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Quadriceps femoris muscle



Quadriceps femoris muscle
Muscles of lower extremity. (Rectus femoris removed to reveal the vastus intermedius.)
Latin musculus quadriceps femoris
Gray's subject #128 470
Origin: combined rectus femoris and vastus muscles
Insertion:
Artery: femoral artery
Nerve: Femoral nerve
Action: Knee extension; Hip flexion (R.Fem. only)
Antagonist: Hamstring
Dorlands/Elsevier m_22/12550408
"Quads" redirects here. For other uses see Quad

The quadriceps femoris (quadriceps, quadriceps extensor, guads or quads) includes the four prevailing muscles on the front of the thigh. It is the great extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur.

Additional recommended knowledge

It is subdivided into separate portions, which have received distinctive names.

  • Rectus femoris occupies the middle of the thigh, covering most of the other three quadriceps muscles. It originates on the ilium. It is named from its straight course.
  • The other three lie deep to rectus femoris and originate from the body of the femur, which they cover from the trochanters to the condyles:
    • Vastus lateralis is on the lateral side of the femur.
    • Vastus medialis is on the medial side of the femur.
    • Vastus intermedius lies between vastus lateralis and vastus medialis on the front of the femur.

All four parts of the quadriceps muscle attach to the patella via the quadriceps tendon.

The quadriceps is also involved in Lombard's Paradox.

Actions

All four quadriceps are powerful extensors of the knee joint. They are crucial in walking, running, jumping and squatting. Because rectus femoris attaches to the ilium, it is also a flexor of the hip. This action is also crucial to walking or running as it swings the leg forward into the ensuing step.



Additional images

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Quadriceps_femoris_muscle". A list of authors is available in Wikipedia.
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