PHTY100 Lecture Notes - Lecture 6: Biceps Femoris Muscle, Semimembranosus Muscle, Gracilis Muscle
ANAT week 6 Functional Anatomy of the Knee
- The knee must be conceptualised into 2 joints:
oThe tibiofemoral joint
oThe patellofemoral joint
Tibiofemoral Kinematics
Tibiofemoral Joint Function
- Allows transmission of body weight from femur to tibia
- Functionally described as condyloid joint (modified hinge joint)
oProvides sagittal plane joint rotation (flexion/extension)
oAdditionally, provides small amount of tibial axial rotation (internal
rotation/external rotation)
- Must distinguish mobility vs stability
Convex-Concave Rule
- In order to understand tibiofemoral joint movement, we must learn terms used to
describe how articular surfaces move on one another
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find more resources at oneclass.com
- Spin all the points of the spinning object contact a spinning point on a stationary
surface
- Roll each point on the object contacts a unique point on the surface
- Glide/slide translation of an object without rolling
- Glide and slide can be used interchangeably
- Male surface behaves differently in spin, roll and glide to the female surface
- Rule where the male joint surface is moving then roll and slide occur in opposite
directions
- Rule: where the female joint surface is moving then roll and slide occur in the same
directions
Mobility of Tibiofemoral Joint Flexion
- Knee flexion when femur is fixed and tibia is moving, the tibia rolls posteriorly and
slides posteriorly eg: pulling heel to bottom in standing female surface is moving
- Knee flexion when tibia is fixed and femur is moving, the femur will roll posteriorly
and slides anteriorly eg: going down into squat male surface is moving
Mobility of Tibiofemoral Joint Extension
find more resources at oneclass.com
find more resources at oneclass.com
- Knee extension when tibia is fixed and femur is moving, the femur will roll
anteriorly and slide posteriorly eg: standing from deep squat male surface is
moving
- Knee extension when femur is fixed and tibia is moving, the tibia rolls anteriorly
and slides anteriorly eg: straightening knee to kick a ball female surface is moving
Screw Home Mechanism
- Close-packed position – therefore gives most stability
- Medial femoral condyle is larger, therefore lateral side will finish roll and glide
before the medial side, causing it to rotate (spin)
- The rotation between the tibia and the femur that occurs during terminal knee
extension
- Occurs due to the medial femoral condyle being larger than the lateral femoral
condyle
- During extension, this results in lateral side of joint completing motion first, resulting
in the tibia laterally rotating in the last 20 degrees of knee extension
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Anat week 6 functional anatomy of the knee. The knee must be conceptualised into 2 joints: the tibiofemoral joint, the patellofemoral joint. Allows transmission of body weight from femur to tibia. Functionally described as condyloid joint (modified hinge joint: provides sagittal plane joint rotation (flexion/extension, additionally, provides small amount of tibial axial rotation (internal rotation/external rotation) In order to understand tibiofemoral joint movement, we must learn terms used to describe how articular surfaces move on one another. Spin all the points of the spinning object contact a spinning point on a stationary surface. Roll each point on the object contacts a unique point on the surface. Glide/slide translation of an object without rolling. Glide and slide can be used interchangeably. Male surface behaves differently in spin, roll and glide to the female surface. Rule where the male joint surface is moving then roll and slide occur in opposite directions.
