to determine the relations among stature recovery, paraspinal muscle activity, and perceived pain and disability. DESIGN: A case-control study in which stature loss and recovery were assessed in subjects with and without CLBP after a 20-minute loaded walking task (10% of body mass). Group differences in pain, disability, and paraspinal muscle activity were also assessed. SETTING: A university laboratory. PARTICIPANTS: Twenty subjects with CLBP were matched (age, sex, body mass, physical activity level) with 20 controls who were recruited through notices in the university, general community, and local Primary Care Trust. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stature changes and integrated electromyograms of the paraspinal muscles during a loading and unloading period were assessed. RESULTS: Stature changes after loading did not differ between groups ( P <.05). Subjects with CLBP recovered significantly less stature during unloading than did the controls ( P <.05). Paraspinal muscle activity correlated negatively with stature recovery ( P <.05). Relations among stature recovery, pain, and disability were shown ( P <.05). CONCLUSIONS: The elevated paraspinal muscle activity exhibited by the CLBP group increased compression on the intervertebral disks and diminished their ability to recover the height lost through loaded exercise. Further research is required to establish whether a change in paraspinal muscle activity is associated with corresponding changes in stature recovery, and if this has any clinical implications by reducing pain and disability.
Proprioceptive information from paraspinal tissues including muscle contributes to neuromuscular control of the vertebral column. We investigated whether the history of a vertebra's position can affect signalling from paraspinal muscle spindles. Single unit recordings were obtained from muscle spindle afferents in the L6 dorsal roots of 30 Nembutal-anaesthetized cats. Each afferent's receptive field was in the intact muscles of the low back. The L6 vertebra was controlled using a displacement-controlled feedback motor and was held in each of three different conditioning positions for durations of 0, 2, 4, 6 and 8 s. Conditioning positions (1.0-2.2 mm dorsal and ventral relative to an intermediate position) were based upon the displacement that loaded the L6 vertebra to 50-60% of the cat's body weight. Following conditioning positions that stretched (hold-long) and shortened (hold-short) the spindle, the vertebra was repositioned identically and muscle spindle discharge at rest and to movement was compared with conditioning at the intermediate position. Hold-short conditioning augmented mean resting spindle discharge by +4.1 to +6.2 impulses s(-1); however, the duration of hold-short did not significantly affect this increase (F(4,145) = 0.49, P = 0.74). The increase was maintained at the beginning of vertebral movement but quickly returned to baseline. Conversely, hold-long conditioning significantly diminished mean resting spindle discharge by -2.0 to -16.1 impulses s(-1) (F(4,145) = 11.23, P < 0.001). The relationship between conditioning duration and the diminished resting discharge could be described by a quadratic (F(1,145) = 9.28, P = 0.003) revealing that the effects of positioning history were fully developed within 2 s of conditioning. In addition, 2 s or greater of hold-long conditioning significantly diminished spindle discharge to vertebral movement by -5.7 to -10.0 impulses s(-1) (F(4,145) = 11.0, P < 0.001). These effects of vertebral positioning history may be a mechanism whereby spinal biomechanics interacts with the spine's proprioceptive system to produce acute effects on neuromuscular control of the vertebral column.
An angiosome is a composite block of tissue that is supplied anatomically by source (segmental or distributing) vessels that span between the skin and bone. In addition to supplying the deep tissues, the source vessels of these angiosomes supply branches to the overlying skin, which pass either between the deep tissues or through the deep tissues, usually muscle, to pierce the outer layer of the deep fascia, usually at fixed skin sites. Hence, perforator flaps, when dissected to the underlying source vessels, involve tracing vessels either between the deep tissues, whether muscle tendon or bone, or through the deep tissues, usually muscle.
This study examined the time course of recovery from nerve injury on energy state assessed by phosphorus-31 magnetic resonance spectroscopy and local circulation dynamics by fluorine-19 magnetic resonance spectroscopy in skeletal muscles of rats. The hindlimb muscles that had undergone unilateral sciatic nerve compression for 2 wk (CN) were compared with sham-operated (SO) muscles and with muscles that had the compression removed after 2 wk and were allowed to recover for 4 wk (R4) or for 6 wk (R6). The energy state and local circulation dynamics of CN muscles were less than those of SO muscles (P < 0.01). The energy state of R4 muscles remained at levels similar to CN muscles, whereas the local circulation dynamics improved but not back to SO values. In R6 muscles, both parameters returned to SO values. These results showed that the recovery processes of circulation precede those of energy state in skeletal muscles.
