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Reciprocal inhibition between forearm muscles in spastic hemiplegia.

We studied reciprocal inhibition of H-reflexes in the forearm flexor and extensor muscles in 14 patients with spastic hemiplegia secondary to a focal cerebral lesion and 14 normal volunteers. In the spastic limb, the Hmax/Mmax ratio was increased in both flexor and particularly extensor wrist muscles. The 3 normal inhibitory phases of reciprocal inhibition between extensor and flexor forearm muscles were markedly reduced on the spastic side of patients. The early disynaptic phase showed the greatest alteration. Reduced or absent inhibition between forearm muscles associated with increased spinal motoneuron excitability may be typical to spastic hemiplegia.

Brain Diseases↗

Asymmetry of forearm rolling as a sign of unilateral cerebral dysfunction.

We compared the reliability of asymmetry of forearm rolling (rotation of one forearm around the other in front of the torso) as a sign of unilateral cerebral dysfunction with that of other standard clinical tests. We studied 62 patients with radiologically confirmed unilateral cerebral lesions and 20 control subjects with normal imaging. Asymmetric forearm rolling was the most sensitive indicator of unilateral hemispheric disease (85%). This simple test is a useful addition to the neurologic examination.

Adult↗

Osteosarcoma of the hand and forearm: experience of the Cooperative Osteosarcoma Study Group.

BACKGROUND: Osteosarcoma is extremely rare in the hand and forearm. Therefore, only limited data are available for planning treatment or predicting the outcome and prognosis of osteosarcoma in the peripheral upper extremity. METHODS: Epidemiological, clinical, and histopathologic data were analyzed in 39 patients with osteosarcoma of the forearm or hand who were enrolled in studies of the Cooperative German-Austrian-Swiss Osteosarcoma Study Group from 1977 to December 2000. In patients with high-grade osteosarcoma, the treatment entailed surgical resection in combination with chemotherapy, whereas patients with low-grade osteosarcoma underwent only surgery. RESULTS: The 5-year overall survival rate among the 33 patients with high-grade central osteosarcoma of the distal upper extremity was 86.2% +/- 6.4%. The 5-year event-free survival rate was 65.4% +/- 9.6%. Five of the eight patients with secondary metastases were in remission at the time of analysis. Four patients died of their disease, and two patients died of chemotherapy-related complications. The mean overall survival rate was 88.0% +/- 6.5% in patients treated by wide or radical tumor resection and was 75.0% +/- 21.7% in patients with nonwide margins of resection. Whether amputation or local resection was performed had no significant influence on the prognosis. All six patients whose osteosarcoma was not classified as high-grade central osteosarcoma were in remission at the time of analysis. CONCLUSIONS: The results demonstrate a remarkably high survival rate for patients with high-grade osteosarcoma of the hand and forearm and confirm that multiagent chemotherapy in combination with wide excision is a highly effective treatment for this malignant tumor.

Adolescent↗

Plasma malondialdehyde increases transiently after ischemic forearm exercise.

UNLABELLED: Exercise and ischemia-reperfusion (I-R) have previously been shown to induce oxidative stress in skeletal muscle. Previous studies have demonstrated conflicting results when exercise-induced oxidative stress has been measured using plasma carbonyls, specifically malondialdehyde (MDA). These conflicting results likely stem from the timing and method utilized to measure plasma carbonyls. PURPOSE: To determine the concentration and timing of aldehyde and ketone generation after ischemic forearm exercise utilizing HPLC analysis. METHODS: Plasma carbonyls, including MDA, 17-beta-estradiol, and lactate, were measured after a forearm ischemic exercise test (FIT) in males and females (in both phases of their menstrual cycle). Blood flow was occluded to the forearm, and six cycles of maximal isometric handgrip exercise were executed using a 9:1, duty:rest cycle, for 60 s. Blood samples were collected pre, immediately post, and 1, 3, and 10 min post-FIT. RESULTS: Plasma MDA increased similarly for both males and females immediately post and 1 min post-FIT (P<0.05) and returned to baseline levels by 3 min post-FIT. Ischemic exercise did not alter plasma concentrations of other measured carbonyls, and gender and menstrual cycle did not influence any measured variable (P>0.05), except for lactate concentrations, which increased more for males (P<0.05). Force was higher for males at all time points (P<0.05); however, there was no effect of gender on percent fatigue. CONCLUSIONS: Future studies must consider sampling times after metabolic stress in order to quantify changes in MDA concentration.

