Session 4: Osteology of the Distal Femur, Patella, Tibia and Fibula Flashcards
Where can you find the linea aspera?
On the posterior surface of the femoral shaft.
Explain the lines of the femur.
Proximally the pectineal line from the medial side and the gluteal tuberosity from the lateral side merges in to form the linea aspera. The linea aspera descends the femur and splits into the medial supracondylar line and the lateral supracondylar line. Here it also forms the floor of the popliteal fossa.
Where does the medial supracondylar line end?
At the adductor tubercle.
What muscle inserts at the adductor tubercle?
Adductor Magnus.
Label the diagram.
Label the diagram
What articulates with the patella?
The trochlear (patellofemoral) groove.
Why is the medial femoral condyle larger than the lateral femoral condyle?
Because in standing position the centre of mass of the body passes medial to the knee joint.
Which one is larger, the medial or lateral epicondyle?
The medial epicondyle.
Outline the features of the medial and lateral epicondyles.
What originates at the lateral epicondyle?
What originates at the medial epicondyle?
Bony elevations superior the non-articular areas of the condyles.
Lateral collateral ligament. (lateral)
Medial collateral ligament. (medial)
Label the diagram.
What does the inferior and posterior surfaces of the femoral condyle articulate with?
The menisci of the knee and the tibia.
The lateral femoral condyle is more prominent than the medial. What happens if there is a flatter lateral femoral condyle?
The prominence helps prevent lateral displacement. If it is more flat you are more likely to experience patellar instability.
What is the intercondylar fossa?
A depression found on the posterior surface of the femur between the two condyles.
Where is the patella located.
What is the patella attached to superiorly and inferiorly?
At the anterior aspect of the knee joint within the trochlear groove of the femur.
The patella is attached to the quadriceps tendon superiorly.
The patella is attached to the patellar ligament inferiorly.
Label the diagram.
1 = Posterior meniscofemoral ligament
2 = Posterior cruciate ligament
3 = Anterior cruciate ligament
4 = Lateral meniscus
5 = Medial meniscus
Label the diagram.
Label the diagram
- What does the medial facet articulate with?
- What does the lateral facet articulate with?
- Medial condyle of the femur
- Lateral condyle of the femur
What three main functions does the patella have?
- Extension of the leg by acting as a fulcrum. The quadriceps muscle directly cross the anterior aspect of the knee. Patella therefore enhances the leverage that the quadriceps tendon can exert on the femur.
- Protection - protects the anterior aspect of the knee joint from physical trauma
- Stabilising structure by reduction of the frictional forces on the femoral condyles.
What are the most superior parts of the proximal tibia?
The condyles form a flat surface - what is it called?
Medial and lateral condyle of the tibia.
Tibial plateau.
What does the tibial plateau articulate with?
The femoral condyles to form the major articulation of the knee joint.
How does the head of the tibula articulate with knee joint?
It doesn’t.
It articulates with the proximal tibia at the proximal tibiofibular joint.
Label the diagram.
What attaches at the intercondylar eminence?
What does the intercondylar tubercles of the tibia articulate with?
Anterior cruciate ligament and the menisci of the knee joint.
The intercondylar fossa of the femur.
Where does the posterior cruciate ligament attach?
To the posterior edge of the intercondylar area.
Tibia is prism-shaped. What are the three borders?
Outline their features and attachments.
Anterior: Proximal aspect of the anterior border is marked by the tibial tuberosity. Insertion site for the patellar ligament.
Posterior: Marked by a ridge of bone known as soleal line - site of origin for part of the soleus muscle.
Lateral: Known as the interosseous border. Attachment to the interosseous membrane that binds the tibia and the fibula together.
- What is the medial malleolus?
- What does it articulate with?
- What is lateral to the medial malleolus?
- A bony projection continuing inferiorly on the medial aspect of the tibia.
- Articulate with the tarsal bones to form part of the ankle joint.
- The lateral malleolus but there is also a fibular notch where the fibula is bound to the tibia forming the inferior tibiofibular joint.
Label the diagram.
What is the main function of the fibula?
Act as attachment for muscles - not as weight-bearer.
What are the three main articulations of the fibula? What do they articulate with?
Proximal tibiofibular joint - articulates with the lateral condyle of the tibia
Distal tibiofibular joint - articulates with the fibular notch of the tibia
Ankle joint - articulates with the talus bone of the foot
The knee joints consists of two articulations.