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When treating degeneration diseases, endoprosthesis operations are performed widely. The results of the treatment depend not only on the operating technique and up-to-date prostheses but also on the correct postoperative rehabilitation, applied in particular the kinesitherapeutic means. The aim of the research was to establish the effect of postoperative rehabilitation with wide use of kinesitherapeutic means in sanatorium conditions on the functional capacity of the joint operated on as well as on the general condition of the patient. The research has been done at the traumatology department of the Sanatorium "Versme" in Birstonas. The patients were prescribed a complex of kinesitherapeutic means, i.e. curative gymnastic exercises performed for 45 min twice a day, water kinesitherapy, self-dependent isometric exercises, walking and manual massage. Clinical examination of 30 patients has been undertaken on the first and last day of their rehabilitation in the sanatorium. The mobility of the hip joint, muscle strength and circumference of the thigh have been measured. The patient's tolerance to physical load, his/her sensitiveness to pain, the patient's rate of walking and self-care have been estimated. It has been established that kinesitherapeutic means applied during the 30 day course of rehabilitation undergone in the Sanatorium increased the amplitude (flexion and drawing back) of the joint operated on, the strength of quadriceps muscle femoris and the strength of drawing back and back femoral muscles, as well as decreased sensitiveness to pain and improved the rate of walking and functional class (p < 0.001). The circumference of the femoral muscle and functional independence of the patients remained unchanged. The functional capacity of the endoprothesized hip joint of the patients improved to some extent irrespective of the section performed during the operation as well as irrespective of the sex and age of the patients.
Twenty-three male patients who had chronic nonspecific low-back pain were asked to record the amount of pain they felt on an arbitrary scale while lifting light weights in different directions. During the lifts their intraabdominal pressures were recorded with an intragastric transducer. The patients who experienced extra pain during the lift had higher rises of pressure than both normal controls and those patients who did not experience extra pain. The available evidence suggests that this pressure rise may be a response to low-back pain and may be used as a method of objectively measuring that pain.
Diagnosis of piriformis syndrome is difficult and its precise definition is highly controversial. In this article, the authors present the case of a patient who had clinical features suggestive of piriformis syndrome. During surgery the patient was found to have a rare variation in anatomical structures, in which the peroneal nerve was displaced by the piriformis muscle. Surgical decompression did not alleviate the patient's symptoms.
In 1993, the Ministry of Labour and Welfare had to make compensation payments to 11,308 workers (equivalent to 7.22%) for their sickness caused by lifting and moving heavy objects. This figure tends to be increasing each year. From survey of working conditions, we found that most workers beaned their back in order to lift heavy objects repeatedly in each working day. Therefore, it is important to educate and train our workers to change their working habits in order to solve this problem. This study was conducted within a targeted group of 40 workers, aged between 20-30 years, whose duties are to lift soft drink cases. The study involved observing the workers' way of performing their work, interviewing them regarding the pain in different parts of the body, and testing of their muscle strength. We discovered that these workers beaned their back when lifting soft drink cases repeatedly and thus experienced moderate to medium levels of back pain. Moreover, their muscle strength weakened at the end of each working day. We then undertook training courses, educating them and showing them how to do it right. The workers have accordingly implemented the new method they have learned in performing their daily responsible tasks. Follow-up studies to assess the results were made continuously and we were pleased to learn that back pain problem has dramatically decreased. A comparison of muscle strength before and after work showed that the decrease of back muscle strength was less in the experimental group than in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
It is not always clear what causes acute back pain. It may result from injuries to muscles, ligaments, bones, joints and discs in the back or to injury to a combination of these structures. Increased muscle tension, for whatever reason, can increase pain. It is not usually possible to make a precise diagnosis, but in most cases the pain settles in few days or weeks. If pain persists it is important to follow up with your doctor.
1. By supplying pulses to different subdivisions of the ventral nerve roots in rotation it was possible to obtain smooth contractions of cat soleus with low rates of stimulation.2. After contracting isometrically the muscle was subjected to ;step' changes in tension after which it lengthened or shortened isotonically.3. Isotonic lengthening movements usually began relatively slowly but proceeded with increasing velocity; this acceleration was most conspicuous when low rates of stimulation were used.4. At low rates of stimulation the isotonic lengthening movement often continued beyond the length at which the muscle could have generated that tension in an isometric contraction. The muscle then shortened slowly back toward that length.5. Isotonic shortening movements began relatively rapidly, but as shortening continued the movement became slower, and often had an irregular oscillatory course.6. The isotonic movements are discussed in relation to the sliding filament theory of muscle contraction.7. The compliance of the series elastic elements was calculated from the relative amplitudes of the ;step' changes in tension and length. The stiffness of this component increased with increasing muscle tension.
In acute decerebrate cat, stimulation of the dorsal tegmental field (DTF) of the caudal pons along its midline and the medial pontine reticular formation (mPRF) evokes generalized suppression of postural muscle tone. In this study, the effects of stimulation of the DTF area were compared with those evoked by stimulating the mPRF unilaterally or bilaterally. By stimulating the mPRF bilaterally, simultaneous suppression of tonic activities in the neck, lumbar back, forelimb and hindlimb muscles, bilaterally, was evoked as that evoked by stimulating the DTF area alone.