|
|
The effect of the growth and development of the endosteal surface on the estimation of cross-sectional properties
Königová, Viktória ; Sládek, Vladimír (advisor) ; Friedl, Lukáš (referee)
Past studies concerning deriving periosteal and endosteal contours from micro-CT scans of non-adult long bones found the greatest error to stem from the automatic processing of the endosteal contours. Furthermore, with increasing age, a decrease in the estimation error of the cross-sectional properties was observed. This study aims to identify the specific source of the estimation error and to optimize the use of the automatic method of deriving endosteal contours. Four parameters (circularity, solidity, roundness, and aspect ratio) were used to quantify the shape properties of the endosteal contour. These parameters were tested on 91 individuals from birth to early adulthood. As for the ontogenic changes in the endosteal contour, a continuous decrease in the jaggedness of the endosteal contour had been observed, mainly based on the changes in the circularity. Circularity was chosen as the parameter upon which the criteria of use of the automatic method of deriving the endosteal contour was based. The criterium is based on the prediction of whether the customary threshold of 5 % percent prediction error would be surpassed while using the automatic method at a certain level of circularity. Applying the criteria of the minimum threshold of circularity (0,83 for MA, 0,71 for CA, and 0,7 for ZP) will...
|
|
|
Sexual dimorphism in tibial loading during human locomotion
Dvořáková, Barbora ; Hora, Martin (advisor) ; Friedl, Lukáš (referee)
Locomotion is one of the most important qualities of man and has always been associated with survival, foraging ans subsistence. During the course of evolution, men and women developed some form of gender specialization which resulted in different level of mobility between the sexes. Throughout history, the types of subsistence have changed and the degree of sedentism has increased. However, despite all the changes in subsistence, gender specialization and bone robusticity sexual dimorphism in the robusticity of the lower limb bones remained surprisingly stable. Is it possible that women load lower limb bones differenty than men (e.i. due to different body proportions)? The aim of this work is to determine wheter there is sexual dimorphism between the sexes of the recent living population in the cross-sectional properties of the tibia and in the load on the tibia during running. In this work we used images of the tibia from magnetic resonance imaging and kinematic and kinetic data during the run of 20 probands. By using musculoskeletal modeling we estimated the bending moment acting at 50 % of the tibial length as well as the angle of action of this moment. After adjusting for size, no significant difference was found in the results of cross-sectional geometry of the bone in any of the monitored...
|
guest ::
