Knee Joint

the movable connection of the femur with the tibia of the crus and the kneecap, or patella, in man and most terrestrial vertebrates.

The principal movements in the knee joint are flexion and extension of the crus. In man, the knee joint is formed by the condyles of the femur, the superior articular surface of the tibia, and the articular surface of the patella. The intercondylar eminence is located between the external and internal condyles of the tibia. The curvature of the articular surfaces of the condyles of the femur does not correspond in radius to the curvature of the articular surface of the tibia. This noncorrespondence, or incongruence, is to some extent equalized by two crescent-shaped cartilaginous formations called the menisci, which are thickened along their peripheries. The flat inferior surfaces of the menisci face the superior articular surface of the tibia, and the concave superior surfaces face the condyles of the femur. The inner edges of the menisci are attached by thick ligaments to the intercondylar eminence; the thickened outer edges are fused with the inner synovial membrane of the bursa. Anteriorly, the menisci are joined to one another by the transverse ligament of the knee. Thus, the ends of the menisci are fixed. However, their bodies remain capable of shifting, which makes minor rotational movements possible when the knee is bent.

The principal ligaments of the knee joint are the cruciform, which cross each other from the external and internal condyles of the femur and attach to, in front of, and behind the intercondylar eminence. The bursa is fortified anteriorly by three broad bands, which are formed by ligamental fascicles of the quadriceps muscle of the femur. As though woven into the middle band is the patella, which covers the knee joint anteriorly. Laterally, the bursa is fortified by the internal, or medial, ligament of the tibia and the external, or lateral, ligament of the fibula. These ligaments prevent lateral movement and rotation of the crus when the extremity is extended. The posterior surface of the bursa is fortified by the tendons of the muscles of the crus and thigh, which are interwoven in it. The synovial membrane that covers the articular capsule internally lines the articulated surfaces and the cruciform ligaments, forming several pockets (involutions and bursae), of which the largest is located behind the tendons of the quadriceps muscle. These synovial bursae, which are located at the points of attachment of the muscles surrounding the joint, communicate with the cavity of the joint.

Blood is supplied to the knee joint by branches of the popliteal artery, which passes through the popliteal fossa, and by two return branches of the anterior tibial artery and the descending genicular artery (a branch of the femoral artery). Blood from the knee joint is collected by the great saphenous and deep femoral veins. The joint is innervated by branches of the lumbar and sacral plexuses.

