CH 6: The Knee Flashcards
Describe the function and stability of the knee.
The knee joint has limited bony stability and is designed for weight bearing and mobility in locomotion.
What stability it has is contributed by the joint capsule, ligaments and muscles that surround the joint.
What leg bone does the patella mainly articulate with?
The Femur
What are the primary functions of the mensci?
- Improves joint congruity and stability by deepening the articulation
- Increases SA for tibia and femur to contact, which provides better load transmission
- Provides shock absorption for the knee
- Assists in lubrication and nutrition of joint capsule
There are 3 vascular zones of the menisci. What are they called and where are they located?
Red-red zone:
-Most superficial
- Highest vascularity
Red-white (pink) zone:
- Middle
- Medium vascularity
White zone:
- Most deep
- Poor vascularity
How would you tell the ACL and PCL apart on an image of the knee?
The Posterior Cruciate Ligament attaches to the POSTERIOR part of the Tibia.
The Anterior Cruciate Ligament attaches to the ANTERIOR part of the Tibia.
These are not their true origins and insertions, but just a way of remembering which ligament is which.
What is a bursa?
A bursa is a small fluid-filled sac, found everywhere in the body to reduce friction and provide cushioning against compression between structures.
What structures does a Terrible Triad injury involve?
A stretched or torn ACL, MCL and medial meniscus.
What is PTFS?
Patella-Femoral Syndrome. This is a catch-all phrase used to describe many different muscle imbalances, which result in mal-tracking, therefore inequal distribution of force on the patella.
Primary functions of the ACL (4)
1) Restricts Ant. translation of the tibia on he fixed femur
2) Restricts Pos. translation of the femur on the fixed tibia
3) Hyperextension of the tibia
4) Rotation of the tibia on the femur
(Opposite functions of the PCL)
Primary functions of the PCL (2)
1) Restricts Pos. translation of the tibia on the fixed femur
2) Restricts Ant. translation of the femur on the fixed tibia
(Exact opposite functions of the ACL)
Which knee ligaments are intracapsular and which ligaments are extracapsular?
ACL & PCL are intracapsular.
MCL & LCL are extracapsular.
Describe the difference between Varus and Valgus forces.
A valgus force is a force that pushes towards the midline of your body, and a varus force pushes outwards, away from your body.
Would a valgus force applied to the knee result in a potential LCL or MCL injury?
MCL. If the force is applied to the knee from the outside, pushing the knee towards the midline, then the medial collateral ligament would suffer tensile and bending forces, which could result in a strain.
Why do athletes that suffer meniscus tears prefer the removal of damaged tissue, compared to sewing/repairing the damaged tissue?
Removal of damaged meniscal tissue results in a expeditious recovery, but at the cost of compromised joint structure.
Repairing the existing tissue is a much slower recovery and cannot resume play as fast, but will have an overall stronger knee in the long run.
What are the 5 types of meniscal tears?
1) Vertical longitudinal
2) Vertical radial
3) Horizontal
4) Bucket handle
5) Oblique
