Femur Bone - Anterior and Posterior Markings
Patella Bone – Anterior and Posterior Views
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The patella, or kneecap, is the largest sesamoid bone of the human body. It is located in the knee, invested within the tendon of quadriceps femoris muscle. Hence, this tendon is called the patellar tendon.
| Key points about the patella | |
|---|---|
| Location | Within the tendon of quadriceps femoris muscle in the knee |
| Anterior surface | Subcutaneous and palpable |
| Posterior surface | Features two articular facets: lateral and medial; articulates with lateral and medial condyles of the femur forming the patellofemoral joint |
| Function | Improves efficiency of the knee joint by acting as a fulcrum, moving the patellar tendon away from the joint between the femur and tibia; extends lever arm of tendon, enhancing force exerted on tibia when knee straightens and optimizing leg movement |
The patella is usually described as being triangular in shape. As such, it features superior, medial and inferior margins. The lower border of the patella is convex and pointy, which is why it is called the apex (literally meaning the “tip”). The superior margin is called the base, which serves as an attachment point for the quadriceps tendon.
The patella has two surfaces, anterior and posterior. The anterior surface is subcutaneous and it is palpable in the knee region. The posterior surface features two articular facets, namely lateral and medial, that articulate with the lateral and medial condyles of the femur. The joint between the patella and femur is called the patellofemoral joint.
Anterior and posterior views of the patella (labeled)
Function
The function of the patella is to improve the efficiency of the knee joint. It acts as a fulcrum, moving the patellar tendon away from the joint between the femur and tibia. By doing so, it extends the lever arm of the tendon. This increased distance enhances the force exerted on the tibia when the knee straightens, thereby optimizing the function and movement of the leg.
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References
- Open Anatomy. (n.d.). TA2 Viewer. Retrieved April 5, 2023, from https://ta2viewer.openanatomy.org/
- Moore, K. L. (2018). Clinically Oriented Anatomy (8th ed.). Philadelphia, PA: Wolters Kluwer.
- Drake, R. L., Vogl, A. W., & Mitchell, A. W. M. (2015). Gray’s Anatomy for Students (3rd ed.). Edinburgh, Scotland: Churchill Livingstone.
- Standring, S. (2021). Gray’s Anatomy (42tst ed.). Edinburgh: Elsevier Churchill Livingstone.
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