Patella

Jai Ganesh · 2025-05-08 17:42:39

Patella

Gist

The patella ( pl. : patellae or patellas), also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint.

Summary

The patella (pl.: patellae or patellas), also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats, birds and dogs, but not in whales, or most reptiles.

In humans, the patella is the largest sesamoid bone (i.e., embedded within a tendon or a muscle) in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about four years of age.

Details

The patella is your kneecap. Even though it protects your joint, it’s not just a cover for your knee. It also helps muscles, tendons and ligaments work correctly, as well as helps you move your knee. If your bones are weakened by osteoporosis, you have an increased risk for fractures.

Overview

The patella is your kneecap, the bone at the front of your knee joint.

What is the patella?

The patella is your kneecap. It’s the bone at the front of your knee joint. It’s the biggest bone in your body embedded in a tendon (a sesamoid bone). Your patella helps your quadriceps muscle move your leg, protects your knee joint, and supports lots of important muscles, tendons and ligaments.

Traumas that hurt your knee are the most common patella injuries, including dislocations and bone fractures. If you do experience an injury, you might need surgery to repair your bone and physical therapy to help you regain your strength and ability to move.

Your patella — like all bones — can be affected by osteoporosis.

Function:

What does the patella do?

Your patella has two main jobs:

* Working with your quadriceps muscle to extend and straighten your leg.
* Protecting your knee joint.

Anatomy:

Where is the patella located?

The patella is at the front of your knee and covers the knee joint itself. It’s a bridge between your quad muscle and your lower leg.

What does the patella look like?

The patella is shaped like an oval with a slight point at the bottom. The top (base) is connected to your quad muscle by the quadriceps tendon. The patellar ligament connects the bottom (apex) of your patella to your tibia (shin bone).

The patella’s medial facet (the side closer to the inside of your body) articulates (moves) with your femur’s medial condyle. The lateral facet (the side closer to the outside of your body) moves with your femur’s lateral condyle.

These parts and labels are usually more for your healthcare provider to use, as they describe where you’re having pain or issues. If you ever break your patella — a patellar fracture — your provider might use some of these terms to describe where your bone was damaged.

How big is the patella?

Most adults’ patellae (the plural for patella) are around 1.75 inches long and 1.5 inches wide.

Conditions and Disorders:

What are the common conditions and disorders that affect the patella?

Lots of conditions cause knee pain (anterior knee pain or chondromalacia patella). Many of the most common causes of knee pain damage the patella or the area around it, including:

* Patellofemoral pain syndrome.
* Patellar dislocations.
* Patellar instability.
* Patella fractures.
* Patellar tendinitis.

Patellar dislocation vs. patellar subluxation

Some people might think they have a patellar dislocation when they actually have a patellar subluxation.

A subluxation is a partial dislocation. It means that your bone is unstable in the joint and may have strayed a little out of place, but it hasn’t popped all the way out. When you have a patella subluxation, your kneecap still fits in its groove and you can still walk. You may feel uncomfortable or unsteady, and you may hear a popping noise as your patella moves. Injuries or your joint being too loose can cause patellar subluxation.

Osteoporosis

Osteoporosis can affect any bone in your body, including your patella. Osteoporosis weakens bones, making them more susceptible to sudden and unexpected fractures. Many people don’t know they have osteoporosis until after it causes them to break a bone. There usually aren’t obvious symptoms.

Women and adults older than 50 have an increased risk for developing osteoporosis. Talk to your provider about a bone density test that can catch osteoporosis before it causes a fracture.

What tests are done on the patella?

The most common test providers do on the patella is the patella reflex test.

Your provider will tap your knee just below your patella with a special hammer. The sudden stimulation on your tendons triggers an involuntary reflex — a reaction you can’t control — which should make your leg extend. This is the patellar reflex.

Your provider might perform this test as part of your routine examination or if they suspect something is affecting your body’s nervous system.

If you’ve experienced a patellar injury or fracture, your provider or surgeon might need imaging tests, including:

* X-rays.
* Magnetic resonance imaging (MRI).
* CT scan.

What are common treatments for the patella?

Usually, your patella won’t need treatment unless you’ve experienced an injury or fracture or have knee pain.

Many issues that affect your patella can be treated with similar treatments, including:

* Wearing a brace or other immobilizing device.
* Resting or avoiding the activity that caused your injury.
* Physical therapy.
* At-home treatments like icing and over-the-counter pain relievers.

Patella fracture treatment

How your fracture is treated depends on which type it is and what caused it. You’ll need some form of immobilization — like a splint or cast — and might need surgery to realign (set) your bone to its correct position and secure it in place so it can heal. Ask your provider or surgeon how long it will take your specific fracture to recover.

Osteoporosis treatment

Treatments for osteoporosis can include:

* Exercise.
* Vitamin and mineral supplements.
* Prescription medications.

Exercise and taking supplements are usually all you’ll need to prevent osteoporosis. A healthcare provider can help develop a treatment plan that’s customized for you and your bone health.

Additional Information

The patella is also known as the kneecap. It sits in front of the knee joint and protects the joint from damage.

It is the largest sesamoid bone in the body, and lies within the quadriceps tendon. The kneecap is an example of a bone we are all familiar with, and which has a significant functional role.

Anatomy

The patella is the largest sesamoid bone in the body and it lies within the quadriceps tendon in front of the knee joint. The bone originates from multiple ossification centres that develop from the ages of three to six, which rapidly coalesce. The patella is a thick, flat, triangular bone with its apex pointing downwards. The bone has a medial and lateral border, as well as its base which lies proximally.

The patella is a dense trabecular bone with a thin compact lamina covering it. The attachment of the quadriceps muscle if found on the superior surface extends distally onto the anterior surface. The rough marking found at the lateral and medial borders of the patella represent the attachments of vasti lateralis and medialis, and those at the apex represent the attachment of the patellar ligament.

The apex of the patella gives rise to the patellar ligament, which inserts onto the tibial tuberosity on the anterior surface of the tibia. The middle third of the patella has various vascular openings that allow for arteries to penetrate and supply the bone.

The patella is stabilized by the horizontal fibers of vastus medialis, as well as the anterior projection of the lateral femoral condyle. The tension in the medial patellar retinaculum also helps in its stability.

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#1 2025-05-08 17:42:39

Patella

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