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Planar Motion

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The planar motion of the two adjacent body segments can be described by the concept of the instant center of motion. As one body segment rotates about the other, at any instant, there is a point that does not move. This point has zero velocity and acts as a center of rotation. This technique yields a description of motion at one point only and is not applicable if motion of 15 degree or greater exists in other planes. When the instantaneous center of rotation is at the contact point between femur and tibia, the instantaneous velocity is zero and the tibia is rolling around the femoral surface. An understanding of the motion between the articulating surfaces of the knee joint is important for understanding causes of wear, instability and loosening …show more content…

KNEE JOINT STABILITY The muscles, ligaments, menisci, osseous geometry and joint capsule all combine in a complex manner to produce joint stability. If any of these structures malfunction or disrupted, knee joint instability occurs. These factors are all interdependent and serve the function of both determining normal motion and limiting motion beyond a certain point. JOINT SURFACE The constraints provided by the femoral and tibial joint surfaces are not adequate for functional stability. The distal femur is convex, where as the proximal tibia is partially flat, medially slightly concave and convex laterally. However, the tibial intercondylar eminence and the articular geometry added some potential for stability. Hsieh and Walker concluded that geometric conformity of the condyles was the most important criteria to decrease laxity under load bearing. They also came to the conclusion that, to perform anterior or posterior, rotatory and medial or lateral movements, the femur must glide upward on the tibial curvature. Similarly, to rotate the femur "screws out", giving an upward movement. Medial/lateral motion produces this effect to an even greater degree because of the tibial spines. This is called the "uphill principle". These authors concluded that under low loading conditions, the soft structures (ligaments, capsule and meniscus) provided joint stability and whenever there is increase in the load; the conformity of femoral condylar surface becomes the most important factor for joint

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In healthy individuals, anterior rotation of the innominate occurs during extension of the freely swinging leg. When the innominate anteriorly rotates, it glides inferiorly down the short arm and posteriorly along the long arm of the SIJ. In non-weights bearing an arthrokinematic glide between the innominate and the sacrum occurs during posterior rotation of the innominate and is physiological (i.e., follows the articular surfaces). In weight bearing, the close-packing of the SIJ precludes this physiological glide. Sacral nutation produces the same relative arthrokinematic glide as posterior rotation of the innominate (inferoposterior motion of the sacrum is the same as anterosuperior motion of the innominate); sacral counternutation produces the same arthrokinematic glide as anterior rotation of the innominate (anterosuperior motion of the sacrum is the same as inferoposterior motion of the

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Task 8.1b- disorders and dysfunctions of the musculoskeletal system Osteoarthritis Osteoarthritis is the most common arthritis. It is an incurable condition which affects your joints. The surface within the joints become joints become damaged which stops the joints moving smoothly. [1] The symptoms of this are: o Pain and stiffness o Swelling o Not being able to move the joint normally o A grating/grinding feeling

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994 Words | 4 Pages

With this, the medical cruciate ligament functions to stabilize the knee against lateral or valgus forces.

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whether or now not you lead a bodily energetic subculture, a sedentary one, or someplace in between, you might frequently understand how important it is that your knees be functioning comfortably and be soreness free. The knees absolutely serve plenty of capabilities. Not completely do these endure the load of the physique; the knees are additionally essential for almost any movement. As such, it comes as no surprise that knee joint agony is a typical predicament, experienced by means of contributors of all a while, sizes, and origins. What motives Knee Joint ache?

