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Medicine LibreTexts

7.8B: Patella (The Knee)

The patella (knee cap) is the bone between the fibula and femur.

 

LEARNING OBJECTIVES

 

Identify the purpose of the patella

 

KEY TAKEAWAYS

Key Points

 

  • The primary functions of the patella are to enhance leg extension and protect the joint of the knee.
  • The patella is a bone embedded within a tendon. This means it is a sesamoid bone.

 

Key Terms

 

  • patella: A sesamoid bone found in the knee, commonly known as the knee cap.
  • sesamoid: A bone embedded within a tendon.

The patella or knee cap is the bone between the fibula and femur. Each leg has a patella to protect its knee joint. The patella serves two functions:

  1. To protect the knee from physical trauma.
  2. To enhance the leverage that the quadriceps tendon can exert on the femur, thereby increasing muscle efficiency.

The apex of the patella faces inferiorly and connects to the tibia tuberosity through the patella ligament that attaches to the anterior surface. The base of the patella faces superiorly and is the attachment point for the quadriceps tendon.

The posterior surface of the patella contains the medial and lateral facets that articulate with the condyles of the femur. The lower posterior region of the patella has vascular canaliculi, small channels within the bone, which form the infrapatellar fat pad.

This illustration of the knee joint shows the position of the patella relative to the articulation of the femur and the tibia.

Knee Joint: This image shows the position of the patella relative to the articulation of the femur and the tibia.