Abduction forces in the one-legged stance"
TL;DR: The forces acting in the abductor muscles and on the head of the femur have been determined experimentally for three subjects in a range of different pelvis attitudes.
About: This article is published in Journal of Biomechanics.The article was published on 1970-03-01. It has received 271 citations till now.
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TL;DR: In one hip in the first patient and in the second patient the direction of large forces approximated the average anteversion of the natural femur, so the joint loading was observed over the first 30 and 18 months, respectively, following implantation.
1,243 citations
01 Jan 1987
TL;DR: In this article, the authors discuss congenital dysplasia and dislocation of the hip in children and adults, and the authors propose a method to find knowledge and lesson everywhere you want.
Abstract: Many people are trying to be smarter every day. How's about you? There are many ways to evoke this case you can find knowledge and lesson everywhere you want. However, it will involve you to get what call as the preferred thing. When you need this kind of sources, the following book can be a great choice. congenital dysplasia and dislocation of the hip in children and adults is the PDF of the book.
769 citations
TL;DR: An automated system utilizing an electronic digitizer and computer software was used to analyze cross-sectional geometric properties of 11 femoral and tibial locations in 119 individuals from the Pecos Pueblo, New Mexico site, allowing identification of clear differences in geometric properties between different regions of the femur and tibia.
Abstract: Variation in long bone cross-sectional geometry can be given a more precise functional interpretation using engineering beam theory. However, difficulties in measurement technique have generally prevented studies of large samples of cross sections in this way. In the present study, an automated system utilizing an electronic digitizer and computer software was used to analyze cross-sectional geometric properties of 11 femoral and tibial locations in 119 individuals from the Pecos Pueblo, New Mexico site. The data generated allow identification of clear differences in geometric properties between different regions of the femur and tibia. These differences appear to be related to specific in-vivo mechanical loadings of the lower limb bones, serving to reduce stress and strain under these loadings. The data are also used to investigate possible differences in loading of the femur and tibia in the Pecos and modern samples, and between humans and a nonhuman primate sample.
527 citations
TL;DR: The prediction of muscle load sharing and the corresponding hip, knee and ankle joint reactions during walking when the motion pattern is known beforehand shows excellent agreement with typical electromyographic patterns for all the major muscles.
507 citations
Cites background from "Abduction forces in the one-legged ..."
...Morrison (1970). firm the phasic activity of the plantar flexors (the calf group, tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus and peroneus brevis) which are active during the middle and latter parts of the stance phase and, therefore indirectly assist in…...
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TL;DR: Several experimental techniques, including geometric measurement, tendon-joint displacement measurement and direct load measurement, are available for the determination of orientation and moment arms of the muscles about a joint.
Abstract: In muscle force analysis, orientations and moment arms of the muscles about a joint provide essential coefficients in the equilibrium equations. For the determination of these parameters, several experimental techniques, including geometric measurement, tendon-joint displacement measurement and direct load measurement, are available. Advantages and disadvantages associated with each of the techniques are reviewed and compared based on our extensive experience.
359 citations
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Journal Article•
TL;DR: The study of the forces acting in and around the hip joint explains numerous, apparently unrelated, clinical observations.
Abstract: The study of the forces acting in and around the hip joint explains numerous, apparently unrelated, clinical observations.
The reacting force in the head of the femur resists not merely the pressure of the superincumbent body weight, but, in addition, the force of the abductor muscles and the tension on the iliotibial tract which is necessary to hold the pelvis in equilibrium. This latter force exceeds the weight of the body by a ratio of from 1.4:1 to 1.9:1. The minimum static pressure on the head of the femur is approximately 2.4 to 2.6 times the body weight.
Normally this force is not borne vertically, but at an angle of approximately 165 to 170 degrees from the vertical and in line with the medial trabeculae of the femoral neck. This static force remains constant in direction, irrespective of whether the pelvis is levated or depressed on the non-weight-bearing side.
With the knowledge of the direction of the reacting force through the head and neck of the femur against the pelvis, the changing angle of the capital epiphysis during growth becomes partially explicable. Close inspection of roentgenograms of the upper end of the femur in individuals of various ages reveals that the epiphyseal line always lies at a right angle to the direction of the medial trabeculae of the femoral neck (Fig.9). Since the reacting force in the femur follows these trabeculae, there is no sheer on the epiphyseal cartilage. The only force to which it is subjected normally is a compressional one. As growth occurs, with increasing length of the femoral neck and increasing angle of pull of the abductor muscles and the fascia, the epiphyseal cartilaginous plate rotates so as to lie perpendicular to the equilibrant force in the femoral neck.
The interrelationship of these forces becomes altered in cases of paralysis of the abductor muscles and in congenital dislocation of the hip. In the first instance, the loss of muscle power prevents the attainment of equilibrium with the body in a normal position. To prevent the pelvis from rotating toward the non-weight-bearing side, the individual shifts his center of gravity over the affected hip by bending to that side. The resultant forces, acting through the hip, become more nearly vertical. The equilibrant or reacting force in the femoral neck likewise shifts toward the vertical; the epiphyseal cartilaginous plate, remaining perpendicular to these forces, continues to be relatively horizontal; and coxa valga results. This is a constant finding in individuals who have had paralysis early in life, and the degree of coxa valga is in proportion to the loss of muscle power.
Coxa valga occurs in individuals suffering from congenital dislocation of the hip, for the same factors are at work. In these cases, the loss of fulcrum prevents the normal development of the abducting forces. The load is borne vertically on the femur, and the capital epiphysis reacts by remaining horizontal.
[see pdf for figure]
The so-called "antalgic" gait of the individual who has a painful disease of the hip joint is of interest. On the surface,it appears rather peculiar that a patient with a painful hip will walk by throwing himself over the painful joint, giving rise to a gait which may be compared with that of a glutaeus medius weakness. By so doing, however, the individual shifts his center of gravity over the hip, thus decreasing the required pull of the abductor muscles. This, in turn, decreases the pressure upon the femoral head from a force of 2.4 to 2.6 times the body weight to simply the superincumbent body weight. This expediency of gait, while decreasing the total load on the femoral head, results in a change in the direction of the reacting force in the femur. Instead of the body weight being borne at an angle which thrusts the head into the acetabulum, the load is carried vertically upon the femur. This alteration in direction of the forces causes changes in the femoral head, which are depicted in the roentgenograms. In malum coxae senilis, the bone changes affect predominantly the superior aspect of the femoral head, because the forces are concentrated there. In epiphysiolysis the assumption of an antalgic gait, while leading to a decrease in the total load on the femur, causes that load to be borne vertically, with the result that a sheer is applied to the epiphyseal plate, which normally is not present. This sheer will facilitate further slipping.
The importance of the abductor muscles and the iliotibial tract in altering the direction of the reacting forces in the femoral neck should be emphasized. Any surgical approach to the hip joint which injures these structures and weakens the forces exerted by them will not only modify the magnitude, but also the direction, of the reacting force through the femoral neck.
279 citations
24 citations
"Abduction forces in the one-legged ..." refers background in this paper
...This is substantially confirmed by Charnley and Pusso (1968), who show that during the stance phase of slow walking the vertical floor reaction is constant for a period....
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