Sem 2 - J - Knee joint - Articulations, capsule, synovial membrane & bursae, Ligaments, Menisci, Arterial Supply Flashcards
There a number of tendons from the thigh muscles that insert at the knee joint * Quadriceps tendon * Sartorius * Gracilis * Biceps femoris * Semimembranosus * Semitendanosus
State the distal attachment of each of these muscles
- Quadriceps tendon - to patella which attaches to the tibial tuberosity via the patellar ligament
- Sartorius, gracilis, semitendinosus - to the superior surface of the medial tibia - forming the pes anserinus (goose foot)
- Biceps femoris - to the head of the fibula
- Semimembranosus - to the posterior surface of medial condyle of the femur
What type of joint is the knee joint and what are the articulations at the knee joint?
The knee is a modified synovial hinge joint - therefore allows for extension, flexion and a little medial/lateral rotation Ariculations Femorpatellar Femorotibial x2 The fibula does not articulate at the knee joint
A sesamoid bone is a small bone embedded ina tendon or muscle What is the small sesamoid bone embedded in the tendon of the lateral head of the gastrocnemius? Where is it in relation to the femur
The fabella is a small sesamoid bone found in the tendon of the lateral head of the gastrocnemius behind the lateral condyle of the femur
Describe the articular surfaces of the knee joint
The medial and lateral condyles of the femur come anterior to merge & form the patellar surface
The patella has a medial and lateral facet which ineserts into the patellar surface of the femur
The medial & lateral tibial condules are very flat for the femoral condyles to sit on
Why is the lateral aspect of the patellar surface larger?
What direction does the apex of the patella point in the anatomical position?
Below the patellar surface of the femur there is a fossa, what is this known as and what is it for?
The lateral aspect of the patellar surface is larger to help prevent lateral dislocation of the patella during extension
The apex of the patella points inferiorly when in the anatomical position
Below the patellar surface of the femur is the intercondylar fossa for the intercondylar eminence of the tibia
Describe the attachments of the knee joint capsule?
Anteriorly the knee joint capusle fuses with the patella, quadriceps tendon and patellar ligament Posteirorly the knee joint capsule encloses the femoral condyles and intercondylar fossa of the femur and the tibial condyles except where it opens posterior to the lateral condyle of the tibia for the popliteus muscles
The synovial membrane of the knee joint attaches to the articular surfaces inside the knee joint What separates the synovial membrane from the fibrous capsule of the knee joint?
The synovial membrane is separated from the fibrous capsule of the knee joint y the popliteus muscle at the posterior aspect of the lateral condyle of the tibia
What are the folds of synovial membrane in the knee joint?
Medial and lateral alar folds of synovial membrane cover the inner surface of the infrapatellar fat pads which lie on either side of the patella ligament
The medial and lateral alar folds converge to form a single band known as the infrapatellar synovial fold which inserts into the intercondylar fossa of the femur
Can see the infrapatellar synovial fold very clearly here Name all of the bursae associated with the knee joint?
- * Suprapatellar bursae
- * Subcutaneous pre-patellar bursae
- * Subcutaneous infrapatellar bursae
- * Deep infrapatellar bursae
- * Gastrocnemius bursae
- * Semimembranosus bursae
- * Popliteus bursae
- * Anserine bursae
Knee bursae are sacs surrounding the knee joint that are filled with synovial fluid. The knee bursae can be either communicating or non-communicating with the knee joint itself.
What is the function of the knee bursae?
Which knee bursae are communicating with the knee joint?
The bursae facilitate movement and reduce friction where tendons of muscles pass over bony prominences
Communicating knee bursae - Suprapatellar bursae Gastroncemius bursae Popliteal bursae Semimembranosis bursae
Ligaments of the knee
Extracapsular:
- * Oblique Popliteal
- * Arcuate Popliteal
- * Medial and Lateral Collateral
Intracapsular:
- * Anterior and Posterior Cruciate
What is the oblique popliteal ligament & what is its function?
The oblique popliteal ligament is an expansion of the semimembransos tendon which reinforces the posterior aspect of the knee joint capsule
Ligaments of the knee Extracapsular: * Oblique Popliteal * Arcuate Popliteal * Medial and Lateral Collateral Intracapsular: * Anterior and Posterior Cruciate What is the arcuate popliteal ligament & what is its function?