Adult↗

Nitric oxide-mediated vasodilatation is decreased in forearm resistance vessels in patients with coronary spastic angina.

It has been reported that coronary endothelial dysfunction is associated with the pathogenesis of coronary spasm, and that endothelial nitric oxide (NO) mediated vasodilatation was decreased in coronary epicardial arteries in patients with coronary spastic angina (CSA). However, there are few reports about the endothelial function in peripheral resistance vessels of patients with CSA, so the present study investigated the role of NO in forearm resistance vessels in such patients. The responses of forearm blood flow to acetylcholine (ACh; 8-24 microg/min) and sodium nitroprusside (SNP; 0.4-1.2 microg/ml) infusions was examined using plethysmography, and subsequently the responses to ACh after an infusion of N(G)-monomethyl-L-arginine (L-NMMA; 4 micromol/min, for 5 min) in 17 patients with CSA and 17 age- and sex- matched controls. The vasodilator responses to ACh and SNP were comparable between the 2 groups (p=NS). L-NMMA significantly suppressed the vasodilator responses to ACh in controls (p<0.05), but there was no significant difference in the responses to ACh before and after infusion of L-NMMA in patients with CSA (p=NS). These results indicate that endothelial NO-mediated vasodilatation is decreased in the forearm resistance vessels of patients with CSA.

Acetylcholine↗

The combined sensate radical forearm and iliac crest free flaps for reconstruction of significant glossectomy-mandibulectomy defects.

The loss of motor and sensory function of the tongue following ablative surgery has a devastating effect on oral function. At the present time, there is no way to restore lost tongue musculature following partial glossectomy. The use of sensate cutaneous flaps has been shown to restore sensory feedback to reconstructed areas of the oral cavity. No single composite flap supplies a sensate soft-tissue component together with an osseous component of sufficient bone stock for functional mastication. In this article, the combination of the radial forearm free flap with the iliac crest osteocutaneous or osteomyocutaneous free flap is reported. The radial forearm free flap was used to resurface the resected portion of the tongue to provide maximum mobility and sensation. The lingual nerve was the recipient nerve for anastomosis to the antebrachial cutaneous nerves in all but one case. The iliac bone was used to reconstruct the mandible, with the iliac skin paddle or the internal oblique muscle used to reconstruct the neoridge. This combination of flaps was used in 10 patients. There was one flap failure due to vascular kinking from "piggybacking" the iliac crest to the distal end of the radial forearm flap. As a result, the use of two separate sets of recipient vessels is now advocated. Although a single composite free flap offers an excellent form of oromandibular reconstruction in most cases, it has been shown that oral function deteriorates when large areas of anesthesia are present in the oral cavity. We believe that this combination of two free flaps offers an opportunity for superior function in select patients with significant glossectomy and/or large mucosal defects.

Anastomosis, Surgical↗

Closed reduction and percutaneous fixation of supracondylar fracture of the humerus and ipsilateral fracture of the forearm in children.

We treated 22 children with a supracondylar fracture of the humerus and an ipsilateral fracture of the forearm by closed reduction and percutaneous fixation. There were four Gartland type-II and 18 Gartland type-III supracondylar fractures of the humerus. There were fractures of both bones of the forearm in 16 and of the radius in six. Both the supracondylar and the distal forearm fractures were treated by closed reduction and percutaneous fixation. The mean follow-up time was 38.6 months. At the latest follow-up there were 21 excellent or good results and one fair result. There were no cases of delayed union, nonunion or malunion. Five nerve injuries were diagnosed on admission and all recovered spontaneously within eight weeks. No patient developed a compartment syndrome.

