The Physical Properties of the Cortical Neck of the Femur

Interest in the proximal end of the femur with regard to its mechanical value as a weight-bearing system has been the subject of conjecture for many years in terms of its geometric arrangement of trabeculae, following the descriptions of Bourgery (1832) and the theories of Ward (1838), Culmann (1866), and Meyer (1867).Analysis of the forces acting upon the head and neck of femur under normal physiological conditions has been reported by many authors, and has been reviewed recently by Rydell (1966).Since the magnitude and directions of these forces are not well known, it is difficult to understand them from a mechanical point of view.Stresses and strains in the femoral neck, when loaded, have been quantitatively analysed by means of the stress coat technique (Kiinfscher 1935, Evans, Lissner & Pedersen 1948, 1949, 1956), the photoelastic model (Pauwels 1948, 1955, Kummer 1966) and strain gauges (Hirsch & Frankel 1960, 1961).In the laboratory the mechanical forces acting on this extremity with various types of loading and the reaction of the femoral neck to them have been studied under specific experimental conditions in the past (Hirsch & Brodetti 1956) and, more recently, under vital conditions (Hirsch & Rydell 1964, Rydell 1966).Although the physical properties of most of the human compact bones have been studied by several authors, studies on human cortical bone of the neck of femur have been restricted to studies by Sedlin & Hirsch (1966) who reported a few physical properties on the inferior portion of the cortical neck of the femur.Since it is generally accepted that the stress distribution in the bone is dependent upon the structure