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Biomedical subjects

R Tarr

Publications and source records attributed to R Tarr.

5 recordsLinked to original sources
PubMed1992

Angular deformities and forearm function.

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. These experimental results were compared to data obtained from clinical and radiographic examination of 105 patients with similar residual deformities following treatment of fractures by nonsurgical means, to evaluate the accuracy of the experimental model and to determine if loss of rotational motion could be predicted based on radiographic findings. 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.

Cadaver↗
PubMed1986

Plain film evaluation of patients with abdominal pain: are three radiographs necessary?

Current recommendations for the plain radiographic evaluation of abdominal pain suggest a minimum three-film series including an erect and supine abdominal view and an erect chest study. Three film radiographic abdominal "series" were obtained in 252 consecutive emergency-room patients who presented with abdominal pain. The views were analyzed independently for their relative diagnostic value. Radiologic pathologic findings were present in 20% of the abdominal films and in 13% of the chest radiographs. The supine abdominal view and the erect chest study diagnosed normality or abnormality in 98% of these patients. The elimination of the erect abdominal view from the routine abdominal series could result in financial savings, decreased radiation exposure, and a more efficient use of technician time, without significant loss of diagnostic information.

Abdomen, Acute↗
PubMed1978

Dislocations after total hip-replacement arthroplasties.

In a series of 300 total hip replacements, nine (3 per cent) dislocated. Precise measurements of the orientation of the acetabular cup were made and it was found that anterior dislocations were associated with increased acetabular-component anteversion. There was no significant correlation between cup-orientation angle and posterior dislocation. The dislocation rate for cup orientation with anteversion of 15 +/- 10 degrees and lateral opening of 40 +/- 10 degrees was 1.5 per cent, while outside this "safe" range the dislocation rate was 6.1 per cent. Other factors that were documented include time after surgery (with the greatest risk in the first thirty days) and surgical history (with a greater risk in hips that have had prior surgery).

Adult↗
PubMedDate not supplied

Measurements of thermal properties for human femora.

In this study, density, specific heat, thermal conductivity, and thermal diffusivity were measured experimentally along the lengths of human cadaveric femora. Fresh and dry bone samples were selected from both male and female specimens, and for different age groups varying between 44 and 73 years old. Measured values for specific heat vary between 1.14 and 2.37 J/gm degrees C; for thermal conductivities the range is from 0.16 to 0.34 W/m degrees C; and for thermal diffusivities the range is from 0.10 to 0.23 cm2/sec, depending on whether the bone samples were fresh or dry, cancellous or cortical. The experimental results are presented in non-dimensional coordinates and are compared with the few other data available in the literature.

Adult↗