Veterinary Gross Anatomy-II

ANTERIOR MUSCLES OF THE THIGH

The following are the muscles present on the anterior aspect of the thigh.

• Sartorius (Already described in medial group of muscles of thigh)
• Quadriceps femoris
  • Rectus femoris
  • Vastus lateralis
  • Vastus medialis
• Articularis genu

Quadriceps femoris

• This is a massive muscle composed of four divisions situated around the anterior, lateral and medial faces of the femur. Of these four divisions, the first three are not very distinct from each other for most of their extent. The rectus femoris arises from the ilium, while the other three arise from the femur; all terminate on the patella.
• Rectus femoris
• This is a round muscle embedded between the vastus medialis and lateralis. It extends from the cotyloid angle of the ilium to the patella.
• Origin: By two heads from the two depressions at the lowermost part of the cotyloid border of the ilium, above and in front of the acetabulum.
• Insertion: The base and anterior surface of the patella.
• Action: To extend the stifle and to flex the hip.
• Vastus lateralis
• This muscle is thicker and larger than the vastus medialis and lies on the lateral surface of the femur.
• Origin: lateral border and surface of the femur from the great trochanter to the supracondyloid fossa.
• Insertion: The lateral part of the anterior surface of the patella, and tendon of rectus femoris.
• Action: To extend the stifle.
• Vastus medialis
• This muscle is thinner and narrower than the preceding one and lies on the medial face of the femur.
• Origin: The medial and a narrow part of the anterior part of the femur.
• Insertion: The medial patellar ligament and tendon of rectus femoris.
• Action: To extend the stifle joint.
• Vastus intermedius
• This muscle consists of two parts situated deeply on the anterior face of the femur covered by the three preceding divisions.
• Origin: Anterior surface of the femur.
• Insertion: Base of the patella and femoro-patellar capsule.
• Action: To extend the stifle and raise the capsule during extension of the joint.
• Blood supply: Anterior femoral artery.
• Nerve supply: Femoral nerve.

Note: The three straight ligaments of the patella are in face of the tendons of insertion of the quadriceps muscle; the patella being developed as a sesamoid bone in the tendons .

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Articularis genu

• This is a very small muscle situated at the lower third of the anterior surface of the femur under the cover of the vastus Intermedius.
• Origin: Lower part of anterior face of the femur.
• Insertion: Femoro-patellar capsule.
• Action: To raise the capsule.
• Blood supply: Anterior femoral artery.
• Nerve supply: Femoral nerve.

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