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Knee joints
Diagram of human knee
Latin articulatio genus
Gray's subject #93 339
Nerve femoral, obturator, sciatic
MeSH Knee
Dorlands/Elsevier a_64/12161228
For other uses, see Knee (disambiguation). Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Introduction ( Joints or Articulations Sutural ligament Fibrocartilages A nerve is an enclosed cable-like bundle of peripheral Axons (the long slender projections of Neurons. The femoral nerve, the largest branch of the Lumbar plexus, arises from the dorsal divisions of the second third and fourth Lumbar nerves. The obturator nerve arises from the ventral divisions of the second third and fourth Lumbar nerves; the branch from the third is the largest while that from the second is The sciatic nerve (also known as the ischiatic nerve) is a large Nerve that starts in the lower back and runs through the buttock and down the Lower limb Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group

The knee is the lower extremity joint connecting the femur, fibula, patella, and the tibia. A joint is the location at which two or more Bones make contact The femur is the thigh bone In Humans, it is the longest, most voluminous and strongest Bone. The patella or kneecap is a thick triangular Bone which articulates with the Femur and covers and protects the knee joint The tibia, shinbone, or shankbone is the larger and stronger of the two Bones in the Leg below the Knee in vertebrates and connects [1] Since in humans the knee supports nearly the entire weight of the body, it is the joint most vulnerable both to acute injury and the development of osteoarthritis. Osteoarthritis ( OA, also known as degenerative Arthritis, degenerative joint disease) is a clinical syndrome in which low-grade inflammation

Contents

Human anatomy

Upon birth, a baby will not have a conventional knee cap, but a growth formed of cartilage. In human females this turns to a normal bone knee cap by the age of 3, in males the age of 5.


The knee is a complex, compound, condyloid variety of a synovial joint which hovers. Synovial joints (or diarthroses, or diarthroidal joints) are the most common and most moveable type of Joints in the human body It actually comprises two separate joints.

The recess behind the knee is called the popliteal fossa. The popliteal fossa is a space or shallow depression located at the back of the Knee-joint. It can also be called a "knee pit. "

Ligaments

Name Capsule From To Description
anterior cruciate ligament (ACL) inside lateral condyle of femur anterior intercondylar area The critically important ACL prevents the tibia from being pushed too far anterior relative to the femur. The anterior cruciate ligament (or ACL) is one of the four major Ligaments of the Knee. The lateral condyle is one of the two projections on the Lower extremity of femur. The anterior intercondyloid fossa (or intercondylar area) is the location where the Anterior cruciate ligament attaches to the Tibia. It is often torn during twisting or bending of the knee.
posterior cruciate ligament (PCL) inside medial condyle of femur posterior intercondylar area Injury to this ligament is uncommon but can occur as a direct result of forced trauma to the ligament. The posterior cruciate ligament (or PCL is one of the four major Ligaments of the Knee. The medial condyle is one of the two projections on the Lower extremity of femur. Posteriorly the Medial condyle and Lateral condyle are separated from each other by a shallow depression the posterior intercondyloid fossa (or intercondylar This ligament prevents posterior displacement of the tibia relative to the femur.
capsular ligament - - - -
patellar ligament outside patella tuberosity of the tibia - Also occasionally called the patellar tendon because there is no definite separation between the quadriceps tendon (which surrounds the patella) and the area connecting the patella to the tibia. An articular capsule (or joint capsule) is an envelope surrounding a Synovial joint. The patellar ligament ( anterior ligament) is the central portion of the common tendon of the Quadriceps femoris, which is continued from the Patella to The patella or kneecap is a thick triangular Bone which articulates with the Femur and covers and protects the knee joint Narrow below where the anterior surfaces of the condyles of the Tibia end in a large oblong elevation the tuberosity of the tibia, which gives attachment to the Ligamentum In Human anatomy, the quadriceps tendon connects the quadriceps femoris muscles to the superior aspects of the Patella on the anterior of the thigh This very strong ligament helps give the patella its mechanical leverage and also functions as a cap for the condyles of the femur. The femur is the thigh bone In Humans, it is the longest, most voluminous and strongest Bone.
medial collateral ligament (MCL a. The medial collateral ligament of the Knee is one of the four major Ligaments of the knee k. a. "tibial") outside medial epicondyle of the femur medial tibial condyle The MCL protects the medial side of the knee from being bent open by a stress applied to the lateral side of the knee (a valgus force). The medial epicondyle of the Femur is a large convex eminence to which the Tibial collateral ligament of the Knee-joint is attached The medial condyle is the medial portion of the Upper extremity of tibia. In Orthopedics, a valgus deformity is a term for the outward angulation of the distal segment of a bone or joint
lateral collateral ligament (LCL a. The Fibular Collateral Ligament ( external lateral or long external lateral ligament) is a strong rounded fibrous cord attached above to the back part of the k. a. "fibular") outside lateral epicondyle of the femur head of fibula The LCL protects the lateral side from an inside bending force (a varus force). The lateral epicondyle of the Femur, smaller and less prominent than the medial epicondyle, gives attachment to the Fibular collateral ligament of the The upper extremity or head of the Fibula is of an irregular quadrate form presenting above a flattened articular surface directed upward forward and medialward for articulation In Orthopedics, a varus deformity is a term for the inward angulation of the distal segment of a bone or joint
oblique popliteal ligament outside medial condyle of tibia - Tendinous expansion of the semimembranosus muscle. The oblique popliteal ligament ( posterior ligament) is a broad flat fibrous band formed of fasciculi separated from one another by apertures for the passage of vessels and The medial condyle is the medial portion of the Upper extremity of tibia. Strengthens the back of the capsule
arcuate popliteal ligament outside Intercondylar area of tibia, and lateral condyle of femur, to below head of fibula Connects to the medial portion of the fibular head -This ligament strengthes the knee posterolaterally and usually when injured is in combination with a PCL and popliteus tendon injury. The arcuate popliteal ligament is an extracapsular ligament of the Knee. The lateral condyle is one of the two projections on the Lower extremity of femur. For other uses see Fibula (disambiguation The fibula or calf bone is a Bone located on the lateral side of the Tibia

