Patella (Kneecap)
What is the Patella
Patella, commonly known as the kneecap, is the largest sesamoid bone of the body. It is located at the front of the knee like a cap, protecting the knee joint. It is characterized as a sesamoid bone as it remains embedded within the quadriceps tendon.
Where is the Patella Located
The location of the patella can be felt by touching the knee. The bone you sense is the patella whenever you touch the knee.
In anatomical terms, the patella is located between the femur of the upper leg and the tibia-fibula of the lower leg. More precisely, it is positioned in front of the patellar surface, a groove between the condyles of the distal end of the femur.
Quick Facts
| Type | Sesamoid bone |
| How many are there in the human body | 2 (1 in each knee) |
| Articulates with | Femur |
Functions
- Protect the knee joint from any physical injury.
- Allow smooth knee movement by acting as a pulley for the quadriceps tendon during flexion and extension of the lower leg. As the patella sits in front of the femoral condyles, it increases or decreases the angle at which the quadriceps tendon pulls the tibial shaft, thus extending or flexing the lower leg.
Anatomy of the Patellar Region
Patella is a thick, flat, triangular bone, having concave anterior and convex posterior surfaces. The posterior surface articulates with the femur and is marked by two shallow depressions or facets, medial and lateral.
Being triangular, it has a pointy end and three sides. The pointy end is the apex and the three sides from the borders. The side lying medially is called the medial border, the one facing laterally is called the lateral border, and the one which lies proximally is referred to as the superior border or base. There are some rough markings on the lateral and medial borders of the patella where vasti lateralis and medialis attach.
Bony Landmarks and Articular Surfaces
Base
The base is the blunt, broad, convex, nonarticular proximal end of the bone, opposite the apex. It serves as an attachment point for the quadriceps tendon.
Apex
The apex is the pointy, nonarticular tip of the bone, directing downwards. It serves as an attachment site for the patellar ligament, an inferior extension of the quadriceps tendon.
Lateral articular facet
It articulates with the lateral condyle of the femur.
Medial articular facet
It articulates with the medial condyle of the femur and is smaller than the lateral articular facet.
FAQs
Ans. Yes, the patella is a short bone.
Ans. The patellar tendon and quadriceps tendon hold the patella in place.
Ans. Yes, the patella is a floating bone as it does not directly articulate with other bones in the knee joint.
Ans. When they are born, babies have a cartilaginous patella that develops during fetal growth. This cartilage then gradually hardens and becomes the bony kneecap as they grow up.
References
- The Patella – Teachmeanatomy.info
- Patella – Kenhub.com
- Patella – Radiopaedia.org
- Anatomy, Bony Pelvis and Lower Limb, Knee Patella – Ncbi.nlm.nih.gov
- Patella – Sciencedirect.com
