Generality
The anterior cruciate ligament is a fundamental ligament of the knee joint.
About 30 millimeters long on average and 11 millimeters wide on average, the anterior cruciate ligament is born on the inferior surface of the distal end of the femur (to be precise, in the area of the intercondylar fossa near the lateral condyle of the femur) and ends on the upper surface of the proximal end of the tibia (to be exact, in the anterior intercondylar fossa of the tibial plateau).
Crossed with the posterior cruciate ligament (another fundamental knee ligament), the anterior cruciate ligament covers two important functions: it prevents hyperextension of the knee and limits the internal rotation of the tibia.
Following a knee sprain, the anterior cruciate ligament may be subject to tearing; the laceration of the anterior cruciate ligament requires the use of reconstructive surgery, as the ligament in question does not heal spontaneously.
What is the Anterior Cruciate Ligament?
The anterior cruciate ligament is one of the two ligaments of the knee (the other is the posterior cruciate ligament ) which run from the lower surface of the femur to the upper surface of the tibia .
The anterior cruciate ligament is a fundamental ligament of the knee, just like the aforementioned posterior cruciate ligament, the internal collateral ligament (or medial collateral ligament) and the external collateral ligament (or lateral collateral ligament).
Also known by the acronym LCA, the anterior cruciate ligament owes its name to the fact that, during the junction of the tibia, it crosses with the posterior cruciate ligament ("cruciate"), passing in front of it ("anterior").
What is a ligament?
A ligament is a band of fibrous connective tissue, with a certain flexibility and a high content of collagen, which connects two bones or two distinct parts of the same bone.
In the specific case of the anterior cruciate ligament, the latter is a ligament placed between two distinct bones.
Short anatomical reference of the knee
The knee is one of the most important synovial joints in the human body.
Less known as an tibiofemoral joint, the knee joins three bones: the femur, the tibia and the patella .
- The femur is the bone of the thigh ; participates in the knee joint with its distal end.
- The tibia is the bone which, together with the fibula, constitutes the skeleton of the leg ; located inferiorly to the femur (if one imagines looking at a human body in an upright position), it contributes to the knee joint with its proximal end.
- Finally, the kneecap is the triangular-shaped bone that, placed in front of the femur and tibia, forms the classic protrusion visible in the anterior part of the knee; the patella is the site of insertion for the quadriceps muscle tendons and the patellar tendon, and guarantees protection to the articular elements of the knee, located posteriorly.
Thanks to its strategic position and its structural components, the two knees play a fundamental role in supporting the weight of the body and in allowing the movements of the lower limbs, which are at the base of walking, running, jumping, etc.
What is a synovial joint?
Synovial joints - such as the knee - are extremely mobile joints, which include various components, including: the fibrous cartilage that covers the surfaces of the bones involved, the joint capsule, the synovial membrane, the synovial bags and a series of ligaments and tendons.
Anatomy
The anterior cruciate ligament is a band of fibrous tissue that arises from the lower surface of the femur and ends at the lower surface of the tibia.
Located inside the knee, the anterior cruciate ligament follows a particular path, which leads it to cross with the posterior cruciate ligament and to place itself in front of it.
Dimensions of the Anterior Cruciate Ligament
The anterior cruciate ligament has an average length of 30 millimeters (3 centimeters) and an average diameter of 11 millimeters (1.1 centimeters).
Despite its small size, the anterior cruciate ligament is essential for the proper functioning of the knee and for the long-term well-being of the joint itself.
Origin of the Anterior Crusader Ligament
To understand: review of the proximal-distal terms
" Proximal " means "closer to the center of the body" or "closer to the point of origin"; " distal ", instead, means "farther from the center of the body" or "farther from the point of origin.
Examples:
- The femur is proximal to the tibia, which is distal to the femur.
- In the femur, the extremity bordering the trunk is the proximal end, while the extremity bordering the knee is the distal end.
The anterior cruciate ligament originates from the lower surface of the distal end of the femur; to be precise, it arises from the intercondylar fossa of the distal end of the femur, in an area of this fossa very close to the lateral condyle (of the femur).
The lateral (or external) condyle and the medial (or internal) condyle of the femur are the two particular prominences that constitute the terminal part of the distal end of the femur.
Below (ie on the lower surface of the femur), these two prominences are separated by a depression: the aforementioned intercondylar femoral fossa.
On the intercondylar fossa two zones are recognizable: one external, near the lateral condyle, from which the anterior cruciate ligament originates, and one internal, near the medial condyle, which emits the posterior cruciate ligament.
Terminal insertion of the Lower Crusader Ligament
The anterior cruciate ligament terminates its path on the upper surface of the proximal end of the tibia; to be precise, he ends his journey just ahead of the anterior intercondylar fossa of the tibial plateau, near the anterior horn of the medial meniscus .