Menisci

These are cartilaginous elements within the knee joint which serve to protect the ends of the bones from rubbing on each other and to effectively deepen the tibial sockets into which the femur attaches. They also play a role in shock absorption. There are two menisci in each knee, the medial meniscus and the lateral meniscus. This article is about the parts in the human kneeFor other uses of the term meniscus see Meniscus and lens (optics. The medial meniscus is a Fibrocartilage band that spans the medial Knee, and lies on the head of the Tibia. The lateral meniscus, also called the external semilunar fibrocartilage, is a Fibrocartilaginous band that spans the lateral side of the interior of the Knee Either or both may be cracked, or torn, when the knee is forcefully rotated and/or bent.

Movements

The knee permits the following movements: flexion, extension, as well as slight medial and lateral rotation. In Anatomy, flexion is a position that is made possible by the joint angle decreasing Also, the knee has special locking and unlocking mechanisms, related to movement by the femoral condyles on the tibial plateau. The ligaments and menisci, along with the muscles which traverse the joint, prevent movement beyond the knee's intended range of motion. This article is about the parts in the human kneeFor other uses of the term meniscus see Meniscus and lens (optics. It is also classified as a hinge joint.

The range of movement is as follows: Flexion is permitted up to 120º when the hip is extended, 140º when the hip is flexed and 160º when the knee is flexed passively. Medial rotation is limited to 10º and lateral rotation to 30º .

Blood supply

The femoral artery and the popliteal artery help form the arterial network surrounding the knee joint (articular rete). There are 6 main branches:

The medial genicular arteries penetrate the knee joint

Injury

Model demonstrating parts of an artificial knee
Model demonstrating parts of an artificial knee

In sports that place great pressure on the knees, especially with twisting forces, it is common to tear one or more ligaments or cartilages. An increasingly common victim to injury is the anterior cruciate ligament, often torn as a result of a rapid direction change while running or some other, violent twisting motion. It can also be torn by extending the knee forcefully beyond its normal range. In some such cases, other structures incur damage as well. Especially debilitating is the unfortunately common "unhappy triad" of torn medial collateral and anterior cruciate ligaments and a torn medial meniscus. An unhappy triad (or terrible triad, or O'Donoghue's triad) is an injury to the Knee. This typically arises from a combination of inwards forcing and twisting.

Before the advent of arthroscopy and arthroscopic surgery, patients having surgery for a torn ACL required at least nine months of rehabilitation. Arthroscopy (also called arthroscopic surgery) is a Minimally invasive surgical procedure in which an examination and sometimes treatment of damage of the Arthroscopy (also called arthroscopic surgery) is a Minimally invasive surgical procedure in which an examination and sometimes treatment of damage of the With current techniques, such patients may be walking without crutches in two weeks, and playing some sports in but a few months. Anterior cruciate ligament reconstruction ( ACL reconstruction) is a surgical tissue graft replacement of the Anterior cruciate ligament, In Australian rules football, knee injuries are among the most common, especially in ruck contests, involving the crashing of two knees during the leap. Australian (rules football, or simply known as football, footy or Aussie rules, is a Team sport played between two teams of 18 players In Australian rules football, a ruckman is generally a tall and athletic player who contests at centre bounces and stoppages (such as boundary throw-ins and ball-ups These injuries forced new rule changes for the 2005 season.

