11/30 Knee + Leg Flashcards
What is the superior border of the popliteal fossa?
Hamstrings
Laterally biceps femoris muscle
Medially semimembranosus muscle
What is the inferior border of the popliteal fossa?
Gastrocnemius muscle (lateral & medial heads)
What is the posterior (roof) border of the popliteal fossa?
Skin, popliteal fascia
What is the anterior (floor) border of the popliteal fossa?
Femur, investing popliteus fascia/muscle
What are the nerves of the popliteal fossa?
Sciatic nerve (L4-S3)
Branches into: Tibial nerve (L4-S3), common fibular nerve (L4-S2)
Where does the tibial nerve go? What is the cutaneous branching?
Continues within the posterior leg
Medial sural cutaneous nerve (contributes to sural nerve)
Where does the common fibular nerve go? What is the cutaneous branching?
Divides into superficial and deep fibular nerve
Continues within the lateral and anterior leg
Lateral sural cutaneous nerve (contributes to sural nerve)
What is the largest and most superficial joint?
The knee
What kind of joint is the knee?
Primarily a hinge type of synovial joint (flexion/extension), also does gliding and rotation about a vertical axis
What are the articulations of the knee?
2 femorotibial articulations, lateral and medial
1 femoropatellar articulation
What bone is not involved in the knee joint?
The fibula
The strength of the knee joint is dependent on?
Strength of the associated muscles and ligaments
What provides the most muscular stabilization of the knee? What is the most stable position of the knee?
Quadriceps femoris
Extended knee (taut ligaments)
What is the Q-Angle?
A line representing the resultant line of force of the quadriceps, made by connecting a point near the ASIS to the mid-point of the patella
A line of gravity, “weight-bearing line”.
What mechanism locks the knee in full extension?
“Screw Home” mechanism
Where does the “screw home” mechanism occur? What allows this to happen?
Occurs between 20 degrees of knee flexion and full extension
A combination of lateral rotation of the tibia and passive medial rotation of the femur
What is the result of the “screw home” mechanism
tightening of both cruciate ligaments, which locks the knee in extension
How does the “screw home” mechanism unlock?
Popliteus muscle initiates “unlocking” followed by lateral rotation of femur to enable knee flexion
What is the knee joint capsule made of?
External fibrous layer, internal synovial membrane
What is the external fibrous layer of the knee joint capsule?
Incomplete external portion of the capsule
What is the internal synovial membrane of the knee joint capsule?
Completely lines the articular cavity
Lines the internal surface of the fibrous layer laterally and medially but separates centrally
Posteriorly reflects into the intercondylar area almost separating the R&L femorotibial articular cavities
How is the joint capsule of the knee strengthened?
By 5 extracapsular ligaments
What are the 5 extracapsular ligaments which strengthen the knee joint (anterior/posterior)?
Anterior: Patellar tendon, fibular/lateral collateral ligament (F/LCL), tibial/medial collateral ligament (T/MCL)
Posterior: oblique popliteal ligament, arcuate popliteal ligament
What is the patellar tendon and where does it attach?
Distal extension of the quadriceps tendon
Attaches to tibial tuberosity
What is the Fibular/Lateral Collateral Ligament (F/LCL) and where does it attach?
Strong “cord-like” band of dense C.T.
Lateral epicondyle of femur to head of fibula
Where does the popliteus tendon pass?
Between Fibular/lateral collateral ligament and lateral meniscus