What type of joint is the knee and why is it considered complex?

The knee is the largest and most complex synovial joint in the body. It functions as a modified hinge joint formed by three articulations: medial and lateral femorotibial condylar joints and the patellofemoral joint, making it structurally intricate despite its strength in movement.

What are the main ligaments of the knee and their functions?

The knee has several key ligaments: collateral ligaments (medial and lateral) provide side-to-side stability, while cruciate ligaments (anterior and posterior) prevent forward and backward tibial displacement. Other ligaments like the patellar and capsular ligaments support overall joint structure and movement.

How do the medial and lateral menisci differ in structure and injury risk?

The medial meniscus is C-shaped and attached to the tibial collateral ligament, making it less mobile and more prone to injury. In contrast, the lateral meniscus is O-shaped and mobile due to its attachment to the popliteus muscle, resulting in a lower risk of tears.

What movements does the knee joint allow and which muscles are involved?

The knee permits flexion and extension, primarily driven by the hamstrings (flexion) and quadriceps femoris (extension), as well as rotation (medial and lateral), involving muscles like semitendinosus for medial rotation and biceps femoris for lateral rotation.

What is the 'unhappy triad' knee injury?

The unhappy triad refers to a common sports injury involving simultaneous damage to three structures: the anterior cruciate ligament, medial meniscus, and tibial collateral ligament, often resulting from a twisting force to the knee.

How is the knee joint supplied with blood and nerves?

Blood supply comes from the genicular anastomosis, involving branches from the popliteal, femoral, and other arteries. Nerve supply includes the femoral, obturator, tibial, and common peroneal nerves, which provide sensory and motor innervation to the joint.

What are some common clinical conditions affecting the knee?

Common knee conditions include osteoarthritis, causing degenerative pain and limited movement; meniscal tears, often in the medial meniscus due to its fixity; and bursitis (e.g., Housemaid's knee from kneeling) and Baker's cyst in the popliteal fossa.

Knee Joint – Ligaments, Menisci & Injuries

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