The tibial plateau is the characteristic structure present on the upper surface of the tibia.
Separated from the anterior intercondylar fossa, anteriorly, and from the intercondylar fossa, posteriorly, the tibial plateau houses the medial meniscus, the lateral meniscus, the terminal head of the anterior cruciate ligament (on the anterior intercondylar fossa) and the terminal head of the posterior cruciate ligament (on posterior intercondylar fossa).
Course of the Anterior Crusader Ligament: a few more details
In light of what has been stated regarding the origin and conclusion of the anterior cruciate ligament, the latter, in going from the femur to the tibia, takes a slightly oblique path with medial orientation: its terminal head present on the tibia, in fact, is more medial than his initial head on the femur.
Brief review of the medial-lateral terms
Recalling that the sagittal plane is the anteroposterior division of the human body from which two equal and symmetrical halves are derived, " medial " means "near" or "closer" to the sagittal plane, while " lateral " means "far" or " farther "from the sagittal plane.
Example to understand:
- The second toe is lateral to the big toe, but is medial to the third toe.
Vascularization
The anterior cruciate ligament is not vascularized .
The lack of vascularization makes it impossible for the anterior cruciate ligament to heal spontaneously if it suffers a partial or total lesion of its connective bundles.
Readers are reminded that it is oxygen and nutrients in the blood that allow healing of the tissues that are the victims of injuries, injuries, etc.
Comparison with the Posterior Cruciate Ligament
- The posterior cruciate ligament arises from the intercondylar fossa of the distal end of the femur, in an area of this fossa very close to the medial condyle; the anterior cruciate ligament, instead, is born in an area of the intercondylar fossa of the femur near the lateral condyle (of the femur).
- The posterior cruciate ligament ends its path by inserting itself on the posterior intercondylar fossa of the tibial plateau, near the posterior horn of the medial meniscus; the anterior cruciate ligament, on the other hand, concludes its journey on the anterior intercondylar fossa of the tibial plateau, in the vicinity of the anterior horn of the medial meniscus.
- The posterior cruciate ligament performs an oblique path, with lateral orientation: exactly the opposite of what happens for the anterior cruciate ligament, in fact, its terminal head present on the tibia is more lateral than its initial head present on the femur.
Function
Together with the other three basic ligaments of the knee, the anterior cruciate ligament helps to stabilize the knee and to guarantee the alignment of the bony components of this important joint, during any type of movement of the lower limb.
Without the anterior cruciate ligament and the other 3 fundamental ligaments, the knee would become the protagonist of excessive, abnormal, uncontrolled movements, which could cause damage to the portions of the femur and tibia involved in the joint.
In general, the cruciate ligaments control the stresses along the antero-posterior axis of the knee, while the collateral ligaments moderate the stresses in a lateral and medial direction.
Specific Functions of the Anterior Cruciate Ligament
Specifically, the anterior cruciate ligament covers two important functions:
- Prevent hyperextension of the knee, limiting excessive forward movement of the tibia, e
- Limit internal rotation of the tibia .
Furthermore, some studies have shown that the anterior cruciate ligament would be equipped with mechanoreceptors, capable of detecting changes in direction during movement, the position of the knee and changes in speed during movement.
As stated in a previous passage of this article, the anterior cruciate ligament is essential not only for the proper functioning of the knee, but also for its long-term well - being ; in fact, people who have suffered multiple injuries to the anterior cruciate ligament or have not done the injury promptly are more at risk of knee osteoarthritis (or gonarthrosis ).
diseases
Following a knee sprain, the anterior cruciate ligament can be the subject of laceration .
Tearing of the anterior cruciate ligament is the condition best known as anterior cruciate ligament rupture .
What is a knee sprain?
Knee sprains are acute events, in which the joint in question undergoes, following an unnatural movement or a sudden trauma, a temporary modification in anatomy, which leads to damage to its constituent elements (lesions of the medial or lateral meniscus, stretching of collateral ligaments, etc.).
Anterior Cruciate Ligament Rupture: What is it?
The rupture of the anterior cruciate ligament is a serious injury to the knee, which jeopardizes the stability of the joint in an important way and jeopardizes its functioning, making activities such as running, jumping etc. impossible.
In people who are young or in any case active, anterior cruciate ligament rupture makes it necessary to resort to surgery with the aim of reconstructing the injured structure (reconstructive surgery); surgery is the only solution available at the moment, as the anterior cruciate ligament cannot repair itself autonomously due to the absence of a blood supply to it.
A person who is a victim of anterior cruciate ligament rupture is severely limited in movements with the affected lower limb.
