No / Chest radiography is one of the most commonly performed radiographic examinations worldwide. Routinely acquired in the erect posteroanterior (PA) position, a chest radiograph displays substantial amounts of medical information when accurate patient positioning is achieved. However, a rotated PA chest radiograph has reduced diagnostic quality and appearances may mask or mimic chest pathology. Radiographic assessment of patient rotation around the sagittal plane has traditionally been undertaken by assessing the distance between the medial end of the clavicles and a line drawn through the spinous processes at the level of the clavicles. This approach continues to be advocated in radiographic technique textbooks internationally although no identified author has provided criteria to determine when a rotated PA chest radiograph should be repeated; determined the relationship between perceived clavicle to spinous process distance and actual degree of patient rotation; or considered the impact of body morphology, in particular the anteroposterior thoracic diameter, on radiographic appearances of rotation. Objectives To determine the impact of anteroposterior chest diameter on radiographic appearances of sagittal rotation on PA chest radiographs. Design Experimental study. Methods and Settings Sixty computed tomography thorax examinations, stratified for gender, were reviewed and data aggregated to determine average anteroposterior (AP) thoracic dimensions. A bespoke experimental unit was constructed specifically to enable testing of the impact of sagittal rotation on radiographic appearances. The experimental unit was situated within a calibrated circular frame enabling 360° rotation at 1° intervals around a central rotational point. The experimental unit components were varied in 1 cm intervals from 9 cm to 15 cm around the central rotation point to reflect varying AP chest diameters. At each interval, images were acquired at 0, 2, 5, 7, 10, and 15° sagittal rotation using a horizontal central ray, consistent centring point, and a source-image distance of 180 cm. Results A clear linear relationship between AP thoracic diameter and the radiographic appearances of sagittal rotation was noted. Considering significant rotation to be when the medial end of clavicle overlaps the spinous process on the radiographic image, this appearance occurred at a much smaller degree of rotation on wide AP thoracic diameters (15 cm, 5°) than narrower AP thoracic diameters (9 cm, 10°). Conclusions The routine application of the distance between the medial end of the clavicles and a line drawn through the spinous processes at the level of the clavicles as a method of assessing degree of sagittal rotation, diagnostic image quality, and need for repeat is flawed. Persistence in the application of this approach without cognisance of the impact of body morphology on radiographic appearances will result in persons with large AP thoracic diameters being more likely to have a PA chest radiograph repeated for a specified degree of rotation than persons with smaller AP thoracic diameters.

This thesis focuses on the relationship between body image and somatotypes in the young Czech student population. Previous studies have shown a relationship between body image and BMI, notwithstanding, somatotypes describe body morphology in a more detailed way. Somatotypes describe the amount of body fat (endomorphy), the amount of muscle mass and the robustness of bones (mesomorphy), and the length of arms and legs relative to the rest of the body (ectomorphy). Seventy-one women and seventy men participated in our study. They completed a battery of questionnaires (The Multidimensional Body-Self Relations Questionnaire; The Body Figure Scale of Dosedlová et al., 2008; Rosengerg's self-esteem scale; State-Trait Anxiety Inventory - T; and Beck's Depression Inventory - II). Then they underwent an anthropometric measure of somatotype components (endomorphy, mesomorphy, and ectomorphy) according to Carter and Heath's anthropometric method and were assigned to a certain somatotype. In our sample, there were 5 somatotypes in men (endomorph, mesomorph, ectomorphic mesomorph, mesomorph-ectomorph and ectomorph) and 6 somatotypes in women (endomorph, endomorph- mesomoroph, mesomorph, mesomorph-ectomorph, ectomorph and the central type). The questionnaires' scores were then statistically compared between...

Three studies were performed to examine biophysical sources of individual variability in the thermoregulatory responses to exercise, and the influence of skin blood flow on heat loss potential during severe heat stress. Study 1 investigated whether unbiased comparisons of changes in rectal temperature (ΔTre) should be compared at a fixed absolute rate of heat production (Hprod; W) or a fixed Hprod per unit mass (W/kg), and whether local sweat rates (LSR) should be compared at a fixed evaporative requirement for heat balance (Ereq; W) or a fixed Ereq per unit of surface area (W/m2), between independent groups of unequal body mass and body surface area (BSA). Study 2 examined whether individual variation in ΔTre, whole-body sweat loss (WBSL), and steady-state LSR is best explained by biophysical factors related to Hprod, Ereq, and body size, and if factors related to aerobic fitness (VO2max) and body fatness correlate with the residual variance in these responses. Study 3 tested whether alterations in skin blood flow shift the critical vapour pressure (Pcrit) above which core temperature could no longer be regulated in hot/humid conditions, indicating altered heat loss potential from the skin. In study 1, exercise at fixed absolute Hprod and Ereq resulted in greater ΔTre and LSR in smaller individuals (smaller mass and BSA), but exercise at set Hprod in W/kg and Ereq in W/m2 resulted in no differences in ΔTre and LSR, respectively, regardless of body size and %VO2max. In study 2, 50-71% of the individual variation in ΔTre, whole-body sweat loss (WBSL), and steady-state LSR was explained by Hprod (W/kg), absolute Ereq (W) and Ereq (W/m2) respectively, while body fat percentage and %VO2max contributed merely 1-4% to the total variability. In study 3, despite a ~20% lower skin blood flow, Pcrit was unaffected by a large reduction in skin blood flow following iso-smotic dehydration, with no differences in core and skin temperatures and sweating observed. Collectively, these findings suggest that between-group comparisons and modelling of thermoregulatory responses must first consider biophysical factors related to metabolic heat production and body size, rather than factors related to VO2max and body fatness. Furthermore, lower levels of skin blood flow may not impair maximum heat dissipation from the skin to the external environment during severe passive heat stress as previously thought.