What is the Patella?

The patella, commonly known as the kneecap, is a small but important bone located in the front of the knee. It plays a significant role in knee mechanics, aiding in movement and stability. This article will explore the structure, function, and abnormalities patella.

The Anatomy of the Patella

The patella is a flat, triangular bone that sits within the tendon of the quadriceps muscle, the major muscle group on the front of the thigh. It is unique as it is one of the few bones in the body that is entirely encased within a tendon. This setup allows the patella to slide up and down a groove on the femur (thighbone) as the knee bends and straightens.

Function of the Patella

The primary function of the patella is to increase the leverage that the quadriceps tendon can exert on the femur, enhancing the muscle’s ability to straighten the leg. The patella acts as a fulcrum, providing a mechanical advantage to the muscles of the thigh. This function is important for numerous activities including running, jumping, and climbing stairs.

Imaging the Patella

X-ray Imaging

X-ray is often the first imaging technique used when a patellar injury or disorder is suspected. It provides clear images of bone structure, allowing for the detection of fractures and alignment issues in the patella. An X-ray can help determine the position of the patella in relation to the femur and tibia, which is important for diagnosing conditions such as patellar misalignment or dislocation.

Advantages of X-ray Imaging

• Quick and widely available
• Effective for detecting bone fractures and structural abnormalities

Magnetic Resonance Imaging (MRI)

MRI is a more sophisticated imaging technique that uses magnets and radio waves to create detailed images of both bones and soft tissues. This makes it particularly useful for diagnosing soft tissue injuries around the patella, such as ligament tears and tendonitis. MRI is also employed to assess the condition of cartilage within the knee joint.

Benefits of MRI

• Non-invasive and does not use ionizing radiation
• Provides detailed images of soft tissue, including muscles, tendons, and ligaments

Computed Tomography (CT) Scan

A CT scan can be helpful when complex bone fractures are suspected, or when a detailed, three-dimensional image is needed for surgical planning. CT scans offer more detailed visualization of bone than standard X-rays and can be important in the assessment of the patella for surgical procedures.

Utility of CT Scans

• Provides high-resolution bone images
• Useful for detailed assessment and surgical planning

Common Conditions Affecting the Patella

Patellar Tendinitis (Jumper’s Knee)

Patellar tendinitis, frequently referred to as jumper’s knee, is an overuse injury affecting the tendon that connects the patella to the shinbone. This condition is prevalent among athletes who participate in sports that require frequent jumping, such as basketball and volleyball. Symptoms typically include pain just below the kneecap, which worsens with activity.

Patellofemoral Pain Syndrome (Runner’s Knee)

This syndrome is common among young athletes but can also occur in older adults due to arthritis of the kneecap. Symptoms include pain behind or around the kneecap, especially when sitting with bent knees, squatting, or using stairs.

Management of patellofemoral pain syndrome typically includes exercises to strengthen the muscles around the knee, improving alignment and reducing pressure on the patella. Orthotics and proper footwear may also help, along with pain management strategies such as ice and non-steroidal anti-inflammatory drugs (NSAIDs).

Patellar Dislocation

Patellar dislocation occurs when the patella slips out of its normal position, usually to the outside of the knee. This can be caused by a direct blow or a sudden twist of the knee. Symptoms include severe pain, swelling, and the knee may appear deformed.

Immediate treatment involves reducing the dislocation (“reducing” the patella), which a medical professional typically performs. Post-dislocation treatment includes physical therapy to strengthen the muscles around the knee and possibly a brace to stabilize the knee. In severe cases, surgery might be required to repair or reconstruct the damaged ligaments that normally keep the patella in place.

Patellar Fracture

A patellar fracture is a break in the kneecap that can occur from a direct impact or a severe contraction of the quadriceps muscle. Symptoms of a patellar fracture include immediate and severe pain, swelling, and an inability to straighten the knee.

Treatment for a patellar fracture may vary depending on the type and severity of the fracture. Some fractures can be managed with a cast or splint, while others require surgical intervention to realign and fix the broken pieces of bone.


The patella, or kneecap, is more than just a small bone in your knee; it is a critical component in the biomechanics of leg movement. Its unique position and function allow for efficient movement and force application during physical activities.  Imaging plays an important role in detecting abnormalities.

Disclaimer: The content of this website is provided for general informational purposes only and is not intended as, nor should it be considered a substitute for, professional medical advice. Do not use the information on this website for diagnosing or treating any medical or health condition. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider.

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