| Vastus muscles | |
|---|---|
 Muscles of lower extremity (Rectus Femoris has been removed) | |
| Details | |
| Origin | Femur |
| Insertion | Quadriceps tendon |
| Artery | Femoral artery |
| Nerve | Femoral nerve |
| Actions | Extension ofknee joint |
| Anatomical terms of muscle | |
Thevastus muscles are three of the four muscles that make up thequadriceps femoris muscle of thethigh. The three muscles are thevastus intermedius, thevastus lateralis, and thevastus medialis located in the middle, on the outside, and inside of the thigh, respectively. The fourth muscle is therectus femoris muscle a large fleshymuscle which covers the front and sides of thefemur.
The vastus intermedius arises from the front andlateral surfaces of thebody of the femur in its upper two-thirds, sitting under the rectus femoris muscle and from the lower part of thelateral intermuscular septum. Its fibers end in a superficialaponeurosis, which forms the deep part of thequadriceps tendon.
The vastus medialis and vastus intermedius appear to be inseparably united, but when the rectus femoris has been reflected[when defined as?] a narrow interval will be observed extending upward from themedial border of thepatella between the two muscles, and the separation may be continued as far as the lower part of theintertrochanteric line, where, however, the two muscles are frequently continuous.
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 borders of thegreater trochanter, to the outer border of thegluteal tuberosity, and the upper half of the outer border of thelinea aspera. 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 thegluteus maximus muscle, and from theseptum between the vastus lateralis and short head of thebiceps femoris.
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 thepatella, and subsequently joins with thequadriceps femoris tendon, expanding thecapsule of the knee joint.
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.[1] 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 thepectineal 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.[1] Theobliquus 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.
