Exam 2 Learning Objectives

Question 1

Active Insufficiency

Answer 1

Occurs when a multi-joint muscle reaches a length (shortened) where it can no longer apply an effective force

Question 2

Passive Insufficiency

Answer 2

Refers to inability of a multi-joint muscle to lengthen to a degree that allows full range of motion of all the joints it crosses simultaneously

Question 3

Normal ROM for the Knee

Answer 3

Flexion
- Active ROM (Hip Extended) → 120 degrees
- Active ROM (Hip Flexed) → 140 degrees
- Passive ROM → 160
Extension
- Active/Passive ROM → -5 to 10 degrees
Rotation and Add/Abduction
- At 0 degrees flexion (full extension) → no frontal or transverse plane movement
- At 30 degrees flexion → mild frontal plane motion (abd/add)
- At 90 degrees → max transverse plane motion
- ER in 90 degrees flexion → up to 45 degrees
- IR in 90 degrees flexion → up to 40 degrees

Question 4

Describe the anatomical differences between femoral condyles and what they effect regarding knee function

Answer 4

Medial femoral condyle is wider than the anterior condyle (Ant to Post)
- Aids in screw home mechanism
Medial femoral condyle projects further distally
- Generates genu valgus
- 1.7 cm longer than lateral on average
Lateral femoral condyle projects further anterior than the medial condyle
- Creates patellar buttress
Tibial plateau has a 5-10 degree posterior slope

Question 5

Medial Meniscus

Answer 5

• C-shaped
• Attached to the MCL
• Posterior horn is attached to the semimembranosus via the capsule

Question 6

Lateral Meniscus

Answer 6

• O-shaped
• More mobile
• Does not attach to collateral or capsular ligaments
• Attaches to the arcuate ligament and popliteus muscle

Question 7

Function of the Meniscus

Answer 7

• Absorb and distribute compression forces
• Facilitate proper motion (center pathway)
• Aid in nutrition of joint
• Aids joint stability facilitated by menisci by making the tibia more concave

Question 8

Load-Bearing Properties of the Meniscus

Answer 8

• Menisci carry up to 70% of the load on the tibia
• 3x greater stress on tibia w/o the menisci
• Forces centralize on the tibia without the menisci instead of being radially directed

Question 9

Movement of the Meniscus

Answer 9

Menisci move with tibia during flexion/extension (direction of glide)
- Flexion → menisci move posteriorly
- Extension → menisci move anteriorly
Move with the femur during rotation
Lateral meniscus moves ~2x as much as the medial (15-20 mm)

Question 10

Types of Meniscal Tears

Answer 10

• Longitudinal
• Bucket handle
• Flap
• Transverse
• Torn Horn

Question 11

Signs/Symptoms of Meniscal Injury

Answer 11

• Joint line pain
• Loss of flexion (> 10 degrees)
• Loss of extension (> 5 degrees)
• Swelling (synovial)
• Crepitus
• Positive special test (see below)

Question 12

Tests for Meniscal Injury

Answer 12

• Apley’s Compression/Distraction
• McMurray’s Test
• Bounce Home Test

Question 13

ACL

Answer 13

- 2 bundles
~ Anteromedial bundle tighter in flexion
~ Posterolateral tighter in extension
- Handles up to 75% of anterior tibial force when knee is at full extension
- Handles up to 90% of anterior tibial force when knee is flexed
- Checks 
~ Anterior tibial shear
~ IR of the femur
~ ER of the tibia
- Special Tests
~ Lachman’s Test
~ Anterior Drawer Test
~ Pivot Shift Test

Question 14

PCL

Answer 14

• Handles b/t 85 and 100% of posterior tibial force at both 30 and 90 degrees of flexion
• Checks
  ~ Posterior tibial shear
  ~ Special Tests
  ~ Sag Test
  ~ Posterior Drawer Test

Question 15

MCL

Answer 15

• Handles up to 50% of the valgus force on the knee
• Checks
  ~ Tibial abduction (valgus force)
  ~ ER of tibia
• Special Tests
  ~ Valgus Stress Test

