Quadriceps femoris muscle

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Quadriceps femoris muscle
Image:Illu lower extremity muscles.jpg
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.

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

Knee diagram	Gray351.png Capsule of right knee-joint (distended). Lateral aspect.	Gray432 color.png Cross-section through the middle of the thigh.	Gray430.png Anterior aspect of right leg.
Gray1238.png Front and medial aspect of right thigh.	Gray1240.png Lateral aspect of right leg.	LegExtensionMachineExercise.JPG The leg extension is an isolation exercise.

External links

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 As such, some of the information contained herein may be outdated.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.

v • d • e List of muscles of lower limbs
ILIAC REGION/ILIOPSOAS	psoas major/psoas minor - iliacus
BUTTOCKS	gluteals: (maximus, medius, minimus) - tensor fasciae latae lateral rotator group: piriformis - inferior gemellus - obturator internus - superior gemellus - quadratus femoris
THIGH	anterior compartment: sartorius - quadriceps (rectus femoris, vastus lateralis, vastus intermedius, vastus medialis) - articularis genu posterior compartment/hamstring: biceps femoris - semitendinosus - semimembranosus medial compartment: pectineus - obturator externus - gracilis - adductor (longus, brevis, magnus)
LEG	anterior compartment: tibialis anterior - extensor hallucis longus - extensor digitorum longus - peroneus tertius posterior compartment: superficial - calf/triceps surae (gastrocnemius, soleus) - plantaris posterior compartment: deep - tarsal tunnel (flexor hallucis longus, flexor digitorum longus, tibialis posterior) - popliteus lateral compartment: peroneus muscles (longus, brevis)
FOOT	dorsal - extensor hallucis brevis - extensor digitorum brevis plantar - 1st layer (abductor hallucis, flexor digitorum brevis, abductor digiti minimi) plantar - 2nd layer (quadratus plantae, lumbrical muscle) plantar - 3rd layer (flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis) plantar - 4th layer (dorsal interossei, plantar interossei)