Compensation for interaction torques during single- and multijoint limb movement.
(25/1127)
During multijoint limb movements such as reaching, rotational forces arise at one joint due to the motions of limb segments about other joints. We report the results of three experiments in which we assessed the extent to which control signals to muscles are adjusted to counteract these "interaction torques." Human subjects performed single- and multijoint pointing movements involving shoulder and elbow motion, and movement parameters related to the magnitude and direction of interaction torques were manipulated systematically. We examined electromyographic (EMG) activity of shoulder and elbow muscles and, specifically, the relationship between EMG activity and joint interaction torque. A first set of experiments examined single-joint movements. During both single-joint elbow (experiment 1) and shoulder (experiment 2) movements, phasic EMG activity was observed in muscles spanning the stationary joint (shoulder muscles in experiment 1 and elbow muscles in experiment 2). This muscle activity preceded movement and varied in amplitude with the magnitude of upcoming interaction torque (the load resulting from motion of the nonstationary limb segment). In a third experiment, subjects performed multijoint movements involving simultaneous motion at the shoulder and elbow. Movement amplitude and velocity at one joint were held constant, while the direction of movement about the other joint was varied. When the direction of elbow motion was varied (flexion vs. extension) and shoulder kinematics were held constant, EMG activity in shoulder muscles varied depending on the direction of elbow motion (and hence the sign of the interaction torque arising at the shoulder). Similarly, EMG activity in elbow muscles varied depending on the direction of shoulder motion for movements in which elbow kinematics were held constant. The results from all three experiments support the idea that central control signals to muscles are adjusted, in a predictive manner, to compensate for interaction torques-loads arising at one joint that depend on motion about other joints. (+info)
The morphometry of the coracoid process - its aetiologic role in subcoracoid impingement syndrome.
(26/1127)
Anatomical morphometric studies of the coracoid process and coraco-glenoid space were carried out on 204 dry scapulae. No statistically significant correlations were found between length, or thickness of the coracoid process, prominence of the coracoid tip, coracoid slope, coraco-glenoid distance, or position of the coracoid tip with respect to the uppermost point of the glenoid. These anatomical characteristics were independent of the dimensions of the scapulae. Three configurations of the coraco-glenoid space were identified. Type I configuration was found in 45% of scapulae and Type II and Type III, in 34% and 21% of specimens, respectively. The lowest value of the coraco-glenoid distance were seen in Type I scapulae. Morphometric characteristics which might predispose to subcoracoid impingement were found in 4% of Type I scapulae. A total of 27 scapulae, nine with each type of configuration were submitted to CT scanning. Scapulae with a Type I configuration were found to have low values for the coraco-glenoid angle and coracoid overlap, which are known to be associated with a short coraco-humeral distance. Subjects with a Type I configuration, and severe narrowing of the coraco-glenoid space, appear to be predisposed to coraco-humeral impingement. These morphometric characteristics may be easily evaluated on CT scans. (+info)
Sequelae of sarin toxicity at one and three years after exposure in Matsumoto, Japan.
(27/1127)
In order to clarify the later sequelae of sarin poisoning that occurred in Matsumoto City, Japan, on June 27, 1994, a cohort study was conducted on all persons (2052 Japanese people) inhabiting an area 1050 meters from north to south and 850 meters from east to west with the sarin release site in the center. Respondents numbered 1237 and 836 people when surveys were conducted at one and three years after the sarin incident, respectively. Numbers of persons with symptoms of sarin toxicity were compared between sarin victims and non-victims. Of the respondents, 58 and 46 people had symptoms associated with sarin such as fatigue, asthenia, shoulder stiffness, asthenopia and blurred vision at both points of the survey, respectively. The prevalences were low; some complained of insomnia, had bad dreams, difficulty in smoking, husky voice, slight fever and palpitation. The victims who had symptoms one year after the incident had a lower erythrocyte cholinesterase activity than did those who did not have symptoms at the early stage; such persons lived in an area with a 500 meter long axis north east from the sarin release site. The three-year cohort study clearly showed that the odds ratios of almost all of the symptoms were high in the sarin-exposed group, suggesting a positive relationship between symptoms and grades of exposure to sarin. These results suggest that symptoms reported by many victims of the sarin incident are thought to be sequelae related to sarin exposure. (+info)
The Southampton examination schedule for the diagnosis of musculoskeletal disorders of the upper limb.
(28/1127)
OBJECTIVES: Following a consensus statement from a multidisciplinary UK workshop, a structured examination schedule was developed for the diagnosis and classification of musculoskeletal disorders of the upper limb. The aim of this study was to test the repeatability and the validity of the newly developed schedule in a hospital setting. METHOD: 43 consecutive referrals to a soft tissue rheumatism clinic (group 1) and 45 subjects with one of a list of specific upper limb disorders (including shoulder capsulitis, rotator cuff tendinitis, lateral epicondylitis and tenosynovitis) (group 2), were recruited from hospital rheumatology and orthopaedic outpatient clinics. All 88 subjects were examined by a research nurse (blinded to diagnosis), and everyone from group 1 was independently examined by a rheumatologist. Between observer agreement was assessed among subjects from group 1 by calculating Cohen's kappa for dichotomous physical signs, and mean differences with limits of agreement for measured ranges of joint movement. To assess the validity of the examination, a pre-defined algorithm was applied to the nurse's examination findings in patients from both groups, and the sensitivity and specificity of the derived diagnoses were determined in comparison with the clinic's independent diagnosis as the reference standard. RESULTS: The between observer repeatability of physical signs varied from good to excellent, with kappa coefficients of 0.66 to 1.00 for most categorical observations, and mean absolute differences of 1.4 degrees -11.9 degrees for measurements of shoulder movement. The sensitivity of the schedule in comparison with the reference standard varied between diagnoses from 58%-100%, while the specificities ranged from 84%-100%. The nurse and the clinic physician generally agreed in their diagnoses, but in the presence of shoulder capsulitis the nurse usually also diagnosed shoulder tendinitis, whereas the clinic physician did not. CONCLUSION: The new examination protocol is repeatable and gives acceptable diagnostic accuracy in a hospital setting. Examination can feasibly be delegated to a trained nurse, and the protocol has the benefit of face and construct validity as well as consensus backing. Its performance in the community, where disease is less clear cut, merits separate evaluation, and further refinement is needed to discriminate between discrete pathologies at the shoulder. (+info)
Relation of glenohumeral and acromioclavicular joint destruction in rheumatoid shoulder. A 15 year follow up study.
