The knee is a complex and highly active joint, central to human movement. Its intricate design allows for both flexibility and stability, essential for daily activities and athletic pursuits. Understanding the structures on the outside of the knee provides insight into its function and potential sources of discomfort or injury.
Key Structures of the Outer Knee
The primary structure often called the “muscle on the outside of your knee” is the iliotibial (IT) band, a thick band of connective tissue, not a muscle. This fibrous band runs along the outer thigh, originating from the iliac crest (hip bone). It receives fibers from two hip muscles: the tensor fasciae latae (TFL) and the gluteus maximus.
As the IT band extends down the thigh, it inserts onto Gerdy’s tubercle, a bony prominence on the outer tibia. Some fibers also attach to the lateral femoral epicondyle on the thigh bone. The tensor fasciae latae, a small muscle at the front and side of the hip, influences the IT band’s tension, along with the gluteus maximus and gluteus medius muscles.
Another prominent muscle contributing to the outer knee region is the vastus lateralis, the largest component of the quadriceps femoris group. Located on the side of the thigh, it originates from the femur and connects to the kneecap (patella) via the quadriceps tendon, extending to the shinbone.
How These Structures Function
The iliotibial band and its associated muscles are important for the stability and movement of both the hip and knee joints. The IT band primarily acts as a stabilizer for the hip and knee during dynamic activities like walking and running. It helps prevent excessive inward movement of the leg and provides lateral stability to the knee, especially when the leg is straight.
The tensor fasciae latae muscle assists in hip flexion, abduction (moving the leg away from the body), and internal rotation. It also helps stabilize the pelvis during standing and walking. The gluteus maximus, a hip extensor and abductor, also influences the IT band’s tension.
The vastus lateralis muscle’s main function, as part of the quadriceps, is to extend the knee. This action is important for activities such as standing up, walking, and jumping. The vastus lateralis also contributes to stabilizing the kneecap, ensuring its proper tracking during knee movement.
Common Issues Affecting the Outer Knee
Pain on the outside of the knee is frequently linked to conditions affecting the iliotibial band. Iliotibial Band Syndrome (ITBS) is a common overuse injury, prevalent among runners, cyclists, and athletes involved in repetitive knee bending. The pain, often described as aching or burning, is felt on the outer side of the knee, just above the joint.
ITBS can arise when the IT band becomes irritated or inflamed due to friction or compression as it moves over the lateral femoral epicondyle. Symptoms may worsen during or after exercise, especially with downhill running or climbing stairs. A clicking or snapping sensation, warmth, or redness may also be present.
Several factors can contribute to ITBS, including tight IT band tissue, weakness in the hip abductor muscles (such as the gluteus medius), or biomechanical issues like excessive foot pronation. Training errors, such as a sudden increase in exercise intensity or volume, running on uneven surfaces, or wearing worn-out shoes, are frequent triggers. Other conditions like lateral collateral ligament sprains or patellofemoral pain syndrome can also cause discomfort in the outer knee region.
Maintaining Outer Knee Health
Maintaining outer knee health involves preventative measures and mindful activity. Regular stretching is beneficial for the IT band and surrounding hip muscles, including side-lying leg raises, crossed-leg forward folds, and standing IT band stretches. Foam rolling can also help address muscle tension.
Strengthening the muscles that support the hip and knee is equally important. This includes targeted exercises for the glutes (e.g., lunges, squats, clamshells) and core strengthening (e.g., planks, bird-dogs). Incorporating proper warm-up and cool-down routines before and after physical activity helps prepare muscles and connective tissues. Gradually increasing training intensity and mileage, wearing supportive footwear, and regularly replacing shoes can help prevent overuse injuries. Seek professional advice for persistent pain.