[Studies on the biomechanics of the human clavicle (author's transl)]

Abstract

64 non preserved and 35 preserved clavicles were fractured in three defined positions in a bending test by a tension testing machine with electronic measurement of force. 30 non preserved bones were fractured in an axial infraction test. Force-deflection-diagrams were registered, and the values of maximum load, breaking load, ultimate deflection and energy were correlated to cross section and thickness of compacta. The significantly greater non preserved male clavicles are loadable at a higher level (medium breaking load about 1200 N) than female bones (medium breaking load abut 800 N). The breaking energy of the more flexible female clavicles is about 30% lower than those of males whereas elastic modulus of female clavicles is significant greater. Preservation has a significant influence on biomechanical properties of bones: ultimate deflection decreases; breaking energy, ultimate stress and elastic modulus increase. Breaking load is greatest in the middle portion of the clavicle, while deflection is greatest in the sternal portion. Removal of periosteum causes lower breaking load, deflection, ultimate stress and elastic modulus as well. With axial load clavicle fractures occur most frequently between middle and sternal third.