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Anatomy Atlases: Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System: Alphabetical Listing of Muscles: Q: Quadriceps Femoris

Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System: Alphabetical Listing of Muscles: Q

Quadriceps Femoris

Ronald A. Bergman, PhD
Adel K. Afifi, MD, MS
Ryosuke Miyauchi, MD

Peer Review Status: Internally Peer Reviewed

The deep parts of the quadriceps are not subject to many variations. The vasti are sometimes bilaminar. This, in the case of vastus lateralis, is an accentuation of a typical feature. The vasti may be continuous with the rectus femoris, and all three parts may be united into a common fleshy mass. The absence of rectus femoris, as well as the entire muscle mass, has been reported.

Macalister reported the variations of the quadriceps as follows;

1. An origin from the anterior superior spine of the ilium was found joining the straight head;
2. A split curved head, part being outside, and a part between the layers of the hip-joint capsule;
3. A double origin from the inferior spine;
4. A continuity of the acetabular and spinous heads;
5. With no acetabular origin;
6. Isenflamm described a bursa between the lateral tendon and the brim of the acetabulum;
7. Diemerbröck described a double long head, which Macalister also found;
8. A large fasciculus of its tendon, passing across the front of the patella, was separated from the bone by the deepest part of the prepatellar bursa;
9. The relation of this muscle to the rest of the extensor is variable; sometimes at its insertion it is inseparable from the cruraeus (vastus intermedius), at other times Macalister saw the two vasti uniting over the tendon of this muscle, thus forming a canal in which the rectus tendon ran to its insertion; or the vastus externus (lateralis) may be inserted into the outer border of its tendon, while the vastus internus (medialis) and cruraeus vastus intermedius) lie beneath.

Cruraeus (vastus intermedius) may arise as high as the anterior intertrochanteric line, or not within an inch (2.54 cm) of that line, and it may descend as far as a half an inch (1.27 cm.) to an inch above the knee (Sandifort, 1769), or more commonly it does not extend below a point three to four inches above the knee. This muscle is usually inseparable from the vastus internus (medialis), so much so that Nuhn and Cruveilhier regard them both as one. Cruraeus (vastus intermedius) and subcruraeus (m. articularis genu) are frequently united, or, when no subcruraeus is present deep fibers are, rarely, attached to the synovial membrane of the knee. Vastus intermedius is composed of muscle lamellae superimposed concentrically about the shaft of the femur. The deepest, most distal of these lamallae is called articularis genu. The fiber bundles of this layer are inserted into the capsule of the joint or into the the superior margin of the patella, and ultimately, through the ligamentum patellae, into the tuberosity of the tibia. Articularis genu may be absent.

Macalister continues his account of the variations of quadriceps as follows: The Vastus internus (medialis) varies only by being-

1. Bilaminar (5 cases);
2. It may be united with cruraeus (vastus intermedius);
3. The more distal fasciculi may be more or less separate at their insertion, passing into the medial condyle of the tibia by a separate tendon;
4. It may be doubled.

Vastus externus (vastus lateralis) may also be bilaminar and united with vastus medialis at its insertion, or to vastus intermedius, or to the rectus, or to a lateral slip of articularis genu, when this muscle consists of two lateral slips, but this is very rare. Doubling of vastus medialis and vastus lateralis mimics the condition found in many birds.

Sub-cruraeus (articularis genu) is found to be liable to atrophy, absence, splitting, or fusion, with vastus intermedius. Its discovery is credited to Dupré, in his work, "Sur les Sources de la Synovie, 1699. Albinus also described the muscle in "Annotations Acad., lib. iv., cap 5, p.27, ~1734. The muscle may be inserted at either side of the knee, or into the upper part of the synovial membrane; its lateral slips, when split, are usually equal.

Rarely, a slip (rectus accessorius) may arise from a tendon at the edge of the acetabulum and insert into the ventral edge of vastus lateralis. The quadriceps of the thigh corresponds in a general way to the triceps group (including anconeus) in the arm.

Syn.: m. extensor cruris. Rectus femoris: extensor cruris medialis superficialis (Meckel),rectus anterior (Krause), Gerader Schenkelmuskel, Droit antérieur. Vastus lateralis: vastus externus (Henle), extensor cruris vastus s. externus (Meckel), Aeusserer dicker Schenkelmuskle, Aeusserer Unterschenkelstrecker. Vastus medialis: vastus internus (Henle). Vastus intermedius: cruralis s. cureus s. femoreus (Henle), Vastus medius (Krause), Tiefer Unterschenkelstrecker. The three portions, the vasti: extensor triceps (M.J. Weber), with rectus femoris: extensor quadriceps (Hyrtl).


Drachmann, A.G. (1837) Translation by J.W. Moore. Case of congenital absence of the quadriceps extensor crurius muscle. J. Anat. Physiol. 7:310-311.

Gruber, W. (1878) Beobachtungen über den Mangel des Musculus quadratus femoris. Arch. Path. Anat. Physiol. Klin. Med. 73:346-348.

Gruber, W. (1879) Nachtrag zu den Beobachtungen uber den Mangel des Musculus quadratus femoris. Arch. Path. Anat. Physiol. Klin. Med. 77:131

Gruber, W. (1880) Ein bilaminärer Musculus vastus externus biceps. Arch. Path. Anat. Physiol. Klin. Med. 82:473-474.

Gruber, W. (1888) Ein Musculus rectus femoris accessoris. Arch. Path. Anat. Physiol. Klin. Med. 114:367-368.

Macalister, A. (1875) Observations on muscular anomalies in the human anatomy. Third series with a catalogue of the principal muscular variations hitherto published. Trans. Roy. Irish Acad. Sci. 25:1-130.

Takeshige, A., Okinaga, H., Shirai, N., and M.Tanaka. (1960) Variation of the origin of the M. quadriceps femoris. Kurume Igakkai Zasshi 23:861-864.

Williams, W.R. (1879) The anatomy of the quadriceps extensor cruris. J. Anat. Physiol. 13:204-218.

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