Quadriceps

Other Names

• Thigh (Front)
• Quads

Heads

1. Rectus Femoris
2. Vastus Lateralis (Externus)
3. Vastus Intermedius
4. Vastus Medialis (Internus)

Movement

Knee

• Extension [1, 2, 3, 4 ]

Hip

• Flexion [1 ]

Attachments

Origin

• Ilium [1 ]
  • Iliac Spine (Anterior Inferior)
• Femur
  • Lateral Surface [2 ]
  • Anterior Surface [3 ]
  • Medial Surface [4 ]

Insertion

• Tibia [1, 2, 3, 4 ]
  • Tuberosity
    • Patellar Tendon
      • Patella

Related Muscles

• Iliopsoas
• Pectineus
• Sartorius
• Tensor Fasciae Latae

Comments

The biarticulate rectus femoris [1 ] enters passive insufficiency through the completion of knee flexion when the hips are more extended or through the completion of hip extension when the knees are more flexed. The biarticulate rectus femoris [1 ] enters active insufficiency  through the completion of knee extension when the hips are more flexed (other heads of the quadriceps [2, 3, 4 ] become more active) or through the completion of hip flexion when the knees are more extended (other hip flexors  become more active).

See vastus medialis weakness [4]. Also, see pulley-like arrangements in body.