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|
|Action:||Knee extension; Hip flexion (R.Fem. only)|
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.
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:
The quadriceps is also involved in Lombard's Paradox.
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.
- Duke Orthopedics quadriceps_muscle
- Muscles/Quadriceps at exrx.net
- Roche Lexicon - illustrated navigator, at Elsevier 39960.000-1
- Anatomy of the Quadriceps Muscles - Fitstep.com
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 As such, some of the information contained herein may be outdated.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.