Question 16

LCL

Answer 16

• Handles ~55% of varus force at full extension and increases with flexion
• Checks
  ~ Tibial adduction (varus force)
  ~ IR of tibia
• Special Tests
  ~ Varus Stress Test

Question 17

Anterior Bursae of the Knee

Answer 17

• Suprapatellar
• Prepatellar (most problematic)
• Subcutaneous infrapatellar
• Deep infrapatellar

Question 18

Posterior Bursae of the Knee

Answer 18

• Popliteus
• Semimembranosus
• Gastrocnemius

Question 19

Medial Bursa of the Knee

Answer 19

Pes Anserine

Question 20

Transverse Ligament

Answer 20

• AKA anterior meniscofemoral ligament

- Helps prevent anterior horns of menisci from moving forward

Question 21

Coronary Ligament

Answer 21

• AKA meniscotibial ligament

- Blends with joint capsule but hold meniscus down to periphery of tibia

Question 22

Function of the Patella

Answer 22

• Aids in knee extension by anteriorly displacing the quadriceps tendon (lengthens the lever arm)
• Allows wider distribution of compressive forces on femur by increasing area of contact with patellar tendon

Question 23

Influence of the Patella on the Lever Arm

Answer 23

• Full flexion- little anterior displacement (small lever arm) → force is the least
• Lever arm rapidly increases (30% in length) during knee extension up to 45 degrees
• Lever arm actually decreases slightly after 45 degrees, requiring more quad force to finish extension → up to 60% more

Question 24

What would happen if there were no patella?

Answer 24

• No knee cap = small force arm since tendon is closer to the groove
• Without a kneecap, full ROM of knee extension will require at least 30% more quad force

Question 25

Parts of the patella that are in contact with the femur during movement

Answer 25

-

Question 26

Patella Baja

Answer 26

-

Question 27

Patella Alta

Answer 27

-

Question 28

Insall Ratio

Answer 28

-

Question 29

Muscle-Tendon Units and Knee Support

Answer 29

-

Question 30

Lower Extremity Tests

Answer 30

-

Question 31

Periods of the Gait Cycle

Answer 31

``` Stance - 60% of the cycle - Foot is in contact with the floor Swing - 40% of the cycle - Foot is off the ground ```

Question 32

Phases of the Gait Cycle

Answer 32

- Initial contact - Loading Response - Mid stance - Terminal stance - Pre swing - Initial swing - Mid swing - Terminal swing

Question 33

Initial Contact

Answer 33

- Initial contact of right heel | - Period of double limb support

Question 34

Loading Response

Answer 34

- Shock absorption with knee flexion - Foot flat - Continued phase of double limb support

Question 35

Mid stance

Answer 35

- End of mid stance when swing limb tibia is vertical | - Body weight shifts towards forefoot on stance limb

Question 36

Terminal stance

Answer 36

- Still period of single limb support | - When body weight moves ahead of forefoot

Question 37

Pre swing

Answer 37

- Initial contact of left foot | - Period of double limb support during pre-swing

Question 38

Initial swing

Answer 38

-

Question 39

Mid swing

Answer 39

-

Question 40

Terminal swing

Answer 40

-

Question 41

Step length

Answer 41

Initial contact of one lower extremity to initial contact of other lower extremity

Question 42

Stride length

Answer 42

Initial contact of one lower extremity to initial contact of the same lower extremity

Question 43

Double support

Answer 43

- Time in which both feet are in contact with the ground | - Makes up about 22% of the gait cycle

Question 44

Width of base of support

Answer 44

Typically 1-5 inches

Question 45

Toe out

Answer 45

Average of 4-7 degrees

Question 46

Cadence

Answer 46

Number of steps a person will take per unit of time

Question 47

Functional role of lower limb during the stance phase

Answer 47

Support, propulsion, balance, force absorption

Question 48

Functional role of lower limbs during the swing phase

Answer 48

Toe clearance, foot trajectory and placement

Question 49

What’s the normal range for measurement in Craig’s test?

Answer 49

- Can give a generalized measurement of hip anteversion | - 8-15 degrees of medial rotation is normal

Question 50

What’s the natural progression of limb alignment from infancy to 7 years of age?

Answer 50

- Infant = varus - 18 months = neutral - 3.5 years = valgus - 7 years = neutral