Quadriceps muscle
Encyclopedia
The quadriceps femoris (Latin
for "four-headed muscle
of the femur"), also called simply the quadriceps, quadriceps extensor, quads, is a large muscle group that 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
.
The proper Latin plural
form of the adjective
quadriceps would be quadricipites. In modern English usage, quadriceps is used in both singular
and plural. The singular form quadricep, produced by hypercorrection
, is frequently used.
All four parts of the quadriceps muscle attach to the patella (knee cap) via the quadriceps tendon
.
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. The quadriceps, specifically the vastus medialis
, plays the important role of stabilizing the patella and the knee joint during gait.
, the quadriceps is trained by several leg exercises. Effective exercises include the squat
and leg press
. The isolation movement (i.e. targets solely the quadriceps) is the leg extension
exercise.
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "four-headed muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
of the femur"), also called simply the quadriceps, quadriceps extensor, quads, is a large muscle group that includes the four prevailing muscles on the front of the thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
. It is the great extensor
Extension (kinesiology)
In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...
muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
.
The proper Latin plural
Plural
In linguistics, plurality or [a] plural is a concept of quantity representing a value of more-than-one. Typically applied to nouns, a plural word or marker is used to distinguish a value other than the default quantity of a noun, which is typically one...
form of the adjective
Adjective
In grammar, an adjective is a 'describing' word; the main syntactic role of which is to qualify a noun or noun phrase, giving more information about the object signified....
quadriceps would be quadricipites. In modern English usage, quadriceps is used in both singular
Grammatical number
In linguistics, grammatical number is a grammatical category of nouns, pronouns, and adjective and verb agreement that expresses count distinctions ....
and plural. The singular form quadricep, produced by hypercorrection
Hypercorrection
In linguistics or usage, hypercorrection is a non-standard usage that results from the over-application of a perceived rule of grammar or a usage prescription...
, is frequently used.
Portions
It is subdivided into four separate portions or 'heads', 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 iliumIlium (bone)The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
. It is named from its straight course.
- The other three lie deep to rectus femoris and originate from the body of the femurFemurThe femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, which they cover from the trochanters to the condyles:- Vastus lateralis is on the lateral side of the femur (i.e. on the outer side of the thigh).
- Vastus medialisVastus medialisThe vastus medialis , often called the 'teardrop' muscle, is a medially located muscle of the quadriceps.-Function:The vasti appear to act largely in a co-ordinated manner throughout the control of knee extension...
is on the medial side of the femur (i.e. on the inner part thigh). - Vastus intermedius lies between vastus lateralis and vastus medialis on the front of the femur (i.e. on the top or front of the thigh), but deep to the rectus femoris. Typically, it cannot be seen without dissection of the rectus femoris.
All four parts of the quadriceps muscle attach to the patella (knee cap) via the quadriceps tendon
Quadriceps tendon
In human anatomy, the quadriceps tendon connects the quadriceps femoris muscles to the superior aspects of the patella on the anterior of the thigh and controls knee flexion and extension.It can rupture resulting in quadriceps tendon rupture....
.
Actions
All four quadriceps are powerful extensorsExtension (kinesiology)
In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...
of the knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...
joint. They are crucial in walking, running, jumping and squatting. Because rectus femoris attaches to the ilium, it is also a flexor
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
of the hip. This action is also crucial to walking or running as it swings the leg forward into the ensuing step. The quadriceps, specifically the vastus medialis
Vastus medialis
The vastus medialis , often called the 'teardrop' muscle, is a medially located muscle of the quadriceps.-Function:The vasti appear to act largely in a co-ordinated manner throughout the control of knee extension...
, plays the important role of stabilizing the patella and the knee joint during gait.
Training
In strength trainingStrength training
Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...
, the quadriceps is trained by several leg exercises. Effective exercises include the squat
Squat
The word squat, squatter or squatting can refer to:* Squatting, living in an abandoned or unused building, sometimes for political purposes...
and leg press
Leg press
The leg press is a weight training exercise in which the individual pushes a weight or resistance away from them using their legs. The term leg press also refers to the apparatus used to perform this exercise...
. The isolation movement (i.e. targets solely the quadriceps) is the leg extension
Leg extension
The leg extension is a resistance weight training exercise that targets the quadriceps muscle in the legs. The exercise is done using a machine called the Leg Extension Machine. There are various manufacturers of these machines and each one is slightly different. Most gym and weight rooms...
exercise.