chapter 18 knee Flashcards
define the Patella
Triangular-shaped sesamoid bone
Within quadriceps muscle tendon
Broad superior border
Distally somewhat pointed
explain the weight-bearing activity (closed chain)
Posterior glide of femur results in femur rotating medially on the tibia
Tibia fixed and proximal component moves
Occurs last 20 ◦ of extension
define the function of the patellofemoral
Increases mechanical advantage of quadriceps muscle
Protect knee joint
explain the function of the q angle
from tibial tubercle to the middle of the patella
from the middle of the patella to the ASIS
Normal angle ranges
13-18°
Q angle > in females
what is the q angle define as
angle between the rectus femoris muscle and the patellar tendon
Angle < than 13 degrees associated with
Chondromalacia patellae
Angle > 19 degrees associated with
Chondromalacia patellae
Subluxing patella
Genu valgus
Tibial torsion
what is normal range of tibial - femoral angle
Normal ~ 165 - 180 ◦
define Genu Valgus
less than 165
define genu varum
grater than 180
the origin and insertion of the AC L
Attaches to the anterior surface of the tibia in the intercondylar area just medial to the medial meniscus
Runs superior and posterior
Attaches posteriorly on the lateral condyle of the femur
the origin and insertion of PCL
Attaches to the posterior tibia in the intercondylar area
Runs superior and anterior
Attaches to the anterior femur on the medial condyle
the function of ACL
Prevents anterior tibial displacement on femur and posterior displacement of femur on tibia
Tight during extension
the function of PCL
Prevents posterior tibial displacement on femur / anterior displacement of femur on tibia
Tight during flexion
A patient’s foot is planted on the ground. They were hit by a force to their anterior femur which pushes the femur posterior. Which cruciate ligament is most likely to be torn in this scenario?
the ACL, when the force hits the anterior femur and pushes it posteriorly, it will stretch the ACL as the femur moves posteriorly
define the medial collateral ligament
Flat, broad ligament
Attaches to medial condyles of femur and tibia
Attaches to medial meniscus
May see associated injuries
Protects against lateral stress
define the the lateral collateral ligament
Round, cordlike ligament
Attaches lateral condyle of the femur and runs down to the head of the fibula
No attachment to menisci
Strong, seldom injured
Protects against medial stress
what are the both functions of collateral ligaments
Provide stability in the frontal plane
Tight during extension
Slack during flexion
Both ligaments posterior to knee axis
If a patient was standing or running and they were hit by a force to the lateral aspect of their tibia with their foot planted, which collateral ligament would most likely be torn?
The medial collateral ligament – because it is put on stretch with the above type of force.
what are the functions of the menisci
Purpose:
Shock absorption
Deepen the joint surface
Thicker laterally
Proximal surfaces are concave
what are the menisci
Two half-moon, wedge-shaped fibrocartilage disks – do NOT have a blood supply
knee closed pack what movement is the tibiofemoral
full extension with tibial lateral rotation
knee closed pack what movement is the patellofemoral
full flexion
knee open pack what movement is tibiofemoral
25 degrees flexion