In addition to developing new surgical procedures, ongoing research is looking into underlying problems which may increase the likelihood of an athlete suffering a severe knee injury. These findings may lead to effective preventive measures, especially in female athletes, who have been shown to be especially vulnerable to ACL tears from relatively minor trauma. Techniques to minimize the risk of an ACL injury while skiing are published by Vermont Safety Research

Diagnosis

Several diagnostic maneuvers help clinicians diagnose an injured ACL. In the anterior drawer test, the examiner applies an anterior force on the proximal tibia with the knee in 90 degrees of flexion. The anterior drawer test for anterior cruciate ligament laxity is one of many medical tests used to determine the integrity of the Anterior cruciate ligament. The Lachman test is similar, but performed with the knee in only about twenty degrees of flexion, while the pivot-shift test adds a valgus (outside-in) force to the knee while it is moved from flexion to extension. A Lachman test is a medical test used for examining the Anterior Cruciate Ligament (ACL in the Knee for patients where there is a suspicion of a torn ACL In Anatomy, flexion is a position that is made possible by the joint angle decreasing Lateral Pivot Shift Test for Anterolateral Knee Instability This test can be use to look at the anterolateral structures’ of the Knee and look for Sprains of Any abnormal motion in these maneuvers suggests a tear.

The diagnosis is usually confirmed by MRI, the availability of which has greatly lessened the number of purely diagnostic arthroscopies performed. Arthroscopy (also called arthroscopic surgery) is a Minimally invasive surgical procedure in which an examination and sometimes treatment of damage of the


Animal anatomy

In humans the knee refers to the joints between the femur, tibia and patella. In quadrupeds, particularly horses and ungulates the term is commonly used to refer to the carpus, probably because of its similar hinge or ginglymus action. Ungulates (meaning roughly "being Hoofed quot or "hoofed animal" are several groups of Mammals most of which use the tips of their toes usually In Tetrapods the carpus is the sole cluster of the Bones in the Wrist between the radius and Ulna and the Metacarpus In the hinge joint ( ginglymus) the articular surfaces are moulded to each other in such a manner as to permit motion only in one plane forward and backward the extent of motion The joints between the femur, tibia and patella are known as the stifle in quadrupeds. The stifle joint is a complex joint in the Hindlimbs of Quadruped Mammals such as the Sheep, Horse or Dog. In insects and other animals the term knee is used widely to refer to any ginglymus joint.

See also

Additional images

Knee MR

Knee MR

Knee X-ray

Cruciate ligaments

Female knee

Male knee

Left knee-joint from behind, showing interior ligaments. Cartilage is a type of dense Connective tissue. It is composed of specialized cells called chondrocytes that produce a large amount of extracellular matrix Articular cartilage, most notably that which is found in the knee joint is generally characterized by very low friction high wear resistance and poor regenerative qualities The knee examination, in Medicine, is performed as part of a Physical examination, or when a patient presents with Knee Pain or a history that A leglock is a Joint lock that is directed at Joints of the leg such as the Ankle, Knee or Hip joint. A reflex hammer is a medical instrument used by physicians to test deep Tendon Reflexes Testing for reflexes is an important part of the neurological physical Unicompartmental knee arthroplasty is a Surgical procedure used to relieve Arthritis in one of the Knee compartments in which the damaged parts of the knee

Capsule of right knee-joint (distended). Lateral aspect.

References

  1. ^ eMedicine/Stedman Medical Dictionary Lookup!. Retrieved on 2008-01-15. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 588 BC - Nebuchadrezzar II of Babylon lays siege to Jerusalem under Zedekiah 's reign

Dictionary

knee

-noun

  1. In humans, the joint in the middle part of the leg.
  2. (anatomy) The joint, or region of the joint, between the thigh and leg.
  3. (anatomy) In the horse and allied animals, the carpal joint, corresponding to the wrist in humans.
  4. (shipbuilding) A piece of timber or metal formed with an angle somewhat in the shape of the human knee when bent.
  5. (archaic)An act of kneeling, especially to show respect or courtesy.
  6. Any knee-shaped item or sharp angle in a line, "the knee of a graph", an inflection point
  7. A blow made with the knee; a kneeing

-verb

  1. (transitive, archaic) to kneel to
  2. (transitive) poke or strike with the knee
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