Abstract: An intramedullary nail for the fixation of bone fractures is formed of two slidably engaging elongate members. One of the members includes an articulated channel which serves to bend the other member to form an expanding end region within the bone cavity to achieve fixation therein.

Abstract: The present invention relates to an improved expandable intramedullary nail for the fixation of bone fractures. The nail includes an elongate sleeve having one end adapted to be inserted within the medullary cavity of the bone. The one end of the sleeve is formed of a predetermined maximum retracted diameter to permit the insertion of the one end within the bone cavity. A plurality of circumferentially spaced, radially expandable elements are carried by the one end of the sleeve. The elements are radially movable from a first, retracted position wherein the elements define a first diameter to a second, expanded position wherein the elements define a second diameter greater than the predetermined maximum retracted diameter and the first diameter. In accordance with the present invention, when the elements are in the expanded position, the elements provide at least two support points at the second diameter and axially spaced along the sleeve for engagement with the inner wall of the bone cavity.

Abstract: The present invention relates to an instrument for measuring the range of angular displacement associated with two human body portions connected to a common joint. The instrument includes two pivotally connected, elongate rods, and separate supports for supporting each of the rods on a respective one of the body portions in spaced relationship with the body portion. Each of the supports includes a pair of ball and socket assemblies which are mounted on the respective body portions in spaced relation to one another. The ball of each ball and socket assembly has an aperture formed therethrough for receiving the associated elongate rod. Such a support arrangement enables the body portions to be rotated about the common joint without affecting the natural movements of the body portions. An encoder is utilized to pivotally connect the two elongate rods and to generate an electrical output signal representing the relative angular position between the two rods.

Abstract: An appropriately shaped cavity, formed in a cut femoral bone shaft, is provided with a barrier or plug in its distal portion so that a cement in its liquid state may be injected into the cavity under pressure for causing the cement to flow into the small interstices of the bone forming the cavity.A preferred method of inserting the plug at a predetermined depth in the cavity generally includes the steps of: (1) forming and retaining the plug in a die; (2) inserting the die containing the plug into the cavity to the predetermined depth; (3) releasing the plug from the die; and (4) injecting the liquid cement under pressure into the plugged cavity.The device for placing the plug at the predetermined depth in the cavity generally comprises the die, an elongated body member, appropriately shaped so as to be inserted into the cavity and to which the die is detachably connectable, and a pusher member contained within the body member for releasing the plug from the die.

Abstract: A method for optically determining the ratio of Poisson's ratio to modulus of elasticity for optically isotropic and optically anisotropic transparent materials and then for determining the stress-optical constants for such materials. A collimated monochromatic light beam is directed at the tip of a crack in a loaded thin plate specimen of the material and the diameters of the resulting transmitted and reflected caustics are measured at points equidistant from the specimen. The light beam also is directed to an uncracked region in a loaded thin plate specimen of the material and the number of displaced fringe reflected on a screen are counted for a predetermined change in loading. The ratio of Poisson's ratio to modulus of elasticity and the stress-optical constants are determined from the thickness of the specimen, the displaced fringe count, the wavelength of the light beam and the ratio of the caustic diameters.

Abstract: A method for optically determining the stress-optical constants of optically isotropic and anisotropic materials. A collimated beam of monochromatic light is directed at the tip of a crack in a thin plate specimen under plane-stress from a direction substantially perpendicular to the surface of the specimen and to the direction of the stress. Reflected and transmitted stress-optical constants are determined from a ratio of the diameters of transmitted and reflected caustics from the specimen and the known Poisson's ratio and modulus of elasticity for the specimen.