S4L1 - Osteology Of The Distal Femur, Patella, Tibia And Fibula Flashcards
What is the linea aspera?
A roughened ridge on the posterior surface of the femoral shaft.
At what angle does the femoral shaft descend from the trochanters and why?
The femoral shaft descends at a slight medial angulation from the trochanters in order to bring the knees closer to the body’s centre of gravity, increasing the stability of the body.
What proximal lines form the linea aspera?
The medial proximal border of the linea aspera becomes the pectineal lone with the lateral proximal border becoming the gluteal tuberosity (where the gluteus maximus muscle inserts)
Distally, what lines are formed from the linea aspera?
Distally the linea aspera widens to form the floor of the popliteal fossa and the medial and lateral borders form the medial and lateral supracondylar lines.
Where do the supracondylar lines end?
Medial supracondylar line ends at the adductor tubercle, where the adductor Magnus muscle inserts.
Lateral supracondylar line ends at the lateral femoral condyle
What forms the knee joint?
The medial and lateral condyles of the femur articulate with the tibia and patella to form the knee joint.
The inferior and posterior surfaces of the femoral condyles articulate with the meniscus of the knee and the tibia.
Why is the medial femoral condyle larger than the lateral femoral condyle?
The medial femoral condyle is larger as it bears more weight in the standing position as the centre of mass of the body passes media to the knee joint.
What is the trochlear (patellofemoral) groove?
The trochlear groove lies on the anterior distal surface of the femur. The trochlear groove articulate with the patella.
Why is it important that the lateral femoral condyle is prominent?
To prevent lateral displacement of the patella during patellar tracking. People with a flatter lateral femoral condyle are more likely to experience patellar instability.
What are the medial and lateral epicondyles?
The medial and lateral epicondyles are bony elevations above the non-Articular areas of the condyles (on the side of the knee). The medial epicondyle is largest. The medial and lateral collateral ligaments of the knee originate from their respective epicondyles.
What is the interchondylar fossa?
A depression on the posterior surface of the femur between the two condyles.
Where does the anterior cruciate ligament and the posterior cruciate ligament attach?
The anterior cruciate ligament (ACL) attaches at the medial surface of the lateral femoral condyle.
The posterior cruciate ligament (PCL) attaches to the lateral aspect of the medial femoral condyle.
Where in the patella located?
The patella is located on the anterior aspect of the knee joint within the trochlear (patellofemoral) groove of the femur.
What attaches to the patella?
Superior aspect: Quadriceps tendon
Inferior aspect: Patellar ligament.
Describe the structure of the patella
The largest sesamoid bone in the body. Positioned within the quadriceps tendon. Triangular shaped ( like guitar pick) . The apex of the patella is situated inferiorly and is connected to the tibial tuberosity by the patellar ligament. The base of the patella lies superior and provides an insertion area for the quadriceps tendon.
What facets mark the posterior surface of the patella?
2 facets on the posterior surface mark where the patella articulates with the femur.
Medial facet = articulates with the medial condyle of the femur
Lateral facet = articulates with the lateral condyle of the femur.
What are the main functions of the patella?
- Enables the quadriceps muscle to directly cross the anterior aspect of the knee and by acting as a fulcrum, the patella enhances the leverage that the quadriceps tendon can exert on the femur, increasing the mechanical efficiency of the muscle by 33-50%
- Protection. It protects the anterior aspect of the knee joint from physical trauma
- Reduces the frictional forces between the quadriceps and the femoral condyles during extension of the leg.
What is the tibia?
The main bone of the leg. Shinbone. Has expansions at the proximal and distal ends where it articulates at the knee and ankle joints respectively. 2nd largest bone in the body.
Describe the structure of the proximal tibia.
The proximal tibia widens to form the medial and lateral condyles, aiding in weight-bearing.
The condyles form a flat surface known as the tibial plateau. The tibial plateau articulates with the femoral condyles to form the major articulation of the knee joint.
What is the proximal tibiofibular joint?
The area where the head of the fibula articulates with the proximal tibia. This is of the lateral side of the tibia. The proximal tibiofibular joint is not part of the knee joint.
What is the intercondylar area?
Located between the tibial condyles, the intercondylar area consists of the intercondylar eminence in the centre and on either side of the intercondylar eminence the medial and lateral intercondylar tubercles.
