The lateral collateral ligament (LCL, long external lateral ligament or fibular collateral ligament) is a

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal l ...

located on the

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...

(outer) side 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 ...

, and thus belongs to the extrinsic knee ligaments and

posterolateral corner Posterolateral corner injuries (PLC injuries) of the knee are injuries to a complex area formed by the interaction of multiple structures. Injuries to the posterolateral corner can be debilitating to the person and require recognition and treatment ...

of the knee.

Structure

Rounded, more narrow and less broad than the

medial collateral ligament The medial collateral ligament (MCL), or tibial collateral ligament (TCL), is one of the four major ligaments of the knee. It is on the medial (inner) side of the knee joint in humans and other primates. Its primary function is to resist outwar ...

, the lateral collateral ligament stretches obliquely downward and backward from the lateral epicondyle 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 ...

above, to the head of the fibula below. In contrast to the medial collateral ligament, it is fused with neither the capsular ligament nor the

lateral meniscus The lateral meniscus (external semilunar fibrocartilage) is a fibrocartilaginous band that spans the lateral side of the interior of the knee joint. It is one of two menisci of the knee, the other being the medial meniscus. It is nearly circular ...

. Because of this, the lateral collateral ligament is more flexible than its medial counterpart, and is therefore less susceptible to injury. Both collateral ligaments are taut when the knee joint is in extension. With the knee in flexion, the radius of curvatures of the

condyle A condyle (;Entry "condyle"
in
coronal plane The coronal plane (also known as the frontal plane) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes. Details The coronal plane is an example of a longitud ...

. Therefore, damage and rupture of these ligaments can be diagnosed by examining the knee's mediolateral (side) stability. Immediately below its origin is the groove for the tendon of the popliteus. The greater part of its lateral surface is covered by the tendon of the

biceps femoris The biceps femoris () is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group. Structure It has two heads of origin: *the ''long ...

; the tendon, however, divides at its insertion into two parts, which are separated by the ligament. Deep to the ligament are the tendon of the popliteus, and the inferior lateral genicular vessels and nerve.

Causes of injury

The LCL is usually injured as a result of varus force across the knee, which is a force pushing the knee from the medial (inner) side of the joint, causing stress on the outside. An example of this would be a direct blow to the inside of the knee. The LCL can also be injured by a noncontact injury, such as a hyperextension stress, again causing varus force across the knee. An LCL injury usually occurs simultaneously as the other ligaments of the knee are injured. Multiple knee ligament tears and stresses can result from a significant trauma that includes direct blunt force to the knee, such as an automobile crash.

Symptoms

Symptoms of a sprain or tear of the LCL includes pain to the lateral aspect of the knee, instability of the knee when walking, swelling and ecchymosis (bruising) at the site of trauma. Direct trauma to the medial aspect of the knee may also affect the peroneal nerve, which could result in a foot drop or paresthesias below the knee which could present itself as a tingling sensation.

Treatment

An isolated LCL tear or sprain rarely requires surgery. If the injury is a Grade 1 or Grade II, microscopic or partial macroscopic tearing respectively, the injury is treated with rest and rehabilitation. Ice, electrical stimulation and elevation are all methods to reduce the pain and swelling felt in the initial stages after the injury takes place. Physical therapy focuses on regaining full range-of-motion, such as biking, stretching and careful applications of pressure on the joint. Full recovery of Grade I or Grade II tears should take between 6 weeks and 3 months. Continued pain, swelling and instability to the joint after this time period may require surgical repair or reconstruction to the ligament.

Additional images

File:Gray352.png, Capsule of right knee-joint (distended). Posterior aspect. File:Slide2CAC.JPG, Anterior view of knee.

References

External links

* () {{DEFAULTSORT:Fibular Collateral Ligament Knee ligaments