Knee, popliteal fossa and leg Flashcards
What bones does the knee joint include?
articulation between the distal end of femur (medial and lateral condyles) and proximal tibia (tibial plateau) Also arguably includes the posterior aspect of the patella *note the fibula is NOT included*
find the following landmarks of the knee joint
- lateral/medial epicondyle
- latera/medial condyl of the femur
- patellar surface
- intercondylar fossa
- supracondylar line
Find the following landmarks of the tibia/fibula
- head of fibula
- neck of fibula
- fibullar lateral malleolus
- intercondylar eminence
- tibial tuberosity
- tibial medial malleolus
- soleal line
Why does it hurt so bad to be kicked in the shin?
Because your tibial crest is most anterior and there is no muscular coverage - also why it does not heal well.
What kind of joint is the knee?
modified hinge synovial joint
Describe a synovial joint
- 2 or more bony articulating surfaces
- articular capsule
- synovial membrane
- synovial fluid
- hyaline cartilage
Describe the menisci in the knee
semi- lunar fibrocartilage (medial and lateral)
they deepen the articular surface and act as a cushion
the upper surfaces are in contact with the femoral condyles and the lower surfaces are in contact with the tibial condyles
Name the major ligaments and tendons of the knee joint
- tendon of the quadriceps femoris
- patellar ligament
- tibial (medial) collateral ligament
- fibular (lateral) collateral ligament
- patellar retinacula
- oblique popliteal
What tendon does the patella sit in?
What do you call a bone that grows within a tendon?
The patella is a ‘sesamoid’ bone that sits within the quadriceps tendon in this case.
What are the attachements of the patellar ligament?
lower border of the patella to the tibial tuberosity
What are the attachments of the medial collateral ligament?
attaches from the medial femoral epicondyle to the medial tibia
*it is attached to the medial meniscus - clinically, damage to this ligament could potentially tear the meniscus- damage to the meniscus is difficult to repair due to lack of blood supply*
What are the attachments of the lateral (fibular) collateral ligament?
this ligament is thin and cord-like extending from the lateral femoral epicondyle to the head of the fibula. it is NOT attached to the lateral meniscus or capsule
the popliteus tendon passes inbetween the ligament and the lateral meniscus
Describe the intracapsular ligaments of the knee
Anterior cruciate ligament (ACL) - the ACL stops the tibia from moving forward or femur from sliding posteriorly - attachments from lateral femoral condyle to the anterior tibia
Posterior cruciate ligament (PCL) - stops the tibia from moving backwards or the femur from sliding anteriorly- originates in the medial femoral condyle and inserts at the back of the tibia - the PCL lies medially to the ACL
*called cruciate ligaments because they ‘cross’*
What are the movments at the knee?
flexion (hamstrings- tibial/sciatic nerve)
Extension (quads- femoral nerve)
Medial and Lateral rotation - occurs when knee is in flexion by contraction of alternate hamstring muscles
How and why does the knee ‘lock’ and ‘unlock’?
Why? increased stability while standing - less energy use
Locking: happens in full extension- femur rotates medially on tibia
unlocking: ligaments become untwisted and relaxed
*popliteus muscle LATERALLY rotates the femur on the tibia*
Name the synovial bursae
- Suprapatellar bursa - behind quads tendon
- prepatellar bursa- responsible for ‘housemaids knee’ anteior to patella
- infrapatellar bursa- deep to patellar ligament responsible for cleryman’s knee
- semimembranosus bursa- between membrane and joint
- popliteal bursa- communicates with joint cavity
What is the blood supply/nerve supply to the knee?
blood = genicular arteries and popliteal artery
nerve= (remember hilton’s law - the nerve supplying the muscle that crosses the joint also innervates it) - femoral nerve, tibial nerve, and common peroneal nerve
How to test for ACL rupture?
‘Anterior Drawer Test’ = ask to lay down with knees up and feet on table - pull leg towards the foot of the bed and if the tibia moves more than 5 mm anteriorly (not stopped by the ACL) then the acl is damaged
What are the attachments of the popliteus?
from the popliteal surface of the tibia to the lateral condyle of femur and lateral meniscus
Is the popliteus muscle intra capsular?
Yes, it is intracapsular but extrasynovial
What is the action of the popliteus muscle?
laterally rotates the femur on the tibia to ‘unlock’ knee
What is the innervation of the popliteus muscle?
tibial nerve