The arcuate popliteal ligament is a thickening of the knee joint capsule over the popliteal tendon which strengthens the posterolateral aspect of the knee joint
Ligaments of the knee Extracapsular: * Oblique Popliteal * Arcuate Popliteal * Medial and Lateral Collateral Intracapsular: * Anterior and Posterior Cruciate Describe the medial collateral ligament and its attachments? What movement does it limit?
The medial (tibial) collateral ligament is a strong, flat thickening of the knee joint capsule
Attachment - from the medial epicondyle of the femur to the medial condyle and superior medial surface of the tibia Its deep fibres attach to the medial mensicus
The medial collateral ligament limits abduction at the knee joint
Ligaments of the knee Extracapsular: * Oblique Popliteal * Arcuate Popliteal * Medial and Lateral Collateral Intracapsular: * Anterior and Posterior Cruciate Describe the lateral collateral ligament and its attachments? What movement does it limit?
The lateral (fibular) collateral ligament is strong and cord like
Attachment - from the lateral epicondyle of the femur to the lateral head of the fibular
It limits adduction at the knee joint
Which tendon splits on either side of the lateral collateral ligament? Which tendon runs deep to the lateral collateral ligament of the knee?
The tendon of the biceps femoris is spit on either side of the lateral collateral ligament of the knee at its insertion into the head of the fibula The tendon of the popliteus runs deep to the lateral collateral ligament of the knee to attach to the lateral condyle of the femur
What is the attachment of the anterior cruicate ligament?
The ACL attaches from the anterior intercondylar area of the tibia and runs posteriorly and laterally to the medial side of the lateral condyle of the femur
During its passage from tibia to femur the ACL undergoes a medial spiral What is the degrees of this medial spiral of the ACL? restate the attachments
During its attachment from the anterior intercondylar area of the tibia to the medial side of the lateral condyle of the femur, the ACL undergoes a medial spiral of approximately 110 degrees
What is the attachment of the posterior cruicate ligament?
The posterior cruciate ligament attaches from the posterior intercondylar area of the tibia to the lateral side of the medial condyle of the femur
What is the function of the PCL?
- * What does it prevent between tibia and femur?
- * What movement does its bands prevent?
The PCL prevents posterior translation of the tibia on the femur (prevents the femur sliding anteriorly on the tibia) particularly when the knee is flexed
- The anterolateral band limits flexion
- The posteromedial band limits extension
State again the attachments of the ACL and PCL
ACL attaches from the anterior interocndylar area of the tibia to the medial side of the lateral condyle of the tibia
PCL attaches from the posterior itnercondylar area of the tibia to the lateral side of the medial condyle of the femur
Describe the movements limited by ACL and PCL
- ACL
- * Prevents the femur sliding posteriorly on the tibia preventing hyperextension of the knee and limits medial notation of the knee when the foot is planted
- * Anteromedial band limits flexion
- * Posterolateral band limits extension
- PCL
- * Prevents the femur sliding anteriorly on the tibia particularly when the knee is flexed
- * Anterolateral band limits flexion
- * Posteromedial band limits extension
Why is the ACL more prone to damage than the PCL? What is the unhappy triad?
The ACL is more prone to damage because impact to the lateral aspect of the knee is more common Impact on a flexed knee as well as from the side can cause a twisting injury leading to ACL rupture ACL, medial collateral ligament and medial meniscus is the unhappy triad
How are the medial and lateral menisci different?
The medial meniscus is C-shaped, broad posteriorly and firmly attached to the medial collateral ligament
The lateral mensicus is circular, freely movable and is an attachment for the tendon of the popliteus
What artery pierces the joint capsule posteriorly to supply the cruciate ligaments?
The middle genicular artery pierces the oblique popliteal ligament and posterior joint capsule to supply the cruciate ligaments
Why is the periarticular genicular anastamosis important?
The periarticular genicular anastamosis is impotant because as the popliteal artery is posterior to the knee joint, when the knee is flexed, this anastamosis will allow for continued adequate perfusion of the knee joint and leg
Which artery runs with the saphenous nerve over the knee?
The saphenous branch of the descending genicular artery from the femoral artery runs with the saphenous nerve over the knee
