The compressive properties of single osteons

Abstract

The compressive strength of single human osteons has been investigated in specially prepared samples using a microtesting machine equipped with a microwave micrometer. The main conclusions which can be drawn from our results are: (1) In agreement with Gebhardt's theories the ultimate compressive strength is greatest for osteons having transversally oriented fiber bundles, lowest for osteons having longitudinally oriented fiber bundles, and intermediate for osteons whose fiber bundles change direction in successive lamellae through a n angle of about 90". Nearly 60 years ago the German investigator W. Gebhardt ('06) developed a theory designed to explain the relationship between structure and mechanical properties of osteons. As no suitable technique for performing investigations on isolated osteons was then available, Gebhardt founded his theory on macroscopic metallic models in which bone collagen and crystallites were represented by steel wires.During the last few years we have carried out a series of investigations on the tensile properties of single osteons (Ascenzi and Bonucci, '64, '65, '67; Ascenzi, Bonucci and Checcucci, '66). As it was practically impossible to isolate a whole osteon, the studies in tensile strength were done using portions of longitudinally sectioned units. For this purpose the dissection technique described by Ascenzi and Fabry ('59) was applied. The apparatus used for measuring the variations in length of the osteons subjected to tensile stress was a microwave extensimeter based on cavity and pulse techniques. This apparatus was developed at the Physics Institute of the University of Pisa by Gozzini and co-workers (see Battaglia, Bruin and Gozzini, '58).Recently further attempts have been made by us to test the compressive properties of cylindrical samples corresponding approximately to the middle portion of single osteons. The aim of this report is to present the results of these investigations. MATERIAL AND METHODPreparation and selection of samples. The osteon, when fully formed, is an irregularly cylindrical and branching structure a few millimeters in length and usually oriented in the long axis of the bone.

Circularly polarized light standards for investigations of collagen fiber orientation in bone

“…The hypothesis that collagen fibers of preferred orientation and distribution have biomechanical significance was first set forth by Gebhardt (1905) and later tested by Ascenzi and Bonucci (1964, 1967, 1968 and Simkin and Robin (1974). These authors provided evidence that collagen fibers and mineral crystallites in a predominantly transverse orientation, perpendicular to the long axis of the bone, are better able to resist compressive forces, whereas longitudinal fibers and crystallites, oriented more parallel to the long axis of the bone, are better able to resist tensile forces.…”

Course of Fracture Line in Sagittal Splitting of Human Mandible

“…Morphological studies based on 3-dimensional visualization were previously carried out using the familiar conventional tracing paper 7,8) and sketching technique by superimposing rubber sheets. In recent years, a significant amount of information has become available from the use of 3-dimensional image reconstruction surgery with computer graphics, a technique widely used in a range of different fields 1,4,9) . The system used in this study employed the surface rendering technique.…”

Experimental validation of finite element predicted bone strain in the human metatarsal

“…Studies performed on single osteons show that transversely-oriented collagen fibres increase the compressive strength and modulus of the bone, while longitudinally-oriented fibres increase the tensile strength and modulus (85)(86)(87). The cross-link density in the collagen fibres also affect the mechanical properties of the bone.…”