The lateral meniscus (external semilunar fibrocartilage) is a

fibrocartilaginous Fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its inflexibility and toughness to the former of these constituents, and its Elasticity (physics), elasticity to the latter. It ...

band that spans the lateral side of the interior of the

knee In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

joint. It is one of two menisci of the knee, the other being the

medial meniscus The medial meniscus is a fibrocartilage semicircular band that spans the knee joint medially, located between the medial condyle of the femur and the medial condyle of the tibia.Platzer (2004), p 208 It is also referred to as the internal semilun ...

. It is nearly circular and covers a larger portion of the articular surface than the medial. It can occasionally be injured or torn by twisting the knee or applying direct force, as seen in

contact sport Contact sports are sports that emphasize or require physical contact between players. Some sports, such as mixed martial arts, are scored on impacting an opponent, while others, including rugby football, gridiron football and Australian rules fo ...

Structure

The lateral meniscus is grooved laterally for the tendon of the

popliteus The popliteus muscle in the leg is used for unlocking the knees when walking, by laterally rotating the femur on the tibia during the closed chain portion of the gait cycle (one with the foot in contact with the ground). In open chain movements ...

, which separates it from the

fibular collateral ligament The lateral collateral ligament (LCL, long external lateral ligament or fibular collateral ligament) is a ligament located on the lateral (outer) side of the knee, and thus belongs to the extrinsic knee ligaments and posterolateral corner of the k ...

. Its anterior end is attached in front of the intercondyloid eminence of the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

, lateral to, and behind, the

anterior cruciate ligament The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. The two ligaments are also called "cruciform" ligaments, as they are arranged in a crossed formation ...

, with which it blends; the posterior end is attached behind the intercondyloid eminence of the tibia and in front of the posterior end of the medial meniscus. The anterior attachment of the lateral meniscus is twisted on itself so that its free margin looks backward and upward, its anterior end resting on a sloping shelf of bone on the front of the lateral process of the

intercondyloid eminence The intercondylar area is the separation between the medial and lateral condyle on the upper extremity of the tibia. The anterior and posterior cruciate ligaments and the menisci attach to the intercondylar area. The intercondyloid eminence is ...

. Close to its posterior attachment it sends off a strong

fasciculus ''Fasciculus vesanus'' is an extinct species of stem-group ctenophores known from the Burgess Shale of British Columbia, Canada. It is dated to and belongs to middle Cambrian strata. The species is remarkable for its two sets of long and short ...

, the ligament of

Wrisberg Heinrich August Wrisberg (20 June 1739 – 29 March 1808) was an anatomist. He also published under the Latinized version of his name as Henricus Augustus Wrisberg. Education He obtained his MD in 1763 at the University of Göttingen with a thes ...

, which passes upward and medialward, to be inserted into the medial condyle of the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

, immediately behind the attachment of the

posterior cruciate ligament The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the medial cond ...

. The lateral meniscus gives off from its anterior convex margin a fasciculus which forms the transverse ligament.

Variation

Occasionally a small fasciculus passes forward to be inserted into the lateral part of the

Clinical significance

The lateral meniscus is less likely to be injured or torn than the medial meniscus. Diagnosis of lateral meniscus tear is done with

McMurray's test The McMurray test, also known as the McMurray circumduction test is used to evaluate individuals for tears in the meniscus of the knee. A tear in the meniscus may cause a pedunculated tag of the meniscus which may become jammed between the joint sur ...

. If a tear is detected, treatment depends on the type and size of the tear. Small tears can be treated conservatively, with rest, ice, and pain medications until the pain is under control, then exercise may be started with gradually increasing intensity, to improve range of motion and decrease swelling. More severe tears of the lateral meniscus require surgical repair or removal, which can often be done

arthroscopically Arthroscopy (also called arthroscopic or keyhole surgery) is a minimally invasive surgical procedure on a joint in which an examination and sometimes treatment of damage is performed using an arthroscope, an endoscope that is inserted into the j ...

. Swelling and stiffness of the knee can occur when you have a torn lateral meniscus.

Additional images

File:Gray348.png, Left

joint from behind, showing interior ligaments. File:Gray347.png, Right knee-joint, from the front, showing interior ligaments. File:Gray351.png, Capsule of right knee-joint (distended). Lateral aspect. File:Gray352.png, Capsule of right knee-joint (distended). Posterior aspect. File:Slide2CAC.JPG, Anterior view of knee. File:Slide2bib.JPG, Right knee in extension. Deep dissection. Posterior view. File:Slide2cocc.JPG, Right knee in extension. Deep dissection. Posterior view. File:Slide1besa.JPG, Knee and tibiofibular joint.Deep dissection. Anterior view. File:Slide2besa.JPG, Knee and tibiofibular joint.Deep dissection. Anterior view. File:Slide1wewe.JPG, Knee joint.Deep dissection. Anteromedial view. File:Slide2wewew.JPG, Knee joint.Deep dissection. Anteromedial view. File:Slide3wewe.JPG, Knee joint.Deep dissection. Anteromedial view. File:Slide4wewe.JPG, Knee joint.Deep dissection. Anteromedial view. File:Slide3ecce.JPG, Knee joint. Deep dissection. Anterior view File:Slide1dada.JPG, Knee joint. Deep dissection. Anterior view. File:Slide3dada.JPG, Knee joint. Deep dissection. Posterior view

References

External links