- Although the term "quadriceps" technically may refer to any four-headed muscle, it usually refers to and is synonymous with the quadriceps muscle of the thigh, the large muscle that comes down the femur (the bone of the upper leg), goes over the patella (the kneecap) and anchors into the top of the tibia (the big bone in the lower leg). The function of the quadriceps is to extend (to straighten out) the leg. President Bill Clinton had surgery in 1997 to repair the quadriceps tendon in his right knee, which he tore stumbling on steps. The quadriceps stretch exercise is designed to help prevent this type of injury. For those who are into Latin, this muscle's full formal name is musculus quadriceps femoris. For those who prefer nicknames, it is the quad.
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* * *quad·ri·ceps 'kwäd-rə-.seps n a large extensor muscle of the front of the thigh divided above into four parts which include the rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis, and which unite in a single tendon to enclose the patella as a sesamoid bone at the knee and insert as the patellar ligament into the tuberosity of the tibia called also quadriceps femoris, quadriceps muscle
* * *n.one of the great extensor muscles of the legs. It is situated in the thigh and is subdivided into four distinct portions: the rectus femoris (which also flexes the thigh), vastus lateralis, vastus medialis, and vastus intermedius.
* * *quad·ri·ceps (kwodґrĭ-seps) [quadri- + L. caput head] four headed; possessing four heads.
Medical dictionary. 2011.