11. Osteology of the distal femur, patella, tibia and fibula Flashcards
(41 cards)
Why does the shaft of the femur descend with a slight medial angulation?
This brings the knees closer to the body’s centre of gravity, hence increasing the stability of the body.
What is located on the posterior surface of the femoral shaft?
Linea aspera - roughened ridge of bone
What does the linea aspera become proximally?
The medial border of the linea aspera becomes the pectineal line proximally
The lateral border becomes the gluteal tuberosity for insertion of the gluteus maximus
What does the linea aspera become distally?
- Distally, the linea aspera widens and forms the floor of the popliteal fossa
- the medial and lateral borders form the medial and lateral supracondylar lines.
- The medial supracondylarline ends at the adductor tubercle, where the adductor magnus muscle inserts. • • • The lateral supracondylar line ends at the lateral femoral condyle.
What is the distal femur characterised by?
The medial and lateral condyles
What forms the knee joint?
The medial and lateral condyles articulate with the tibia and patella to form the knee joint
Why is the medial femoral condyle larger than the lateral femoral condyle?
It bears more weight in the standing position because the centre of mass of the body passes medial to the knee joint
Where is the trochlear (patellofemoral) groove located?
Lies on the anterior surface of the distal femur articulates with the patella
What does the lateral femoral condyle help to prevent?
- The more prominent lateral femoral condyle helps prevent lateral displacement of the patella during patellar tracking.
- People with a flatter lateral femoral condyle (a natural anatomical variant) are more likely to experience patellar instability
What do the inferior and posterior surfaces of the femoral condyles articulate with?
The meniscus of the knee and the tibia
What are the epicondyles?
The medial and lateral epicondyles are bony elevations above the non-articular areas of the condyles
Which epicondyle is larger?
medial epicondyle is larger
Where do The medial and lateral collateral ligaments of the knee originate from?
The medial and lateral collateral ligaments of the knee originate from their respective epicondyles
Where do the ligaments of the knee attach?
- The anterior cruciate ligament (ACL) attaches to the medial aspect of the lateral femoral condyle
- the posterior cruciate ligament (PCL) to the lateral aspect of the medial femoral condyle
What is the intercondylar fossa?
A depression found on the posterior surface of the femur between the two condyles
Where is the patella located?
- at the anterior aspect of the knee joint
- within the trochlear (patellofemoral) groove
- its superior aspect is attached to the quadriceps tendon
- its inferior aspect is attached to the patellar ligament
Describe the shape of the patella bone
- triangular shaped
- has anterior and posterior surfaces
- the apex is inferior and connected to the tibial tuberosity by the patella ligament
- the base forms the superior aspect of the bone and provides the insertion area for the quadriceps tendon
How is the posterior surface of the patella marked?
• articulates with the femur
• marked by two facets:
> medial which articulates with the medial femoral condyle
> lateral that articulates with the lateral femoral condyle
What are the functions of the patella?
- By enabling 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.
- It reduces the frictional forces between the quadriceps and the femoral condyles during extension of the leg.
What is the proximal tibia aided by?
It is widened by the tibial medial and lateral condyles which aid in weight bearing
Where does the proximal and distal ends of the tibia articulate?
It has expansions at its proximal and distal ends where it articulates at the knee and ankle joints respectively
What is the tibial plateau?
A flat surface formed by the tibial condyles that articulates with the femoral condyles to form the major articulation of the knee joint
Where does the head of the fibula articulate with the proximal tibia?
at the proximal tibiofibular joint. It does not form part of the knee joint.
Where is the intercondylar area located?
The intercondylar area is located between the tibial condyles
