Functional Anatomy

Question 1

How are the femoral condyles situated? What does this cause?

Answer 1

Medial condyle extends further distally causing a 10 degree valgus angle

Lateral condyle extends further anteriorly to prevent patella dislocation

Question 2

What provides static stability for the knee?

Answer 2

1) Ligaments
- anterior and posterior cruciate ligaments
- lateral and medial collateral ligaments
- coronary ligament (portions of the joint capsule which connect the inferior edges of the fibrocartilaginous meniscus to the periphery of the tibial tuberosity)
- patellofemoral
- posterior oblique/popliteal (supports the posteriomedial corner with the semimembranosis that restricts anteromedial instability)
- arcuate (“Y” shaped, supports the posterolateral corner, control IR of femor on tibia in ckc)
2) Joint Capsule
3) Retinaculum
4) Menisci

Question 3

Dynamic Stability and Movement

Answer 3

(1) Extensor Mechanism
a) Quadriceps
- quad tendon
- patellar tendon (really a ligament)
(2) Flexors
- hamstrings
- sartorius
- gracilis
- popliteus
- gastrocnemius
(3) Tensor Fascia Lata
(4) IT Band

Question 4

Anterior View tendons and Muscles

Answer 4

Quadriceps Tendon
Patellar Tendon 
Pes Anserine Tendons 
Tensor Fascia Lata 
Quadriceps
Muscles of the Hip

Question 5

Posterior View Tendons and Muscles

Answer 5

Hamstring Group
Gastrocnemius
Popliteus (unlocks the knee and internally rotates) tibia
Pantaris

Question 6

Bursea of the Knee

Answer 6

suprapatellar bursa
prepatellar bursa (“housemaid’s knee”)
infrapatellar bursa
pes anserine bursa

Question 7

What could be causing anterior knee pain?

Answer 7

• patellar subluxation
• osgood-schlatter’s
• Jumper’s Knee (patellar tendonitis)
• PFPS
• Chondromalacia of patella
• pre-patellar bursitis
• patellar arthritis

Question 8

What could be causing medial knee pain?

Answer 8

• MCL sprain/tear
• Medial Meniscus Tear
• Pes Anserine bursitis
• plica syndrome
• saphenous neuritis

Question 9

What could be causing Lateral Knee Pain?

Answer 9

• LCL sprain/tear
• Lateral Meniscus Tear
• ITB Syndrome
• Peroneal Nerve Compression

Question 10

What could be causing posterior knee pain?

Answer 10

• Baker’s Cyst (popliteal/synovial cyst, usually from chronic synovitis that gets thick and inflammed)
• PCL Tear

Question 11

Which side of the meniscus is more mobile?

Answer 11

Lateral meniscus is more mobile (10mm with flexion vs 2mm)

Question 12

What provides anterior capsular support?

Answer 12

patella and quad tendon

Question 13

What provides posterolateral instability?

Answer 13

popliteus

Question 14

What provides anteromedial stability?

Answer 14

retinaculum

Question 15

What provides posteromedial stability?

Answer 15

semi-membranosis
pes anserine
MCL
capsule

Question 16

What provided posterior stability?

Answer 16

gastrocnemius and popliteus

Question 17

What provides posterolateral stability?

Answer 17

biceps femoris and LCL

Question 18

What provides anterolateral stability?

Answer 18

retinaculum

IT Band

Question 19

What are the primary functions of the meniscus?

Answer 19

Load distribution
Shock absorption
Joint Stability

Question 20

What are the secondary functions?

Answer 20

joint lubrication
articular cartilage nutrition
proprioceptive feedback

Question 21

What’s a bigger factor in developing OA? ACL or menisectomy in ACL reconstructions?

Answer 21

meniscus

Question 22

Characteristics of articular cartilage?

Answer 22

• covers end of long bones
• decreases friction
• avascular
• lacks nerve supply
• protects subchondral bone

Question 23

Grades of Articular Cartilage Lesions

Answer 23

I= soft spot in cartilage
II= minor tears in surface of cartilage
III= deep crevices in cartilage
IV= full thickness lesions to sub-condral bone

Question 24

When is the ACL on the greatest strain?

Answer 24

30 degrees flexion

Question 25

What are secondary stabilizers to anterior translation?

Answer 25

ITB
MCL
medial and lateral joint capsule

Question 26

What are secondary restraints to posterior translation?

Answer 26

…

Question 27

When is anteromedial bundle loose? taut?

Answer 27

loose in extension

taut in flexion

Question 28

When is posterolateral bundle loose?taut?

Answer 28

loose in flexion

taut in extension

Question 29

Which bundle of the ACL contributes more to Ant/Post stability?

Answer 29

anteriomedial bundle

Question 30

Which bundle of the ACL contributes more to rotational instability?

Answer 30

posterolateral

Question 31

ACL provides secondary restraint for what? And provides what type of feedback?

Answer 31

restraint to varus/valgus stress

provides proprioceptive feedback

Question 32

Compare the PCL of the ACL.

When are the bundles taut and loose?

Answer 32

PCL is twice as strong and thick

Anterolateral bundle (65% of ligament):
taut in flexion
loose in extension

Posteromedial bundle (35% of ligament):
taught in extension
loose in flexion

Question 33

Which ligament, MCL/LCL attaches to the joint capsule?

Answer 33

MCL

Question 34

When is LCL taught?
What motions does it resist?
How does it compare to the MCL?

Answer 34

extrarticular. 
taught in extension
resists varus stress 
resists ER of tibia
secondary restraint to ant/post translation

Compared to MCL:
thinner
more mobile
less often injured

Question 35

MCL is taut in what position? resists what stresses? compared to LCL?

Answer 35

extraarticular. 
taut in extension
resists valgus sress
resists ER of tibia
secondary ant/post translation

Compared to LCL:
thicker
less mobile
more often injured

Question 36

What are plica? What are 4 plica syndromes?

Answer 36

fetal tissue remnants, synovial folds
Syndromes:
mediopatellar
suprapatellar
lateral synovial patella 
infrapatellar (pinch femoral condyle/patella, inflammation)

Question 37

What’s the most common nerve irritation post surgery and why?

Answer 37

saphenous nerve because surgeons use turniquets to slow blood flow