Generality
The ligaments of the knee are the bands of connective-fibrous tissue, which join the distal end of the femur to the proximal end of the tibia.
There are a total of 4 knee ligaments: the anterior cruciate ligament, the posterior cruciate ligament, the medial cruciate ligament and the lateral cruciate ligament.
The task of the knee ligaments is to stabilize the articulation of which they are a part and to prevent the bony components of this joint from losing their correct alignment.
The ligaments of the knee can be subject to strains and lacerations, which, if particularly serious, can compromise the health of other joint components.
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 ; opposite to the femur, it participates in the knee joint with its proximal end.
Finally, the kneecap is a 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 an insertion site for the quadriceps muscle tendons and provides protection to the articular elements of the knee, located behind her.
Thanks to the strategic position and the aforementioned 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?
The synovial joints, or diarthrosis, are extremely mobile joints, which include various components, including: the articular surfaces and the cartilage that covers them, the joint capsule, the synovial membrane, the synovial bags and a series of ligaments and tendons.
Figure: the knee represents the intermediate articulation of the lower limb.
At its formation, the two condyles of the distal end of the femur, the two condyles and the so-called tibial plateau, belonging to the proximal end of the tibia, and finally the entire patella participate.
What are knee ligaments?
The ligaments of the knee are the bands of connective-fibrous tissue, which hold the distal end of the femur at the proximal end of the tibia.
Review of the meaning of the terms proximal and distal
Proximal and distal are two terms with opposite meaning.
Proximal means "closer to the center of the body" or "closer to the point of origin". Referring to the femur, for example, it indicates the portion of this bone closest to the trunk.
Distal, on the other hand, means "farther from the center of the body" or "farther from the point of origin". Referred (always to the femur), for example, it indicates the portion of this bone furthest from the trunk (and closer to the trunk). 'knee joint).
Anatomy
There are a total of 4 knee ligaments: the two cruciate ligaments, anterior and posterior, and the two collateral ligaments, medial and lateral .
The two cruciate ligaments of the knee run from the lower surface of the distal end of the femur to the upper surface of the proximal end of the tibia.
The two collateral ligaments of the knee, on the other hand, originate from the outer and inner side surfaces of the distal end of the femur and terminate one on the lateral surface of the distal end of the tibia and one on the so-called fibula head.
The next four sub-chapters will describe each knee ligament in more detail.
In anatomy, medial and lateral are two terms of opposite meaning, which serve to indicate the distance of an anatomical element from the sagittal plane . The sagittal plane is the anteroposterior division of the human body, from which two equal and symmetrical halves are derived.
Mediale means "near" or "closer" to the sagittal plane, while lateral means "far or" farther "from the sagittal plane.
FRONT CRUCIO LIGATURE
The anterior cruciate ligament originates in an area of the lower surface of the distal end of the femur, between the so-called intercondylar fossa (or intercondylar fossa ) and the so-called lateral condyle .
From here, it reaches the upper surface of the distal end of the tibia and engages a bony prominence known as anterior intercondylar tubercle.
The anterior intercondylar tubercle is a particular portion of the so-called tibial plate, that is, the concave area, similar to a kitchen dish, resulting from the particular morphology of the medial condyle and the lateral condyle of the tibia .
Figure: knee ligaments and their bone insertions.
REAR CRUCED BINDING
The posterior cruciate ligament originates in an area of the lower surface of the distal end of the femur, between the aforementioned intercondylar fossa and the so-called medial condyle .
From here, it reaches the upper surface of the proximal end of the tibia and attaches to a bony prominence called the posterior intercondylar tubercle . The posterior intercondylar tubercle is located on the tibial plateau, exactly like the anterior intercondylar tubercle, but unlike the latter it takes place in a more backward position.
MEDIUM SIDE BONDAGE
The medial collateral ligament is the knee ligament located on the inner side of the latter, which is born at the height of the so-called medial epicondyle of the femur and ends at the aforementioned medial condyle of the tibia.
The medial collateral ligament is also known as the internal collateral ligament, as it takes place, in effect, on the inner side of the knee.
SIDE COLLATERAL BOND
The lateral collateral ligament is the knee ligament located on the outer side of the latter, which is born at the height of the so-called lateral epicondyle of the femur and ends at the aforementioned fibula head .
The involvement of the fibula must not lead readers to consider this bone as a component of the knee joint. In fact, beyond accommodating the terminal head of the lateral collateral ligament, the fibula does not communicate in any way with the femur and does not support at all the weight that the femur unloads on the tibia.
The lateral collateral ligament is also known as the external collateral ligament, as it actually resides on the outer side of the knee.
Function
The knee ligaments have the task of stabilizing the knee joint and ensuring the alignment of the bony components of the latter, during any type of movement of the lower limb.
Without its ligaments, the knee would become the protagonist of excessive movements, out of the norm, which could cause damage to the bony portions involved in the joint.
Going into more detail:
- The medial collateral ligament strengthens the inner side of the knee and prevents excessive thrust on the opposite side from misaligning the femur in relation to the tibia or tibia in relation to the femur.
- The lateral collateral ligament has the same function as the medial collateral ligament, with the only difference residing on the opposite side. Then, it strengthens the outer side of the knee and prevents excessive thrusts on the opposite side from causing the misalignment, in a lateral direction, of the femur with respect to the tibia or of the tibia with respect to the femur.
- The anterior cruciate ligament prevents hyperextension of the knee, limiting excessive forward movement of the tibia.
- The posterior cruciate ligament prevents the excessive sliding forward of the femur, with respect to the tibia, and, at the same time, the excessive sliding backwards of the tibia, with respect to the femur.
In essence, therefore, 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.
clinic
The knee is an articulation that lends itself easily to being the victim of injuries - the so-called sprains - in which one or more ligaments of the knee can undergo stretching or real lacerations .
In general, injuries to the ligaments of the knee have a traumatic origin, ie they arise following a trauma; the categories most at risk are surely sportsmen and the elderly.
When the ligaments of the knee are subject to stretching, or in the worst hypothesis of lacerations, their ability to fulfill the stabilizing function and alignment of the various bone components, forming the knee joint, is compromised. This can lead to various complications, including: rupture of the meniscus, inflammation of some synovial bursa and / or degeneration due to rubbing of articular cartilage .
According to reliable clinical studies, the most serious injuries to the knee ligaments are a predisposing factor for osteoarthritis of the knee.
