Journal of orthopaedic research : official publication of the Orthopaedic Research Society
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Angular deformities were created in cadaver forearms at proximal, middle, and distal third levels of the radius and ulna separately, and at middle and distal third levels of both bones, to determine the corresponding limitations of pronation and supination. The ranges of pronation and supination were recorded using a rotational motion measurement apparatus instrumented with a 360 degrees goniometer. ⋯ With cadaver forearms, on the average, angulation of 10 degrees of the radius or ulna in coronal or sagittal planes limited pronation and supination by less than 24 degrees, whereas angulation of 10 degrees of both the radius and the ulna limited pronation and supination by less than 18%. Comparison of experimental results with clinical findings showed that, despite the errors involved in measuring forearm deformities in patients using biplanar radiographs, the experimental results predicted the clinical loss of pronation and supination to within 17% for the fractures of the radius, and within 8% accuracy for the fractures of the ulna.
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Fresh human cadaveric specimens of occiput (C0) to C3 were subjected to axial torque. The resulting physiological motions were studied in an unconstrained three-dimensional manner. Effects of sequential transections of the left and right alar ligaments on the relative motions of C0-C1 and C1-C2 were studied. ⋯ In general, neutral zones showed greater increases, e.g., 3.9 degrees to each side at the C1-C2 joint. Comparing right and left axial rotations, after transection of the left alar ligament, showed greater percentage increases for the right, as compared to the left, axial rotation, at both C0-C1 and C1-C2 joints. Functional loss of the alar ligaments indicates a potential for rotatory instability, which, however, must be determined in conjunction with other clinical findings, such as neurological dysfunction, pain, and deformity.
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To test the hypothesis that appropriate and timely neuromuscular control of limb motions plays an important role in the preservation of joint health, we kinematically and kinetically examined the behavior of the legs of young adult subjects at heel strike during natural walking. We compared a group of 18 volunteers, who, we presumed, were preosteoarthrotic because of mild, intermittent, activity-related knee joint pain, with 14 age-matched asymptomatic normal subjects. The two groups of subjects exhibited similar gait patterns with equivalent cadences, walking speeds, terminal stance phase knee flexion, maximum (peak) swing angular velocity, and overall shape of the vertical ground reaction. ⋯ The follow-through of the leg immediately after heel strike was more violent with larger peak axial and angular accelerations of the leg echoed by a more rapid rise of the ground reaction force. This sequence of events represents repetitive impulsive loading, which consistently provoked osteoarthrosis in animal experiments. We refer to this micro-incoordination of neuromuscular control not visible to the naked eye as "microklutziness."
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Nonhuman primate (monkey) bites to researchers and attending animal care staff may present problems in patient management. Such inoculations can transmit serious bacterial and viral infections to the human handlers. ⋯ Since Herpesvirus simiae (B virus) is enzootic in Asiatic monkeys of the genus Macaca, and since B virus infection in humans is usually fatal, additional prophylactic and therapeutic measures must be taken when persons are bitten by macaque monkeys. Primate bites require early aggressive intervention.
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The variation in the dimensions of the lumbar spinal canal under both flexion-extension and axial compression-distraction was studied using computerized tomography (CT) scans in human cadaver lumbar spine specimens. In 3-mm-thick CT slices through the disk at L3-L4, the cross-sectional area of the spinal canal was reduced by around 40 mm2, corresponding to a 16% reduction of the initial area when the lumbar spines were moved both from flexion to extension and from distraction to compression. ⋯ During these motions, the ligamentum flavum did not appear to be a significant factor for the dynamic changes affecting the dimensions of the canal. This held true even after the disk had been excised in order to produce a total collapse of the disk space.