Influência da espessura do osso cortical sobre a velocidade de propaga？？o do ultrassom

objective: an experimental in vitro study was carried out to evaluate the influence of cortical bone thickness on ultrasound propagation velocity. methods: sixty bone plates were used, made from bovine femurs, with thickness ranging from 1 to 6 mm (10 of each). the ultrasound velocity measurements were performed using a device specially designed for this purpose, in an underwater acoustic tank and with direct contact using contact gel. the transducers were positioned in two ways: on opposite sides, with the bone between them, for the transverse measurement; and parallel to each other, on the same side of the bone plates, for the axial measurements. results: in the axial transmission mode, the ultrasound velocity speed increased with cortical bone thickness, regardless of the distance between the transducers, up to a thickness of 5 mm, then remained constant thereafter. there were no changes in velocity when the transverse measures were made. conclusion: ultrasound velocity increased with cortical bone thickness in the axial transmission mode, until the thickness surpasses the wavelength, after which point it remained constant. level of evidence: experimental study.