KNEE

The knee joint can be described as a hinging or hinged joint (between the femur and tibia) and flat (between the femur and patella).

The bones of the knee joint are joined by the following structures:

Articular Capsule & #8211; It consists of a thin but resilient fibrous membrane, reinforced to almost its full extent by ligaments closely adhered to it. Below the femoral quadriceps tendon the capsule is represented only by the synovial membrane.

Patellar Ligament & #8211; It is the central portion of the femoral quadriceps tendon that continues from the patella to the tibial tuberosity. It is a strong, flattened ligamentous beam about 8 cm long. The posterior surface of the patellar ligament is separated from the synovial membrane by a large infra-patellar fat pad and from the tibia by a synovial pouch.

Oblique Popliteal Ligament & #8211; It is a fibrous bundle, broad and flat, formed by fascicles separated from each other. It forms part of the floor of the popliteal fossa.

Arched Popliteal Ligament & #8211; It forms an arc from the lateral condyle of the femur to the posterior surface of the joint capsule. It is joined to the styloid process of the fibular head by six converging beams.

Tibial Collateral Ligament & #8211; It is a broad, flattened membranous bundle that extends to the back of the joint. It is inserted into the medial condyle of the femur and the medial condyle of the tibia. It is closely adherent to the medial meniscus. Prevents the movement away from the medial condyles of the femur and tibia (medial yawning).

Fibular Collateral Ligament & #8211; It is a strong, rounded fibrous cord inserted into the lateral condyle of the femur and the head of the fibula. It does not fit into the lateral meniscus. Prevents the movement away from the lateral condyles of the femur and tibia (lateral yawning).

Anterior Cruciate Ligament (ACL) & #8211; It fits into the intercondylar eminence of the tibia and will attach to the medial face of the lateral femoral condyle. The ACL has a relatively scarce blood supply. Prevents the anterior sliding movement of the tibia or posterior sliding of the femur (anterior drawer movement), as well as knee hypertension.

Posterior Cruciate Ligament (PCL) & #8211; It is more robust but shorter and less oblique in its direction when compared to the ACL. It is inserted into the posterior intercondylar fossa of the tibia and posterior end of the lateral meniscus and is directed forward and medially to fixate on the anterior part of the medial face of the femoral medial condyle. The PCL is stretched during knee joint flexion. Prevents posterior sliding movement of the tibia or anterior displacement of the femur (Posterior Drawer Movement).

In addition to the ligaments, the knee also has another very important structure in its stabilization, biomechanics and impact absorption: the menisci. The menisci are two crescent-shaped blades that serve to deepen the surfaces of the articular faces of the tibial head that receive the femoral condyles. Each meniscus covers approximately two peripheral thirds of the corresponding articular face of the tibia.

Medial Meniscus & #8211; It is almost semi-circular in shape, slightly elongated and wider posteriorly. Its anterior extremity attaches to the anterior intercondylar fossa of the tibia and the posterior end to the posterior intercondylar fossa of the tibia.

Lateral Meniscus & #8211; It is almost circular and covers a greater extension of the articular face than that covered by the medial meniscus. Its anterior extremity attaches to the anterior intercondylar eminence of the tibia and the posterior end to the intercondylar eminence of the tibia.

Transverse Ligament & #8211; joins the anterior convex margin of the lateral meniscus to the anterior end of the medial meniscus. Sometimes it is absent.

Coronary Ligaments & #8211; They are portions of the capsule that join the periphery of the menisci with the margin of the tibial head.

Distal to the knee joint and still in the proximal portions of the fibula and tibia, we find another important joint: the Proximal Tibio-fibular Joint.

It is a sliding joint between the lateral tibial condyle and the fibular head. It is formed by an articular capsule and the anterior and posterior ligaments.

Articular Capsule & #8211; It surrounds the joint and adheres around the margins of the articular facets of the tibia and fibula.

Anterior Ligament & #8211; It consists of 2 or 3 broad and flat beams that run obliquely from the fibular head to the anterior part of the lateral tibial condyle.

Posterior Ligament & #8211; It is a single, broad and thick beam that runs obliquely upwards from the posterior part of the fibular head to the posterior part of the lateral tibial condyle.

PREVIOUS VIEW OF THE KNEE JOINT STRUCTURES
 Anterior View of Knee Joint Structures
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
REAR VIEW OF THE KNEE JOINT STRUCTURES
Posterior View of Knee Joint Structures
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
TOP VIEW OF KNEE JOINT STRUCTURES
 Upper View of Knee Joint Structures
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

 

SEE MORE

Synovial Joints
ATM
Spine
Shoulder
Elbow
Fist
Hip
Ankle