patellofemoral joint

Question 1

articulation

Answer 1

retro patellar surface of the patella and the anterior aspect of the trochlear groove of the femur

Question 2

the patella is

Answer 2

biconvex

Question 3

trochlea is

Answer 3

concave

Question 4

what is the patella shaped like

Answer 4

inverted triangle

proximal base

distal apex

Question 5

how is the articular surface divided

Answer 5

medial and lateral facets by a central ridge giving the lateral surface a larger surface area

Question 6

hyaline cartilage

Answer 6

thicket of any in the body

especially over the medial facet

Question 7

which condyle of the femur is higher

Answer 7

lateral condyle is higher

gives some lateral osseous stability

Question 8

what kind of joint is the patellofemoral joint

Answer 8

modified plane joint

w/ poor surface congruency

Question 9

capsule of patellofemoral joint

Answer 9

continuous of the tibiofemoral joint

Question 10

functions of the patella

Answer 10

gives the extensor mechanism a greater mechanical advantage

acts as a level and a pulley

decreases the friction b/w the quads and the femoral condyles

acts as a bony shield to protect the anterior joint from trauma

Question 11

patella as a lever

Answer 11

increases the lever arm of the quads

increases the perpendicular distance of the line of force of the quads from the axis of rotation

quads can extend the knee with a lesser amount of force

Question 12

patella as a pulley

Answer 12

redirects the force exerted by the quads and increases the magnitude of the muscle contraction

Question 13

patella facets

Answer 13

superior

inferior

lateral

medial

odd facets

Question 14

what do the facets help with

Answer 14

distribute forces across the patella

Question 15

which facet is the most medial

Answer 15

odd facet

Question 16

what is special about the medial facet

Answer 16

has the most consistent contact while the odd facet has the least

also has the thickest hyaline cartilage

Question 17

trochlear groove

Answer 17

V shaped groove on the distal femur

will correspond to the vertical ridge on the patella

Question 18

what must be able to happen for the patella to perform its function

Answer 18

must be able to slide on the femoral condyles

Question 19

w/ knee flexion, the patella

Answer 19

slides distally on the femoral condyles

seating itself b/w the femoral condyles

Question 20

in full flexion, the patella

Answer 20

sinks into the intercondylar notch

Question 21

what does the patella do during extension

Answer 21

reverses the sliding

patella returns to its position on the anterior surface of the distal femur

Question 22

what is patella tracking

Answer 22

refers to the medial-lateral and cranial-caudal movements of the patella as the knee flexes and extends

only part of the patella articulates w/ the trochlear at any given time

Question 23

in early degrees of flexion –> patellar tracking

Answer 23

the distal portion of the patella articulates w/ the proximal trochlea

Question 24

as the knee continues to flex

Answer 24

the contact area moves proximally on the patella so that by 90 degrees the superior portion of the patella is in contact with the trochlea

Question 25

as flexion continues past 90 degrees

Answer 25

medial facet enters the intercondylar notch

odd facet makes contact for the first time

Question 26

at 130 degrees of flexion

Answer 26

contact is on the lateral and odd facets