🥇 ARTICULACION DE LA RODILLA. ¡Explicación Sencilla!

Introduction to the Knee Joint

In this section, the speaker introduces the topic of the knee joint and invites viewers to subscribe to their anatomy channel. They mention that the knee joint is one of the most complicated joints in the human body.

Surface Articulations of the Knee Joint

• The knee joint is a triple articulation with complex shapes and multiple articular elements.

• The classification and description of the knee joint may vary in different anatomy books, but they all cover similar content.

• The speaker will focus on five main points in this video: surface articulations, menisci, ligaments, synovial membrane, and movements of the joint.

Surface Articulations

• The knee joint is classified as a special bicondylar joint due to its unique movements beyond those of normal bicondylar joints.

• It was previously referred to as a trochlear or hinge joint, but it is now recognized as a special bicondylar joint with additional movements.

• The superior surface articulation is formed by condyles of the femur covered with hyaline cartilage.

• The tibial surface articulation consists of two large condylar cavities covered with hyaline cartilage.

• The patella (kneecap) has two articular surfaces that articulate with each femoral condyle.

Components of the Knee Joint

This section focuses on discussing the components of the knee joint, including menisci and their structure.

Menisci

• Menisci are fibrocartilaginous structures located within the knee joint.

• They are intraarticular structures and cannot be seen from outside.

• When viewed sagittally, menisci appear triangular in shape with a wider outer surface and a narrower inner surface.

• The outer part of the meniscus articulates with the fibrous ligaments of the joint capsule.

Surface Articulations and Menisci

This section provides a visual explanation of the surface articulations of the knee joint and the structure of menisci.

Surface Articulations

• The femur's condyles and tibial glenoid surfaces form the surface articulations of the knee joint.

• The femoral condyles have two articular surfaces, while each tibial glenoid has one articular surface for articulation with the patella.

Menisci Structure

• Menisci are triangular structures within the knee joint.

• They have a wider outer surface and a narrower inner surface.

• The outer part of each meniscus articulates with fibrous ligaments in the joint capsule.

Conclusion

In this final section, the speaker concludes by emphasizing that understanding the knee joint can be challenging due to its complex anatomy. However, they aim to provide a concise and precise explanation in their videos.

Recap

• The incongruent nature of the knee joint's surface articulations makes it unique among synovial joints.

• Menisci are important intraarticular structures that cannot be seen externally. They have a triangular shape with wider outer surfaces and narrower inner surfaces.

Timestamps may not align perfectly due to differences in video versions or minor variations in speech speed.

New Section

This section discusses the importance of subscribing to the channel and introduces the topic of meniscus in the knee joint.

Introduction and Subscription

• It is vital to like and subscribe to the videos.

• Subscribing to the channel helps stay updated with new content.

Understanding Meniscus in the Knee Joint

• The knee joint has two menisci: external (lateral) and internal (medial).

• The menisci help deepen the glenoid cavity of the tibia, which is necessary due to the size difference between the femur and tibia.

• The menisci also serve as surfaces for cushioning and lubrication in weight-bearing activities.

• People with meniscus pathologies often experience difficulty walking.

New Section

This section provides further details about the structure and functions of the menisci in relation to knee joint articulation.

Structure of Menisci

• Each meniscus has two faces: superior face towards femur, inferior face towards tibia.

• They have an outer circumference where the fibrous capsule of the joint attaches.

• They also have inner circumferences known as horns that attach them firmly to the tibia.

New Section

This section explains how each meniscus differs from one another and their specific insertions on both anterior and posterior sides.

Difference Between External (Lateral) Meniscus and Internal (Medial) Meniscus

External (Lateral) Meniscus

• Smaller circumference compared to internal meniscus.

• Almost a complete circle shape, resembling "o."

• Anterior horn inserts into intercondylar anterior zone on tibia.

• Posterior horn inserts into medial intercondylar tubercle.

Internal (Medial) Meniscus

• Longer in the anteroposterior direction.

• Described as having a shape resembling "C" with lateral concavity.

• Anterior horn inserts at the anterior edge of the tibial plateau.

• Posterior horn inserts into intercondylar posterior zone.

New Section

This section provides a mnemonic to remember the difference between external and internal menisci, along with a top view of the tibia and their insertions.

Mnemonic for Remembering External and Internal Menisci

• Mnemonic: "OS" - O for external (lateral), S for internal (medial).

• External meniscus has a shape almost like "o," while internal meniscus has a shape resembling "s."

New Section

This section discusses the joint capsule and its structure around the knee joint, including its separation from cartilaginous parts.

Joint Capsule Structure

• The joint capsule surrounds the knee joint, forming a true cuff-like structure.

• The upper part of the capsule separates from cartilaginous parts by 0.5 to 1.5 centimeters.

• The lower part of the capsule is close to the tibial plateau, separated by only 0.2 to 0.3 centimeters.

