Constructional peculiarities of the human tibia defined by reference to ultrasound measurement data

The distribution of the acoustic properties of the human tibia was studied by the method of ultrasound probing. This enabled the determination of some constructional peculiarities of the tibia. A considerable non-uniformity of ultrasound propagation velocity has been revealed along the entire length of the bone. The uniform velocity fields were longitudinally orientated in the diaphysis whereas in the epiphyseal parts of the bone they had a cross-sectional orientation. Isorapid zones formed spiral structures positioned at an angle of 6.7 +/- 0.5 degrees to the bone axis. Moreover, right-wound spiral was characteristic of the left bone but left-wound spiral of the right. A new parameter--acoustic stiffness of the construction is suggested. In the proximal third of the bone its acoustic stiffness was more pronounced in the sagittal plane; in the middle part it was best defined in the direction of the angular zones of the bone, but in the distal part it had a clearly marked frontal orientation. A statistically valid distinction of ultrasound velocity in the cross-sectional and longitudinal zones of separate bones has been established in all the bones studied.