- Which?
- What do they articulate with?
- Tibiofemoral - the medial and lateral condyles of the femur articulate with the medial and lateral tibial condyles.
- Patellofemoral - the patella articulates with the femur at the trochlear groove.
What are the joint surfaces lined with?
Hyaline cartilage.
Which is the weight-bearing joint of the knee?
The tibiofemoral joint
How is the knee joint supplied with blood?
By genicular anastomoses around the knee which are supplied by the genicular branches of the femoral and popliteal arteries.
There are two menisci. Which?
What are the made of?
Medial and lateral menisci.
Fibrocartilage.
Give the two main functions of the menisci.
- To deepen the articular surface of the tibia to increase the stability of the joint.
- To act as shock absorbers by increasing surface area to further dissipate forces.
Explain the structure of the menisci.
C-shaped and they are thicker peripherally than centrally.
What is the medial meniscus attached to?
Medial collateral ligament medially and the intercondylar area of the tibia.
What is the lateral meniscus attached to?
Intercondylar area. Nothing on the periphery.
What is the main difference between the lateral and medial menisci?
Why is this important clinically?
The medial is much more rigid because it is attached to the medial collateral ligament.
The lateral doesn’t attach to the lateral collateral ligament so it is much more mobile, also it is smaller than the medial menisci.
It’s important because it means that the medial is more prone to injury. Damage to the medial collateral ligament can lead to a tear in the medial meniscus.
How are the menisci connected to each other?
Anteriorly by the transverse ligament of the knee.
Where is the posterior meniscofemoral ligament and what is its function?
Located posterior to the posterior cruciate ligament and helps stabilise the posterior horn of the lateral menisucs by attaching it to the medial femoral condyle.
Why is the healing of the menisci impaired?
Because the blood flow to the menisci is poor and gets even worse as you age.
Label the diagram.
The major ligaments in the knee joint can be divided into three categories.
Which? - Examples
Intracapsular ligaments - cruciate ligaments
Ligaments that strengthen the capsule - oblique popliteal ligament
Extracapsular ligaments - collateral ligaments, patellar ligament
What are the two cruciate ligaments?
1 - attachments
2 - attachments
- Anterior cruciate ligament attaching proximally to the posterolateral aspect of the intercondylar fossa - passes distally and anteromedially - attaches to the anterior aspect of the intercondylar eminence of the tibia.
- Posterior cruciate ligament attaching proximally to the medial border and roof of the intercondylar fossa - passes distally and posterolaterally to attach to the posterior intercondylar area of the tibia.
What is the role of the ACL?
Resist anterior translation and medial rotation of the tibia in relation to the femur.
(Limits anterior movement of tibia on femur)
What is the role of the PCL?
Main stabiliser of the weight-bearing flex knee and limits the posterior movement of tibia on femur.
Explain the orientation of the cruciate ligaments.
PAMs APpLes where you consider both cruciate ligaments from distal to proximal.
Posterior passes anterior inserts medially
Anterior passes posterior inserts laterally
What is the joint capsule strengthened by?
Laterally and medially by the inferior fibres of the vastus lateralis and vastus medialis.
Strengthened posteriorly by the oblique popliteal ligament.
What is the oblique popliteal ligament?
A continuation of some of the fibres from semimembranous tendon in a superolateral direction from its main insertion on the medial tibial condyle, posteriorly across the back of the knee, to the lateral femoral condyle.
Briefly outline the patellar ligament.
Where does it insert?
Where does it originate?
A continuation of the quadriceps femoris tendon distal to the patella.
Inserts onto the tibial tuberosity.
What are the roles of the collateral ligaments?
Act to stabilise the hinge motion of the knee, preventing excessive medial or lateral angulation of the tibia on the femur.
Explain the features of the medial collateral ligament + attachments.
A wide flat ligament found on the medial side of the joint.
Proximally attaches to the medial epicondyle of the femur, distally it attaches to the medial condyle of the tibia.
What is the role of the MCL?
Resisting valgus (lateral) forces on the tibia.
What is the role of the lateral collateral ligament?
Resists varus (medial) force on the tibia.
Explain the features and the attachments of the LCL.
Thinner and rounder than the MCL. Attaches proximally to the lateral epicondyle of the femur. Distally it attaches to a depression on the lateral surface of the fibular head.
Lateral collateral ligament is reinforced by the iliotibial tract.