Conclusion

The transcript provides an overview of menisci in the knee joint, discussing their structure, functions, and specific insertions on both anterior and posterior sides. It also explains how each meniscus differs from one another and provides mnemonics to remember their characteristics. Additionally, it briefly mentions the structure of the joint capsule surrounding the knee joint.

Structure of the Knee Joint

In this section, the speaker explains the structure of the knee joint and its different components.

Components of the Knee Joint

• The knee joint consists of two menisci, with the inner part being free and the outer part adhering to them.

• There are two zones in relation to these menisci: a wide zone above called supra meniscus and a shorter zone below called infra meniscus.

• The anterior part of the joint is supported by the patellar ligament, which is an extension of the quadriceps tendon.

Ligaments and Bursae

• The anterior region of the knee has two flaps or wings known as medial and lateral flaps.

• These flaps, along with the patellar ligament, reinforce the anterior capsule of the joint.

• Bursae are fluid-filled sacs found in various locations around the knee. Three important bursae are mentioned:

• Prepatellar bursa (in front of the patella)

• Superficial infrapatellar bursa (below the patella in relation to the patellar ligament)

• Deep infrapatellar bursa (also below the patella but deeper)

• There is also an intraarticular ligament that connects both menisci in their anterior part. It is called transverse ligament or transverse meniscal ligament.

Posterior Ligaments

• The posterior part of the knee joint is reinforced by two ligaments:

• Popliteal oblique ligament (an extension of semimembranosus muscle)

• Arcuate popliteal ligament (wraps around posterior muscles)

Cruciate Ligaments

• Cruciate ligaments play a crucial role in stabilizing the knee joint.

• There are two cruciate ligaments that cross each other in a transverse and anteroposterior direction:

• Anterior cruciate ligament (ACL)

• Posterior cruciate ligament (PCL)

• The names "anterior" and "posterior" refer to their insertion points on the tibia.

Lateral Ligaments

• The lateral aspect of the knee joint is reinforced by two ligaments:

• Medial collateral ligament (MCL) or tibial collateral ligament

• Lateral collateral ligament (LCL) or fibular collateral ligament

Summary of Knee Joint Ligaments

In this section, the speaker provides a summary of the different ligaments that reinforce the knee joint.

Cruciate Ligaments

• Cruciate ligaments are important for stabilizing the knee joint.

• There are two cruciate ligaments that cross each other in a transverse and anteroposterior direction:

• Anterior cruciate ligament (ACL)

• Originates posteriorly in relation to its insertion on the tibia

• Crosses behind the posterior cruciate ligament

• Posterior cruciate ligament (PCL)

• Originates anteriorly in relation to its insertion on the tibia

• Crosses in front of the anterior cruciate ligament

Lateral Ligaments

• The lateral aspect of the knee joint is reinforced by two ligaments:

• Medial collateral ligament (MCL) or tibial collateral ligament

• Extends from medial condyle of femur to medial surface of tibia

• Lateral collateral ligament (LCL) or fibular collateral ligament

• Extends from lateral condyle of femur to head of fibula

Conclusion and Intraarticular Ligaments

In this section, the speaker concludes the discussion on knee joint ligaments and mentions intraarticular ligaments.

Conclusion of Ligament Discussion

• The posterior cruciate ligament inserts in the posterior intercondylar area of the tibia, while the anterior cruciate ligament inserts in the anterior intercondylar area.

• The names "anterior" and "posterior" refer to their insertion points on the tibia.

Intraarticular Ligament

• There is an intraarticular ligament that can pass behind or in front of the menisci:

• Posterior meniscofemoral ligament (when passing behind)

• Anterior meniscofemoral ligament (when passing in front)

• These ligaments connect the femur with the external meniscus.

This summary provides an overview of key points discussed in the transcript. For a more detailed understanding, please refer to the original transcript.

New Section

This section discusses the ligaments and synovial membrane of the knee joint.

Ligaments of the Knee Joint

• The anterior cruciate ligament (ACL) originates from the external condyle, while the posterior cruciate ligament (PCL) originates from the internal condyle. This is represented by the mnemonic AEPI.

• The synovial membrane lines all articular surfaces of the knee joint, including the tibia, femur, and patella. It is protected externally by the joint capsule.

• The adipose ligament is a fibrous band that extends from the intercondylar area of the femur to the inferior and posterior part of the patella.

• The synovial membrane excludes the cruciate ligaments but includes the menisci within its synovial cavity.

Movements of the Knee Joint

• The primary movements of the knee joint are flexion and extension, with a range of motion between 130 to 160 degrees.

• There is also a movement of medial and lateral rotation when flexing or extending the knee joint. This can be observed by rotating inward or outward with abduction and adduction movements of the foot while seated.

• Inversion and eversion movements primarily occur at the hip joint rather than at the knee joint when standing with extended knees.

• Additionally, there is a slight lateral and medial tilting movement that occurs when bringing knees together or separating them while standing.

The transcript provided does not include any conclusion or closing remarks.