(29/1127)
OBJECTIVES: To evaluate the relation of glenohumeral (GH) and acromioclavicular (AC) joint involvement in a cohort of 74 patients with seropositive and erosive rheumatoid arthritis (RA) followed up prospectively. METHODS: At the 15 year follow up radiographs of 148 shoulders were evaluated, and the grade of destruction of GH and AC joints were assessed by the Larsen method. One GH joint arthroplasty had been performed after 13 years of the disease onset and the preoperative radiograph was evaluated. RESULTS: Erosive involvement (Larsen grade >/= 2) was observed in 96 of 148 (65%) of the shoulders. Both GH and AC joints were affected in 62 of 148 (42%) shoulders. GH joint alone was involved in nine (6%) shoulders and only AC joint was affected in 25 (17%) shoulders. AC joint destruction correlated with the GH joint destruction, r=0.74 (95% confidence intervals (CI) 0.65 to 0.80 ). CONCLUSION: In RA AC joint is affected more often than the GH joint, but in half of the patients both joints are involved. This should be remembered when treating painful rheumatoid shoulder. (+info)
Isokinetic performance and shoulder mobility in elite volleyball athletes from the United Kingdom.
(30/1127)
OBJECTIVES: To evaluate the differences in strength and mobility of shoulder rotator muscles in the dominant and non-dominant shoulders of elite volleyball players. METHODS: Isokinetic muscle strength tests were performed at speeds of 60 and 120 degrees/s, and shoulder mobility was examined in ten players from the England national men's volleyball squad. The subjects also completed a questionnaire that included a visual prompt and analogue pain scale. RESULTS: The range of motion of internal rotation on the dominant side was less than that on the non-dominant side (p < 0.01). The average peak strength at 60 degrees/s external eccentric contraction was lower than that of internal concentric contraction in the dominant arm, but was higher in the non-dominant arm. Six of the ten subjects reported a shoulder problem, described as a diffuse pain located laterally on the dominant shoulder. CONCLUSIONS: These elite volleyball players had a lower range of motion (internal rotation) and relative muscle imbalance in the dominant compared with the non-dominant shoulder. (+info)
Synovial chondromatosis of the subcoracoid bursa.
(31/1127)
Synovial chondromatosis, is the chondroid metaplasia of the synovial membrane. Large joints such as the knee and hip are most commonly involved. Extraarticular involvement is rarely described. Synovial chondromatosis may be associated with impingement syndrome of the shoulder. We report a case of synovial chondromatosis of the subcoracoid bursa, which resulted in impingement symptoms. (+info)
Radiographic joint space in rheumatoid glenohumeral joints. A 15-year prospective follow-up study in 74 patients.
(32/1127)
OBJECTIVE: To evaluate radiographically the glenohumeral (GH) joint space in patients with long-term rheumatoid arthritis (RA). METHODS: A cohort of 74 patients with RA were followed prospectively for 15 yr. At the end point, 148 shoulders were radiographed using a standard method. The GH joint space was examined from the radiographs using a method developed previously for population studies; the joint space was measured at three different sites and the average of the three measurements, the integral space, was calculated. Destruction of the GH joints was assessed with the Larsen method on a scale of 0-5 and compared with the joint space measurements. RESULTS: The mean GH joint space in RA patients was 3. 1 (S.D. 3.3), range -17.3 to 5.7 mm; 2.7 mm (S.D. 4.5) in men and 3. 2 mm (S.D. 2.8) in women. The mean of the affected joints (Larsen grades 2-5), 1.7 mm (S.D. 4.5), was notably narrower than the mean 4. 4 mm (S.D. 0.6) of the non-affected (Larsen grades 0-1) joints. Pathological GH joint space, less than 2 mm, was found in five (15%) of 36 joints in men and in 14 (13%) of 112 joints in women. All the joints graded as Larsen 4 and 5 (n = 17) fulfilled this pathological criterion. Joint space narrowing was associated [r = - 0.66, 95% confidence interval (CI): -0.56 to -0.75] with increasing destruction (Larsen grading) of the joint. The narrowing was significant between non- (Larsen 0, 1), moderately (Larsen 2, 3) and severely (Larsen 4, 5) affected joints (P < 0.001). However, a remarkable step in this process occurred between Larsen grades 3 and 4 when the mean joint space diminished from 3.1 to 0.3 mm. CONCLUSIONS: Joint space narrowing is a frequent consequence of GH joint rheumatoid affection. However, joint space narrowing is a late phenomenon occurring not until after marked erosive destruction, which should be noted when using the Larsen method for GH joints. (+info)