Estudi comparat i funcional de la regió lumbar humana i d' altres primats
- Autores: Elías Valverde Llor
- Directores de la Tesis: A. Casinos (dir. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2010
- Idioma: español
- Tribunal Calificador de la Tesis: Jacinto Nadal Puigdefábregas (presid.), Jorge Cubo García (secret.), Françoise - Kyou Jouffroy (voc.)
- Materias:
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- Resumen
The lumbar region of the primates, including human being, was investigated from different points of views. Some research was carried out on the human lumbar region only. Using X-ray absorptiometry, the following variables were measured: average length and width, length-width ratio, posterior projected surface area and bone mineral density. The sample included almost 2,000 humans ranging from new born to 21-year-old individuals. The first analysis of these variables was the regression of each one of them against body mass and height of the individuals, using the power equation, and considering both sexes separately. Differences between males and females were found regarding either the exponent of the equation or the y-interception. A second analysis consisted in the study of the growth trajectories of the different variables using the Gompertz model. Complementarily, the ontogenetic variation of the bone shape was also analysed using a derived Gompertz function that took account for the relative contribution of endochondral and periosteal ossifications. The general aim was to detect and differentiate possible heterochronic processes linked to sex. In all cases, values obtained for females were significantly higher than those obtained for males. Comparing with previous studies on other parts of the human skeleton, it was ascertained that patterns were similar, although the growth rate of the lumbar region was slower than those of other skeletal elements. Sexual differences in growth rate accounted for only a small proportion of the variation of most of the variables. Human being lumbar region was compared with that of other primates studying the ventrodorsal and craniocaudal orientations of the transverse processes of the lumbar vertebrae in simians. This study permitted an indirect estimation of both the extensors and flexors muscles acting on the lumbar joint L2-L3. Results obtained shown important differences between hominins. A parallel study was carried out about the scaling of the anterior and posterior flat articular surfaces of the different lumbar vertebral bodies in catarrhines. From these surfaces, axial and bending strengths were estimated. Again an important variability within catarrhines and hominins in particular was observed. Differences between cercopithecids and hominids were also observed.
