The vastus muscles are three of the four muscles that make up the
quadriceps femoris muscle
The quadriceps femoris muscle (, also called the quadriceps extensor, quadriceps or quads) is a large muscle group that includes the four prevailing muscles on the front of the thigh. It is the sole extensor muscle of the knee, forming a large ...
of the
thigh
In human anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb.
The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone ...
. The three muscles are the
vastus intermedius
The vastus intermedius () (Cruraeus) arises from the front and lateral surfaces of the body of the femur in its upper two-thirds, sitting under the rectus femoris muscle and from the lower part of the lateral intermuscular septum. Its fibers en ...
, the
vastus lateralis
The vastus lateralis (), also called the vastus externus, is the largest and most powerful part of the quadriceps femoris, a muscle in the thigh. Together with other muscles of the quadriceps group, it serves to extend the knee joint, moving the l ...
, and the
vastus medialis
The vastus medialis (vastus internus or teardrop muscle) is an extensor muscle located medially in the thigh that extends the knee. The vastus medialis is part of the quadriceps muscle group.
Structure
The vastus medialis is a muscle present i ...
located in the middle, on the outside, and inside of the thigh, respectively. The fourth muscle is the
rectus femoris muscle
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius (deep to the rectus femoris), and the vastus lateralis. All four parts of the quadriceps muscle attach t ...
a large fleshy
muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
which covers the front and sides of the
femur
The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...
.
Vastus intermedius
The vastus intermedius arises from the front and
lateral
Lateral is a geometric term of location which may refer to:
Healthcare
*Lateral (anatomy), an anatomical direction
*Lateral cricoarytenoid muscle
*Lateral release (surgery), a surgical procedure on the side of a kneecap
Phonetics
*Lateral cons ...
surfaces of the
body of the femur in its upper two-thirds, sitting under the rectus femoris muscle and from the lower part of the
lateral intermuscular septum. Its fibers end in a superficial
aponeurosis
An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...
, which forms the deep part of the
quadriceps tendon
In human anatomy, the quadriceps tendon works with the quadriceps muscle to extend the leg. All four parts of the quadriceps muscle attach to the shin via the patella (knee cap), where the quadriceps tendon becomes the patellar ligament. It attach ...
.
The vastus medialis and vastus intermedius appear to be inseparably united, but when the rectus femoris has been reflected a narrow interval will be observed extending upward from the
medial border of the
patella
The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as m ...
between the two muscles, and the separation may be continued as far as the lower part of the
intertrochanteric line
The intertrochanteric line (or ''spiral line of the femur''White (2005), p 256 ) is a line located on the anterior side of the proximal end of the femur.
Structure
The rough, variable ridge stretches between the lesser trochanter and the greater t ...
, where, however, the two muscles are frequently continuous.
Vastus lateralis
The vastus lateralis is the largest and most powerful of the three vasti muscles. It arises from the several areas of the femur, including the upper part of the intertrochanteric line; the lower,
anterior
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
borders of the
greater trochanter
The greater trochanter of the femur is a large, irregular, quadrilateral eminence and a part of the skeletal system.
It is directed lateral and medially and slightly posterior. In the adult it is about 2–4 cm lower than the femoral head.Stan ...
, to the outer border of the
gluteal tuberosity
The gluteal tuberosity is the lateral one of the three upward prolongations of the linea aspera of the femur, extending to the base of the greater trochanter. It serves as the principal insertion site for the gluteus maximus muscle.
Structure
T ...
, and the upper half of the outer border of the
linea aspera
The linea aspera ( la, rough line) is a ridge of roughened surface on the posterior surface of the shaft of the femur. It is the site of attachments of muscles and the intermuscular septum.
Its margins diverge above and below.
The linea asper ...
. These form an aponeurosis, a broad flat tendon which covers the upper three-quarters of the muscle. From the inner surface of the aponeurosis, many muscle fibres originate. Some additional fibres arise from the tendon of the
gluteus maximus
The gluteus maximus is the main extensor muscle of the hip. It is the largest and outermost of the three gluteal muscles and makes up a large part of the shape and appearance of each side of the hips. It is the single largest muscle in the human ...
muscle, and from the
septum
In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate.
Examples
Human anatomy
* Interatri ...
between the vastus lateralis and short head of the
biceps femoris
The biceps femoris () is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group.
Structure
It has two heads of origin:
*the ''long h ...
.
The fibers form a large fleshy mass, attached to a second strong aponeurosis, placed on the deep surface of the lower part of the muscle. This lower aponeurosis becomes contracted and thickened into a flat tendon that attaches to the outer border of the
patella
The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as m ...
, and subsequently joins with the
quadriceps femoris tendon, expanding the
capsule of the knee joint.
Vastus medialis
The vastus medialis arises medially along the entire length of the femur, and attaches with the other muscles of the quadriceps in the quadriceps tendon.
The vastus medialis muscle originates from a continuous line of attachment on the femur, which begins on the front and middle side (anteromedially) on the intertrochanteric line of the femur. It continues down and back (posteroinferiorly) along the
pectineal line and then descends along the inner lip of the linea aspera and onto the medial supracondylar line of the femur. The fibers converge onto the medial part of the quadriceps tendon and the medial border of the patella.
The ''obliquus genus'' muscle is the most distal segment of the vastus medialis muscle. Its specific training plays an important role in maintaining patella position and limiting injuries to the knee. With no clear delineation, it is simply the most distal group of fibers of the vastus medialis.
Additional images
File:Gray244.png, Right femur. Anterior surface.
File:Gray245.png, Right femur. Posterior surface.
File:Gray430.png, Muscles of the iliac and anterior femoral regions.
File:Gray432 color.png, Cross-section through the middle of the thigh.
File:Slide7CCCC.JPG, Vastus intermedius muscle
File:Slide9WWWW.JPG, Vastus intermedius muscle
File:Slide2EA.JPG, Muscles of thigh. Cross section.
File:Slide1DEEA.JPG, Muscles of Thigh. Anterior views.
References
{{Muscles of lower limb
Knee extensors
Muscles of the quadriceps
Anterior compartment of thigh
Muscles of the lower limb