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Introduction The aim of this review paper is to access the anterior cruciate ligament (ACL) injury of the knee (tibiofemoral) joint, which is a common sport and exercise injury related to the musculoskeletal system. Investigation of the anatomy and physiology of the knee joint, and the diagnosis, etiology, pathophysiology, treatment, rehabilitation and prevention of ACL injuries will provide a descriptive epidemiology. This will aid readers in making informed management and treatment decisions, and guide them to safely perform movements to prevent injury. This review paper will incorporate holistic views on relevant scientific research, including primary resources such as journal articles and lecture notes, which will be cross-referenced

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1299 Words | 6 Pages

Including the knee osteoarthritis can affect all the joints in our body, the most commonly affected joints are found in the neck and back, the hips, hands as well as the metacarpals. Osteoarthritis targets the cartilage within our joints causing them to deter. A cartilage is a unique tissue with compressive properties that are imparted by its extracellular matrix. An extracellular matrix is a combination of secreted molecules that self assemble into an

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The knee joint is one of the strongest and most important joints in the human body. It allows the lower leg to move relative to the thigh while supporting the body’s weight (Taylor, n.d.) as knee joint is one of the major weights bearing joint in the body. Knee joint plays an important role in our daily lives such as walking, running, sitting and standing. It allows physiological movement such as flexion and extension.

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Inflammation or damage to the muscular tissues hooked up to the joint can create issues throughout the movement, infected tendons mainly as a result of tendinitis or swelling of brusaes due to trochanteric bursitis may also purpose slight to severe joint ache within the hip. Osteonecrosis can also be one of the vital fashioned explanations for hip joint ache which happens when there is inadequate blood supply to any part of the skeletal structure of the joint. The other motives for hip joint discomfort are muscle pulls, and fractures either instantly of the bones worried within the joint or to the femur and stress fractures which occur as a result of over use of the joint particularly through athletes or sportspersons. Many varieties of arthritis may motive hip anguish as they are able to infect tissues and muscle tissue and also damage the brusaes to preclude smooth motion of femur in the acetabulum and of muscle groups and

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IMAGE 177 IMAGE 178 Tight hip rotator muscles pull on the leg so it falls to the outside, sometimes evenly and sometimes not. The primary function of the psoas muscle is to flex the hip, but it is an accessory muscle, also, for hip external rotation. When the legs fall out into external rotation while the patient is in supine, you can be sure

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In contrast, when apes walk bipedal, it is energetically costly, but they compensate by stretching out their arms and leaning their trunk towards the supported side. The gluteal muscles on the supported side are able to balance the trunk by pulling up the unsupported side of the pelvis. Clearly, the pelvic changes helped facilitate efficient bipedalism in modern

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645 Words | 3 Pages

The medial longitudinal arch height increases by this cable-like action without any direct muscular function (Valmassy, 1996; Hicks, 1954). This mechanism provides rigidity for the push-off phase and stability to the medial longitudinal arch (Reid, 1992). Collapsing of the medial longitudinal arch leads to calcaneal pronation with associated forefoot abduction and commonly causes foot problems such as HAV by increasing the force distribution through the medial rays (Stovitz and Coetzee,

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However, the mismatch of prosthesis can cause some severe complication to patient and bring some negative impact to patient. Most of the arthroplasty knee is involved in the middle age group but nowadays

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2142 Words | 9 Pages

Human running is often viewed as a bouncing motion where ones legs act similar to a spring. The stiffness one experiences in their legs “spring” helps to determine the centre of mass (COM) mechanics of the body (McGowan et al., 2012). In stance phase of the gait cycle, ones leg swings through an arc during running and so the angle at which this swing takes place, the force at which ones foot makes contact with the ground as well as the stiffness in the leg are all components that help determine the COM and the ground reaction forces experienced by the individual (McGowan et al., 2012). The tests showed that leg stiffness for people without prostheses seemed to remain constant or increase with speed. People with prostheses stiffness in the legs decreased.

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During the Mandatory period, which lasted until May 1948, “the social, political, and economic structure for the future state of Israel was developed. Two factors were instrumental in fostering the rapid economic growth of the Jewish sector: immigration and capital inflows” (Halevi, 2008). However, the major stages in the historical development of ancient Israel are historically known for the narratives in the Hebrew Bible and the Old Testament. “Israel” was named after the Hebrew patriarch Jacob during his encounter with the Angel of God at the river Jabbok (Genesis 32:28). “Israel developed into a kingdom under the leadership of King David, who consolidated the various tribes under his ruling.

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