Week 12: Knee, ankle, and foot Flashcards
What is the tibial tuberosity an insertion point for?
Quadriceps tendons
3 joints within the knee?
tibiofemoral (2; 1 medial and 1 lateral)
patellofemoral
tibiofibular
4 connective tissues within the knee
joint capsule
menisci
retinaculum
ligaments
What type of joint is the knee?
modified hinge joint
What are the sesmoid attachments of the patella?
quad and patellar tendons to the tibial tuberosity
2 functions of the patella?
extend the lever arm of the quad
distribute compression of the femur
Where does the patella move with flexion? extension?
flex- inferior
ext- superior
What is the function of the MCL?
- Prevents excess valgus force
- Taunt with extension
What is the function of the LCL?
- Prevents excess varus force & external rotation
- Taunt with extension
- Assisted by ITB
What is another name for bow legged?
varus
What is another name for knock knees?
valgus
What is the function of the ACL?
- Prevents excess anterior displacement of tibia on femur
- Also prevents IR & ER
- Taunt: Extension
- Assisted by the hamstrings
What is the function of the PCL?
- Prevents excess posterior displacement of tibia on femur
- Taunt:
- Anterior portion w/ mid-flexion
- Posterior portion w/ full flexion
Why is the PCL less likely to be damaged?
stronger
more useful for open chain activities
What are the passive and active components of the anterior knee joint?
P: ACL, patella
A: quad
What are the passive and active components of the posterior knee joint?
P: PCL, extensor retinaculum, posterior capsule
A: gastroc, popliteus, hamstrings
Normal knee flexion measurements? Extension/
flex- 120-145*
Exten- 0-10*
With an open chain knee motion, what happens arthro-kinematically?
Condyles slide in same direction as bone
Roll in opposite direction
With an closed chain knee motion, what happens arthro-kinematically?
Condyles slide in opposite direction as bone
Roll in same direction
Why is the screw home mechanism important?
- It provides extra stability and mechanism for IR and ER
- it is responsible for locking the knee
when does the screw home mechanism occur
at about 20* of knee flexion and full extension
What muscle unlocks the knee?
popliteus
With the open chain movement, what occurs in the screw home mechanism?
tibia ER/lateral rotates
With the closed chain movement, what occurs in the screw home mechanism?
femur IR/medial rotates
Attachments of the popliteus?
Lateral epicondyle femur (lateral meniscus)
Proximal posteromedial tibia
Actions (2) of the popliteus?
- Knee flexion
- IR tibia w/ knee flexion
Innervation of popliteus?
Tibial N.
If you have a genu valgum position, where do you think the traction and compression occurs?
traction on LCL
compression on MCL
If you have a genu varus position, where do you think the traction and compression occurs?
traction on MCL
compression on LCL
What is genu recurvatum?
knee hyper-extension
What is a Q-Angle? What is it associated with?
- alignment for the quadriceps
- genu valgum because it creates a patellar sublux position
