OCLC: 53820178
PROQUEST: 305293639
The purpose of this work is to verify and modify, if necessary, the neck response characteristics of the current child crash test dummies using m agnetic resonance imaging and muscle physiology. The child crash test dum m y neck response is scaled from the responses of adult necks using the neck circum ference ratio (child to adult) as a means for adjustment. This method of scaling relies heavily on external body anthropom etry and contains certain assumptions about the internal anatom ies and muscle physiology. The response scaling laws em ployed are derived from geom etric and dynamic similitude and are a widely accepted method for m odeling system behavior using a scale model. However, the model is required to possess geom etric similarity and hom ogeneity. In the case of the child neck, it is plausible tha t certain anatom ies do not scale according to the external body dimensions. Even though the neck volume m ay scale nicely with the neck circum ference, the distribution of the bony anatom ies and musculature may scale quite differently.
The child neck response scaling relies on neck circum ference, which is easy to measure and linear in the characteristic dimensions (neck depth and breadth). This scaling was conducted before the wide availability of whole body scanning techniques. Therefore, the relevant internal anatom ies have never been evaluated for consistency with the anthropom etric neck response scaling.
An integral part of the neck response scaling includes an assumption regarding the physiologic potential of the muscle tissues themselves. The ability of the muscle to produce force for a given cross-section (physiologic muscle stress) is considered not to vary with age. The study will address this issue as well. In all three key areas are investigated:
These three areas will be assessed using methods that rely on magnetic resonance im aging for accurate measurements of internal body anatomies. Volunteers range in age from neonate to sixty-four years of age.