Bone Wires↗

Immobilisation of forearm fractures in children: extended versus flexed elbow.

Redisplacement of unstable forearm fractures in plaster is common and may be the result of a number of factors. Little attention has been paid to the influence of immobilisation with the elbow extended versus flexed. We prospectively treated 111 consecutive children from two centres with closed forearm fractures by closed reduction and casting with the elbow either extended (60) in China or flexed (51) in Israel. We compared the outcome of the two groups. There was no statistically significant difference in the distribution of the age of the patients, the site of fracture or the amount of angulation and displacement between the groups. During the first two weeks after reduction, redisplacement occurred in no child immobilised with the elbow extended and nine of 51 children (17.6%) immobilised with the elbow flexed. Immobilisation of unstable forearm fractures with the elbow extended appears to be a safe and effective method of maintaining reduction.

Casts, Surgical↗

Forearm bone mineral density in 1294 middle-aged women: a strong predictor of fragility fractures.

The aim of this study was to find out whether a single bone mineral density (BMD) measurement performed at middle age in early postmenopausal women could predict future fragility fractures. The Malmo Preventive Project, a population-based cardiovascular prevention study, included a subgroup of 1294 women, mean age 53, on which forearm BMD measurements were made using single-photon absorptiometry (SPA). Risk ratios (RRs) were calculated for an age-adjusted decrease in BMD of one standard deviation. During the 9-yr follow-up, 65 women sustained 86 fractures. The data were analyzed with Cox's proportional hazard analysis. The relative risk for sustaining any fragility fracture were 2.02 (95% confidence interval [CI] = 1.56-2.61) and 1.62 (CI = 1.26-2.08) at the distal and proximal forearm BMD measurement, respectively. The risk increase was significant for forearm fracture at the distal BMD level (RR = 1.94; range = 1.40-2.68) and at the proximal BMD level (RR = 1.77; range = 1.29-2.42). Our study is one of the first to show that a BMD measurement in a population at age 50 can predict fracture over almost 10 yr, indicating that early identification of women with increased fracture risk is possible, and the cost-effectiveness of such an approach needs to be further evaluated.

Absorptiometry, Photon↗

A laboratory study of the effects of wrist splint orthoses on forearm muscle activity and upper extremity posture.

OBJECTIVE: To evaluate the effects of wrist splint orthoses (WSOs) on forearm muscle activity and upper extremity/torso postures. BACKGROUND: WSOs are ubiquitous in industry, but the literature as to their biomechanical effects is limited. METHOD: Study 1: Participants performed single-plane wrist exertions with or without a WSO while the electromyographic (EMG) activity of the flexor carpi radialis, flexor carpi ulnaris, and extensor carpi ulnaris was captured. Study 2: Participants performed simple computer jumper installation tasks with or without a WSO while upper extremity/torso postures were recorded. RESULTS: Study 1: A significant interaction between WSOs and wrist angle was observed in the response of forearm muscles (e.g., normalized EMG of the flexor carpi radialis increased from 4.2% to 15.9% as flexion increased from 0 degree to 36 degrees in the orthosis conditions, whereas in the no-orthosis condition it remained approximately 5% at all wrist flexion angles). Study 2: WSOs were found to effect wrist, torso, and shoulder postures, with the orthoses creating a 48% decrease (36 degrees vs. 18.6 degrees) in wrist flexion and 80% decrease (15 degrees vs. -3 degrees) in ulnar deviation but at a cost of increased shoulder abduction of 22% (36.5 degrees vs. 44.5 degrees) and increased lateral bend of torso of 30% (6 degrees vs. 7.8 degrees). CONCLUSIONS: WSOs increased forearm muscle activity at large wrist deviation angles and induced awkward shoulder postures in tasks requiring significant wrist deviation. APPLICATION: Use of WSOs in occupational settings should be carefully considered relative to task requirements, as orthoses may do more harm than good.

