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The intercondylar eminence is a small section of bone that protrudes from the top of the tibia in the leg. Found within the knee joint, this bony feature projects upward from the top central surface of the tibia between the medial and lateral condyles, the two large, rounded sections that form the superior or upper end of the bone. The intercondylar eminence sits between the attachment sites for the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). It is a common site of bone fracture in children and adolescents, often as a consequence of falling from a motorbike or bicycle.
As the larger of the two shin bones, the tibia forms the knee joint with the bottom end of the femur, or thigh bone. Between the end of the femur and the top of the tibia, a surface often referred to as the tibial plateau, is a fluid-filled sac called the joint capsule. Within this capsule are the two menisci, flattened disks of cartilage separating the bones from much direct contact with one another, and several ligaments joining the bones together. The most prominent of these are the ACL and PCL, which when viewed from the front appear to form an X between the femur and tibia.
Both cruciate ligaments originate on the underside of the femur between its medial and lateral condyles. The ACL arises from the lateral or outside condyle and from within the fibular notch, which is the indentation between the condyles, while the PCL behind it attaches to the medial or inside condyle. Though they are surrounded by the capsule of the knee joint, they are not actually contained within the capsule but sectioned off by the capsule’s synovial membrane, giving the capsule a doughnut shape with the ligaments passing through the hole in the center.
At the bottom of the joint, the two cruciate ligaments angle toward the center of the tibial plateau from their respective condyles. The PCL inserts along an area immediately behind the intercondylar eminence known as the posterior intercondylar area. This is a rough, flattened surface in the center of the top of the tibia that is located toward the rear side of the bone.
Conversely, the ACL veers toward the front side of the intercondylar eminence, where it attaches to the center of the bone. The intercondylar eminence itself forms the protruding bony section between the articular facets atop the condyles, which are simply the large shallow depressions where the lateral and medial condyles of the lower femur rest against their respective condyles on the upper tibia. Features of the eminence include a pair of tubercles, or upward-pointing projections flanking either side of the eminence that insert into the fibular notch when the knee is straightened. These tubercles can fracture from the bone, usually when an excessive force on the knee joint as sustained during an impact causes the ACL to yank away from the tibia, tearing the intercondylar eminence from the tibial plateau.