M. A. KON

knee joint

joint

[joint] the site of the junction or union of two or more bones of the body; its primary function is to provide motion and flexibility to the frame of the body. Some are immovable, such as the sutures" >sutures where segments of bone are fused together in the skull. Others, such as those between the vertebrae, are gliding joints and have limited motion. However, most joints allow considerable motion. The most common type are the synovial joints, which have a complex internal structure, composed not only of ends of bones but also of ligaments, cartilage, the capsule" >articular capsule, the membrane" >synovial membrane, and sometimes bursae.acromioclavicular joint the point at which the clavicle joins with the acromion.ankle joint the joint between the foot and the leg; see ankle" >ankle.arthrodial joint gliding joint.ball-and-socket joint a synovial joint in which the rounded or spheroidal surface of one bone (the “ball”) moves within a cup-shaped depression (the “socket”) on another bone, allowing greater freedom of movement than any other type of joint. See illustration. Called also polyaxial or spheroidal joint.bicondylar joint a condylar joint with a meniscus between the articular surfaces, as in the temporomandibular joint.cartilaginous joint a type of synarthrosis" >synarthrosis in which the bones are united by cartilage, providing slight flexible movement; the two types are synchondrosis" >synchondrosis and symphysis" >symphysis.composite joint (compound joint) a type of synovial joint in which more than two bones are involved.condylar joint (condyloid joint) one in which an ovoid head of one bone moves in an elliptical cavity of another, permitting all movements except axial rotation; this type is found at the wrist, connecting the radius and carpal bones, and at the base of the index finger. See illustration.diarthrodial joint synovial joint.elbow joint the synovial joint between the humerus, ulna, and radius. See also elbow.ellipsoidal joint condylar joint.facet j's the articulations of the vertebral column.fibrous joint a joint in which the union of bony elements is by continuous intervening fibrous tissue, which makes little motion possible; the three types are suture, syndesmosis, and gomphosis. Called also immovable or synarthrodial joint and synarthrosis.flail joint an unusually mobile joint, such as results when joint resection is done to relieve pain.glenohumeral joint the synovial joint formed by the head of the humerus" >humerus and the cavity" >glenoid cavity of the scapula" >scapula. Called also humeral joint and shoulder joint.gliding joint a synovial joint in which the opposed surfaces are flat or only slightly curved, so that the bones slide against each other in a simple and limited way. The intervertebral joints are this type, and many of the small bones of the wrist and ankle also meet in gliding joints. Called also arthrodial joint and plane joint.hinge joint a synovial joint that allows movement in only one plane, forward and backward. Examples are the elbow and the interphalangeal joints of the fingers. The jaw is primarily a hinge joint but it can also move somewhat from side to side. The knee and ankle joints are hinge joints that also allow some rotary movement. See illustration. Called also ginglymus.hip joint the synovial joint formed at the head of the femur" >femur and the acetabulum" >acetabulum of the hip. See illustration at hip.humeral joint joint" >glenohumeral joint.immovable joint fibrous j.knee joint the compound joint between the femur, patella, and tibia.pivot joint a synovial joint in which one bone pivots within a bony or an osseoligamentous ring, allowing only rotary movement; an example is the joint between the first and second cervical vertebrae (the atlas and axis). See illustration. Called also rotary or trochoid joint.plane joint gliding joint.polyaxial joint ball-and-socket joint.rotary joint pivot joint.sacroiliac joint the joint between the sacrum and ilium in the lower back; see also sacroiliac joint" >sacroiliac joint.saddle joint a synovial joint whose movement resembles that of a rider on horseback, who can shift in several directions at will; there is a saddle joint at the base of the thumb, so that the thumb is more flexible and complex than the other fingers but is also more difficult to treat if injured. shoulder joint humeral joint.simple joint a type of synovial joint in which only two bones are involved.spheroidal joint ball-and-socket joint.synarthrodial joint fibrous j.synovial joint a specialized joint that permits more or less free movement, the union of the bony elements being surrounded by an capsule" >articular capsule enclosing a cavity lined by membrane" >synovial membrane. Called also articulation and diarthrosis. A capillary network in the synovial membrane provides nutrients and synovial fluid to nourish and lubricate the joint space. Strong fibrous bands or cords (ligaments) give strength and security to synovial joints. The majority of the body's joints are of this type. They are divided into five types according to structure and motion: ball and socket, gliding, saddle, hinge, and pivot.

Joints.trochoid joint pivot joint.temporomandibular joint (TMJ) a bicondylar joint formed by the head of the mandible and the mandibular fossa, and the articular tubercle of the bone" >temporal bone. See also temporomandibular joint disorder.

knee joint

[TA] a compound condylar synovial joint consisting of the joint between the condyles of the femur and the condyles of the tibia, articular menisci (semilunar cartilages) being interposed, and the articulation between femur and patella. Synonym(s): articulatio genus [TA]

knee joint

(nē joynt) [TA] A compound condylar synovial joint consisting of the joint between the condyles of the femur and the condyles of the tibia, articular menisci (semilunar cartilages) being interposed, and the articulation between femur and patella.

Patient discussion about knee joint

Q. What causes inflammation of the knee joint? A. It depends on many things - the age of the person, other diseases he or she may have, whether he experienced any trauma to the joint, drugs or other substances he or she uses. Generally speaking, it may be caused by an infection (usually after trauma, very painful and abrupt inflammation, necessitates rapid treatment), rheumatologic diseases (such as rheumatoid arthritis or others, reaction to drugs or as a feature of other diseases.
You may read more here: http://en.wikipedia.org/wiki/Arthritis

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Synonyms for knee joint

noun hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella

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