Adult↗

Forearm venous distensibility in relation to severity of symptoms and hemodynamic data in patients with congestive heart failure.

The distensibility of the forearm veins in 24 patients with congestive heart failure was studied by occlusion plethysmography. Relationships between forearm venous distensibility and symptoms, hemodynamic data obtained by right heart catheterization and plasma levels of vasoactive hormones were evaluated. Forearm venous pressure (VP) and volume change (delta V) were measured simultaneously by the venous occlusion technique with strain gauge plethysmography. The relationship between venous pressure and volume change was fitted by the equation VP = c* exp (k* delta V) (r = 0.98 +/- 0.01) and the venous stiffness constant (k) was calculated. Venous volume change at a venous pressure of 20 mmHg (V20) was also measured as another index of venous compliance. The pressure-volume curve of the peripheral veins shifted leftward on the volume axis and the stiffness constant (k) increased as the New York Heart Association functional class grade increased. Mean pulmonary arterial pressure and pulmonary vascular resistance were closely related to k (r = 0.74, p less than 0.001; r = 0.73, p less than 0.001, respectively), and less closely to V20 (r = -0.56, p less than 0.004; r = -0.59, p less than 0.002, respectively). K and V20 were also related to stroke index (r = -0.57, p less than 0.004; r = 0.44, p less than 0.03, respectively) and stroke work index (r = -0.47, p less than 0.02; r = 0.45, p less than 0.03, respectively). K was also related to heart rate (r = 0.55, p less than 0.007), pulmonary capillary wedge pressure (r = 0.54, p less than 0.02), right atrial pressure (r = 0.51, p less than 0.02), cardiac index (r = -0.45, p less than 0.03), and systemic vascular resistance (r = 0.45, p less than 0.03). Both indexes were related to the plasma level of norepinephrine (r = 0.64, p less than 0.008; r = -0.52, p less than 0.04, respectively). We concluded that the venous tone was related to the severity of heart failure, especially to the symptoms, pulmonary arterial pressure and plasma concentration of norepinephrine, and that the venous stiffness constant, k, was a better parameter with which to assess peripheral venous tone.

Aged↗

A simple ergometer for 31P NMR spectroscopy during dynamic forearm exercise in a whole body magnetic resonance imaging system.

The purpose of this study was to construct a simple ergometer for the 31P NMR spectroscopic study of dynamic forearm exercise in a whole body magnetic resonance imaging system and to evaluate the total system and the physiological response to this type of exercise using a multistage protocol. The system consisted of a completely nonmagnetic assembly including a rope, pulley and weights. The work of lifting weights was quantitated. The exercise protocol of 1-min increments in work load enabled subjects to reach maximal effort. Phosphocreatine decreased linearly with an increase in work load and was accompanied by a fall in pH and an increase in lactate level in the antecubital vein of the exercising forearm; concomitantly, there was a slight increase in whole body oxygen uptake and heart rate. Spectroscopy gave reproducible results using this exercise protocol. These results demonstrate that this system provides a reliable means for performing 31P magnetic resonance spectroscopy studies during forearm exercise.

Adenosine Triphosphate↗

Trauma to arteries of the forearm.

