[INTRODUCING AN APPARATUS FOR MEASURING POSTURAL ANGLE].

STUDY DESIGN: This study compared the reliability of 3 techniques used to measure alignment between the occiput and cervical spine. OBJECTIVES: Intraobserver and interobserver intraclass correlation coefficient were computed to determine the most reliable method to measure occipitocervical angle. SUMMARY OF BACKGROUND DATA: No studies have been performed comparing occipitocervical angle measurement techniques. METHODS: The angles between the inferior endplate of second cervical vertebrae and the occiput line using the Chamberlain line, McRae line, and McGregor line were measured from lateral cervical radiographs of 30 healthy volunteers. Five spine surgeons made measurements. RESULTS: Mean intraobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.0 degrees (ranging from 0 degrees-15 degrees), 4.7 degrees (from 0 degrees-28 degrees), and 1.5 degrees (from 0 degrees-9 degrees), respectively; intraobserver intraclass correlation coefficients of the angles were 0.956, 0.835, and 0.975. Mean interobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.3 degrees (from 0.4 degrees-6.4 degrees), 5.0 degrees (from 1.8 degrees-11.9 degrees), and 1.4 degrees (from 0 degrees-4.5 degrees), respectively; interobserver intraclass correlation coefficients were 0.939, 0.802, and 0.972. The highest reliability indexes were obtained for McGregor line. CONCLUSIONS: The McGregor line is the most reproducible and reliable method for measurement of the occipitocervical angle.

Anthropometry↗

PubMed2004

Total body water measurements using resonant cavity perturbation techniques.

A recent paper proposed a novel technique for determining the total body water (TBW) of patients suffering with abnormal hydration levels, using a resonant cavity perturbation method. Current techniques to measure TBW are limited by resolution and technical constraints. However, this new method involves measuring the dielectric properties of the body, by placing a subject in a large cavity resonator and measuring the subsequent change in its resonant frequency, fres and its Q-factor. Utilizing the relationship that water content correlates to these dielectric properties, it has been shown that the measured response of these parameters enables determination of TBW. Results are presented for a preliminary study using data estimated from anthropometric measurements, where volunteers were asked to lie and stand in an electromagnetic screened room, before and after drinking between 1 and 2 l of water, and in some cases, after voiding the bladder. Notable changes in the parameters were observed; fres showed a negative shift and Q was reduced. Preliminary calibration curves using estimated values of water content have been developed from these results, showing that for each subject the measured resonant frequency is a linear function of TBW. Because the gradients of these calibration curves correlate to the mass-to-height-ratio of the volunteers, it has proved that a system in which TBW can be unequivocally obtained is possible. Measured values of TBW have been determined using this new pilot-technique, and the values obtained correlate well with theoretical values of body water (r = 0.87) and resolution is very good (750 ml). The results obtained are measurable, repeatable and statistically significant. This leads to confidence in the integrity of the proposed technique.

Anthropometry↗