S3_L2: Kinesiology of the Knee Complex Flashcards
A non-synovial, false joint, that is the articulation between the posterior patella and femur
Patellofemoral joint
The largest sesamoid bone in the body
patella
It acts as an anatomical pulley for quadriceps tendon thereby increasing the moment arm, thus increasing the torque generating capacity of the muscle. It also lengthens the lever arm of the knee joint, thus increasing the ROM of knee joint.
Patella
divides patella into Medial and Lateral Facets
Vertical ridge
Medial and Odd Facets are divided by this ridge
2nd vertical ridge (More medial)
The normal ratio of the length of patellar tendon to the length of patella
1:1
Used to determine patellar height
Insall-Salvati Index
Characterized by Insall-Salvati Index is >1:1 (>1.2), patella is placed upwards, thus increases length of patellar tendon
Patella alta
Characterized by Insall-Salvati Index is <1:1 (<0.8), patella is placed downwards, thus decreases length of patellar tendon
Patella baja
TRUE OR FALSE: Both patella alta and patella baja affect the effectiveness of anatomic pulley mechanism
True
In Patellofemoral Pain Syndrome/Stress (PFPS), there is pain during weight-bearing (1)___ and during non-weight-bearing (2)___.
- deep flexion
- terminal knee extension
When the knee is extended, only the ____ of patella is in contact with femur.
Inferior pole
TRUE OR FALSE: If the patella is fixed, knee extension and flexion ROM will be increased
False. It will be decreased
Enumerate the patellar motions for the x, y, and z axes
X-axis: flexion and extension
Y-axis: medial and lateral tilting
Z-axis: medial and lateral rotation
What is the knee flexion ROM for normal gait?
Normal gait = 60-70 degrees of knee flexion
Screw-home mechanism is also known as?
Terminal Knee Rotation / Locking Mechanism of the Knee
TRUE OR FALSE: To externally rotate the tibia to lock the knee, there is no muscle acting
True
What muscle medially rotates the tibia to unlock the knee?
Popliteus
Close-packed position of knee
Full knee extension (with tibial ER)
For bony congruence and ligamental tautness
Open-packed position of knee
25°-30° of knee flexion
Arthrokinematics during OKC knee extension
tibia will roll and glide anteriorly
Arthrokinematics during OKC knee flexion
tibia will roll and glide posteriorly
Arthrokinematics during CKC knee extension
femur will roll anteriorly and glide posteriorly
Arthrokinematics during CKC knee flexion
femur will roll posteriorly and glide anteriorly
Enumerate the names of the anterior and posterior fibers of the meniscofemoral ligament
Anterior fibers: ligament of Humphry
Posterior fibers: ligament of Wrisberg
The oblique popliteal ligament is an expansion of what muscle?
Semimembranosus muscle
Acts to control valgus forces and secondary restraint to excessive anterior tibial translation
Medial Collateral Ligament / Tibial Collateral Ligament
Acts to control varus forces and secondary restraint to tibial external rotation
Lateral Collateral Ligament / Fibular Collateral Ligament
Which knee ligament merges with the tendon of biceps femoris to form a conjoint tendon collectively?
Lateral Collateral Ligament / Fibular Collateral Ligament
Condition where the infrapatellar bursae are inflamed
Clergyman’s knee
Condition where the prepatellar bursa is inflamed
Popeye’s Knee / Housemaid’s Knee
Fatty soft tissues found in knee joint that serve as shock absorbers when too much pressure is present (e.g. when kneeling). They also reduce frictional forces between structures.
Fat pads
Represents the vector of the combined pull of quadriceps femoris muscle and the patellar tendon
Quadriceps angle / Q-angle
Normal value range of Q-angle
10-15°
Additional: On average, males present with 14°, while females present with 17°
Enumerate the intersection lines of the Q-angle
- A line from ASIS to the midpoint of patella
- A line from tibial tubercle / tuberosity to the midpoint of patella
TRUE OR FALSE: The superior tibiofibular joint is not considered part of the knee complex. It is not contained within the knee joint capsule and functionally related to the ankle joint.
True