Trauma to arteries of the forearm corresponds to 20% of total arterial trauma. The authors analyzed 24 patients with non iatrogenic trauma of the forearm arteries, cared for from January 1987 to December 1990. All patients were male, trauma by penetrating instrument was the most frequent, with 21 cases (87.5%), absence of pulses was the most frequent clinical manifestation (62.5%), fifteen patients did not present ischemic manifestations (54.2%) and half of the patients did not exhibit neurological symptoms. Injury to only one artery was found in 11 cases, five of them in the radial artery (20.8%), five in the ulnar artery (20.8%) and one in the interosseous artery (4.2%). Concurrent injury to the radial and ulnar arteries was found in 13 cases (54.1%). Regarding nervous impairment, injury to the radial nerve was found in four cases (16.6%) and of the median and ulnar nerves, one case in each (4.1%). All patients with concurrent injury to the ulnar and radial arteries (13) were submitted to arterial restoration. The 11 patients with injury to a sole artery of the forearm were managed as follows: ligature of the interosseous artery in one case, ligature of the radial artery in four cases, raphe of the radial artery in one case, ligature of the ulnar artery in three cases, restoration of the ulnar artery using a segment of the v. saphena in the two cases in which the Allen test had been positive. One patient died in the immediate postoperative period as a result of multiple organ failure due to polytraumatism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Effect of warning signal on reaction time and EMG activity of the biceps brachii muscle in elbow flexion and forearm supination.

Using a reaction time (RT) task, the biceps brachii muscle was investigated in five healthy subjects to determine whether EMG in the initial phase of activity is dependent upon the direction of movement, i.e., elbow flexion and forearm supination, and/or influenced by the presence or absence of warning signal. Results showed that in the presence of warning EMG-RT of forearm supination was faster than that of elbow flexion, and that the reverse occurred in the absence of warning. The warning signal significantly reduced EMG-RT of both movements and the reduction of EMG-RT was larger in supination than flexion. Compared to forearm supination, large amplitude potentials were observed during elbow flexion. The warning suppressed EMG activities of both movements within 30 msec after their initiation. The present study indicates that the biceps brachii muscle exhibits a motor response program specific to the direction of movements and that preparatory set conditioned by warning shortens RT and also suppresses EMG activities.

Action Potentials↗

Electromyographic study of the elbow flexors and extensors in a motion of forearm pronation/supination while maintaining elbow flexion in humans.

Activities of the elbow flexors (biceps brachii, BB; brachialis, B; brachioradialis, BR) and extensors (triceps brachii, TB) in a motion of forearm pronation/supination with maintenance of elbow flexion (PS-movement) in nine healthy human subjects were studied by electromyography (EMG). The subject performed the PS-movement slowly or quickly with or without a load extending the elbow. In the slow PS-movement, an increase and decrease of EMG activities during supination and pronation, respectively, were seen in BB and the reverse was in B. A clear increment of EMG activities in BB accompanied with a reduction of EMG activities in B and/or BR, and the reverse were often observed. The contraction level and gain with the forearm supine were higher and larger than those with the forearm prone, respectively, in BB and the reverse was in B and BR. In a series of the quick PS-movement, alternating increases of EMG activities between BB and the other flexors (B and BR) were seen. Since TB showed no EMG activities throughout the experiment, it is suggested that reciprocal contractions between BB and the other flexors, which produce a complementary force in flexion direction, enable motions of pronation/supination with maintenance of flexion. Contraction properties of the flexors were discussed.

Adult↗

Rerouting of the biceps brachii for paralytic supination contracture of the forearm in tetraplegia due to trauma.

Six tetraplegic patients (eight forearms) who had a supination contracture were evaluated after lengthening and rerouting of the biceps brachii. Preoperatively, the mean range of supination and pronation of the forearm was 85 and 14 degrees, respectively. Pronation increased a mean of 75 degrees without affecting the strength of flexion or the flexion-extension arc of motion of the elbow. The forearms that had a satisfactory result had a mean active range of supination of 69 degrees, while those that had a poor result had no active supination. The mean duration of follow-up was twenty-seven months (range, twelve to seventy-two months). The result was considered satisfactory for six limbs and unsatisfactory for two. Functional gains were made in the patients' ability to feed and groom themselves, in their ability to tend to personal hygiene, and in writing and typing skills when the dominant extremity was treated. The results were less predictable for the non-dominant extremity. The maximum gain in the range of motion occurred at three months and the maximum functional gain, by six months.

