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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A biomechanical analysis of the role of the crural fascia in the cat hindlimb

Stahl, Victoria Ann 07 July 2010 (has links)
The potential of the crural fascia to increase the articulation of the posterior thigh muscles through the in series connection of the structures, suggests that the crural fascia may influence the endpoint force direction of the muscles by partially redirecting the muscular force output. Furthermore, not only the in series connections should be considered but also how the parallel alignment of the crural fascia and the triceps surae may influence the force direction from the muscles. A redirection in force may, in turn, affect the intra-limb coordination or contribute to the selection of a task variable muscle activation pattern. The central objective was to evaluate the role of the synergistically located, posterior, distal musculature and connective tissue during locomotion. The central hypothesis was that the crural fascia would redirect the force output from the posterior thigh muscles to the endpoint and consequently increase propulsion within the limb. We selected to perform our studies in the spontaneously locomoting decerebrate cat, which allows us to investigate acute treatments applied to the hindlimb. The overall objective was accomplished by: (1) evaluating the role of the crural fascia during level walking; (2) determine the acute effect of denervating the triceps surae muscles and disrupting the crural fascia during level walking; and (3) evaluating the change in force direction output of selective stimulation of muscles in different limb configurations before and after complete fasciotomy. Our findings demonstrated that the crural fascia not only assists in propulsion but also acts to stabilize the distal limb. Furthermore, the acute denervation of the triceps surae resulted in a decrease in leg length and an increase in ankle yield during the weight acceptance phase of stance. This suggests that the conservation of the limb length as a task level variable is an adaptation rather than an immediate response.
2

Ankle Morphology: Interface of Genetics, Ontogeny and Use

Turley, Kevin 03 October 2013 (has links)
A central concept in Evolutionary theory is the character trait. It provides a context in which to explore differences and similarities among taxa, both extant and extinct. It is expanded in scope in Evolutionary Developmental theory to functional units with a biological role, "evolutionarily stable configurations." The talo-crural joint is such a configuration, a highly canalized structural unit in primates forming the interface between organism, and foot and substrate. It is a microcosm in which to examine the relationship of shape with environment and function and the interplay of genetics, ontogeny, and use. Geometric Morphometric analysis of landmark data was employed in studying the articular surfaces of the talus in a diverse sample of adult specimens in nine catarrhine taxa. The influence of four factors on talar shape was examined: superfamily, a proxy for phylogeny; size and mass, a proxy for physical attributes; and substrate preference, a proxy for behavior. All significantly affected shape, and substrate preference was unrelated to the others. Appositional articular morphology, the shape of the subchondral bone surfaces of the talo-crural joints in an expanded sample of 12 taxa, showed a significant effect of the four proxies on the tibial and talar components, and substrate preference was weakly related to the other proxies in each. Singular Warp analysis of the cross-covariance matrices of the joints demonstrated sorting of taxa by substrate use and signals of convergent and divergent evolution among hominoids and cercopithecoids in joint shape. The ontogeny of the appositional articular shape was examined using adult and subadult specimens grouped by molar eruption. Singular Warp analysis demonstrated a genetic signal in the subadults, strongest in the slowly maturing African hominoids, and an epigenetic signal across taxa to substrate use in the adults. The talo-crural joint, a highly canalized, modular, and integrated "evolutionarily stable configuration," provides a model for the study of the evolution of shape. The epigenetic signal observed is consistent with plasticity or developmental plasticity in response to the interaction of the joint complex with the environment due to a behavioral effect, substrate use. This dissertation included previously unpublished, co-authored material.
3

Bránice v roli zevního jícnového svěrače - spirometricko-manometrická studie / Diaphragm in the role of external esophageal sphincter - spirometric - manometric study

Veličková, Barbora January 2015 (has links)
The aim of this thesis is to present a complex information about the etiology, diagnosis and treatment of gastroesophageal reflux disease (GERD) and to further elucidate the function of the diaphragm as the external esophageal sphincter and as a part of the antireflux barrier in patients with GERD. The study included 87 patients with verified GERD. Patients were subjected to a set of postural and respiratory maneuvers - caudal position of chest, abdominal breathing and measuring of the maximal respiratory pressures, all performed on the basis of tolerance to position and maneuver. The high-resolution manometry (HRM) was chosen to record the changes in pressure in the lower esophageal sphincter and for the measurement of respiratory pressures was used the spirometric system MasterScope. It was found that postural and respiratory maneuvers, that activate the diaphragm, increase the pressure in the EGJ. The most significant increase occurred during the maximal inspiratory maneuver, which increased LES pressure up to 261.2 %. The results also show that patients with GERD have reduced the strength of respiratory muscles, especially inspirational muscles. Reaching only 66.5 % of predicted PImax. We have demonstrated that patients with GERD have significantly lower diaphragm muscle strength, what...
4

Sledování aktivity dolního jícnového svěrače u zdravých jedinců v různých posturálních pozicích / Activity of lower oesophageal sphincter in healthy patients in various postural positions

Beranová, Kateřina January 2018 (has links)
The aim of this thesis is to describe information about GERD, its etiology, anatomy, pathology, treatment options and rehabilitation in patients with GERD. Lower oesophageal sphincter and antireflux barrier. The study was approved by the ethics committee. 30 probands were included in the study and their health status was verified using the Health Related Quality of Life questionnaire. A manometric catheter was inserted, proband was instructed to maintain various postural positions. Lying supine with lower limbs elevated above the surface, lying supine with lower limbs elevated above the surface with head fixated manualy, sitting and standing position, load in the center of gravity 3/6/9 kg, load outside the center of gravity 3/6/9 kg, lifting of the office chair. It has been shown that LES pressure increases in all postural positions compared to resting pressure. The positions activate the diaphragm to demonstrate the postural function of the diaphragm. The most significant change in LES pressures was in the postural position of lying supine with lower limbs elevated above the surface, the LES resting pressure of 20.34mmHg changed to the pressure of LES 40.92mmHg. Clinical experience and studies have shown that patients with GERD have disposition for respiratory and / or vertebrogenic difficulties....

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