Activities of Daily Living↗

Compartment syndrome in the forearm following fractures of the radial head or neck in children.

A volar compartment syndrome of the forearm was identified following a minimally displaced or angulated fracture of the radial head or neck in three children. The fractures were due to a fall from a bed or from a standing height on an outstretched hand. All three patients had symptoms and signs that were consistent with elevated intracompartmental pressure in the forearm when they were first examined, twelve to twenty-four hours after the injury, and all were managed with an emergency fasciotomy of the forearm. The radial fracture was treated without reduction in the first patient, with manipulative closed reduction in the second patient, and with open reduction and stabilization with Kirschner wires in the third patient. All three patients had a full functional recovery.

Child↗

Effects of radial head excision and distal radial shortening on load-sharing in cadaver forearms.

BACKGROUND: The present study was performed to measure changes in radioulnar load-sharing in the cadaveric forearm following two orthopaedic surgical procedures that often have varying results: radial head excision and distal radial shortening. A better understanding of the biomechanical consequences of those procedures could aid surgeons in obtaining a more satisfactory clinical outcome. METHODS: Miniature load-cells were inserted into the proximal part of the radius and the distal part of the ulna in twenty fresh-frozen cadaveric forearms. Load-cell forces, radial head displacement relative to the capitellum, and local tension within the central band of the interosseous membrane were measured simultaneously as the wrist was loaded to 133.5 N in neutral pronation-supination and neutral radioulnar deviation. Testing was repeated after incremental distal radial shortening and after removal of the radial head. RESULTS: With the elbow flexed to 90 degrees and in valgus alignment (the radial head in contact with the capitellum), the mean force in the distal part of the ulna was 7.1% of the applied wrist force and the mean force in the interosseous membrane was 4.0%. With the elbow in varus alignment (a mean initial gap of 1.97 mm between the radial head and the capitellum), the respective mean values were 27.9% and 51.2%. After excision of the radial head, the mean force in the distal part of the ulna increased to 42.4% of the applied wrist force and the mean force in the interosseous membrane increased to 58.8%, in both varus and valgus elbow alignment. The mean distal ulnar force increased with progressive distal radial shortening in both varus and valgus elbow alignment; after 6 mm of radial shortening, the distal ulnar force averaged 92.4% (in varus alignment) and 60.9% (in valgus alignment). Equal distal load-sharing between the radius and ulna occurred after approximately 5 mm of radial shortening with the elbow in valgus alignment and after approximately 2 mm of radial shortening with the elbow in varus alignment. In valgus alignment, the force in the interosseous membrane was negligible after all degrees of radial shortening; in varus alignment, the mean force in the interosseous membrane decreased from 51.2% (0 mm of distal radial shortening) to 0% (6 mm of distal radial shortening) because of progressive slackening of the interosseous membrane. CONCLUSIONS: Radial head excision shifted the applied wrist force that normally would be transmitted to the elbow, through radial head-capitellar contact, to the interosseous membrane. The resulting proximal radial displacement created an ulnar-positive wrist and increased distal ulnar loading. Radial shortening and ulnar lengthening procedures have been designed to shift the applied wrist force from the distal part of the radius to the distal part of the ulna; it is commonly assumed that these procedures have equivalent biomechanical effects. We found that radial shortening resulted in slackening of the interosseous membrane, thereby negating its ability to transmit load through the forearm. Slackening of the interosseous membrane would not be expected with distal ulnar lengthening procedures. CLINICAL RELEVANCE: When the radial head has been fractured or excised, the mechanical status of the interosseous membrane is critical to the load-sharing process. If the interosseous membrane remains intact, distal ulnar loads will be limited to less than half of the applied wrist force; if the interosseous membrane has been damaged, nearly the entire applied wrist force will be shifted to the ulna. The amount of radial shortening or ulnar lengthening performed at the time of surgery during joint-leveling procedures has been largely empirical. We found that distal ulnar load increased by approximately 10% for each millimeter of radial shortening.

Aged↗