MSK Knee Flashcards
The knee joint is a modified ____ joint.
Is the _____ joint in the body
hinge joint
largest joint in the body
Normal knee range of motion: Knee flexion: Knee extension: Internal rotation of the knee: External rotation of the knee:
F 135
E 0
IR 10
ER 10
Name the knee extensors (4)
join where?
Quadriceps (femoral nerve L2-4)
- Rectus femoris
- Vastus Lateralis
- Vastus Intermedius
- Vastus medialis obliquus
all join with the patellar tendon.
Vastus medialis and lateralis draw the patella in their respective directions.
Name the knee flexors (7)
Hamstrings
- semimenbranosus (sciatic nerve, tib div L4-S2)
- Semitendinosus (sciatic nerve, tib division: L4-S2)
- Biceps femoris
- Long head (sciatic nerve, tib div L5-S2)
- Short head (sciatic nerve, common peroneal div: L5-S2)
Sartorius (femoral nerve L2-3)
Gracilis (obturator nerve: L2-4)
Gastrocnemus (Tibial nerve S1,2)
Medial rotators of the knee (5)
Semitendinosus (sciatic, tib portion L4-S2)
Semimembranosus (sciatic, tib portion: L4-S2)
Sartorius (femoral nerve: L2,L3)
Gracilis (obturator nerve: L2-4)
popliteus
Lateral rotators of the knee (2)
Biceps femoris (long and short heads)
The _______ is formed by the long axes of the femur and the tibia and reflects the natural valgus attitude of the knee.
Males:
Females:
Q angle - ASIS to middle of patella. Tibial tubercule.
Males 13 degrees
Females 18 degrees
How is tibial rotation with knee flexion accomplished?
the lateral tibial plateau is convex in shape. This allows the lateral femoral condyle to move farther than the medial condyle.
Efficiency of the knee extensor muscles is increased by ____% due to the mechanical advantage provided by the patella.
150
The ____ originates at the lateral femoral condyle, travels through the intercondylar notch, and attaches to the medial eminence.
ACL
Primary function of the ACL:
Limit anterior tibial translation
also prevents backward sliding of the femur and hyperextension of the knee. Limits internal rotation of the femur when the foot is fixed.
____ loosens the ACL. ____ tightens it.
full knee exteneion/internal rotation
flexion/external rotation
ACL deficient knees create increased pressure on_____
posterior menisci.
the _____ originates from the anterolateral portion of the medial femoral condyle around the intercondylar notch and inserts onto the posterior aspect of the tibial plateau.
PCL
Main function of the PCL is:
TO restrain posterior tibial translation.
PCL is looser in ___- and tighter in _____
extension
flexion
In flexion, the ACL pulls the femoral condyles_____
in Extension, the PCL pulls the femoral condyles ______
anteriorly
posteriorly
PCL deficient knees place more force on ____
patellofemoral joint
the ____ originates from the medial femoral condyle and inserts onto the superior aspect of the medial tibia.
medial collateral ligament
Also has attachment to the medial meniscus.
In full extension, the MCL _____ .
Tension is increased with _____.
tightens to full tension. Tension is increased with abduction stress at increasing positions of flexion.
____ originates from the lateral femoral condyle posteriorly and superiorly and attaches to the superior part the lateral fibula.
Lateral collateral ligament
It does NOT have an attachment to the lateral meniscus
The LCL ____ during varus stresses.
Peak stress is achieved with _____
restrains
Peak stress is achieved with adduction when the knee is at 70 degrees of flexion
The ____ arises from the semimbranosus tendon and strengthens the fibrous posterior capsule of the knee joint. and resists knee extension. Name the attachemnts
OPL - oblique popliteal ligament
attached to capsule and lateral meniscus
The ______ provides attachment for the posterior horn of the lateral meniscus and reinforces the lateral aspect of the knee and gives posterior lateral rotary stability.
APLC arcuate popliteal ligament complex.
also provides restraint to the posterior tibial translation
This ligaments attachment can be mistaken for a tear of the posterior horn of the lateral meniscus on MRI.
APLC arcuate popliteal ligament complex.
The ____ part of the menisci is well vascularized
The ___ part is poorly vascularized and usually cannot be surgically repaired
peripheral outer 1/3
Inner 2/3
The ____ meniscus is C shaped while the _____ is O shaped
Medial; lateral
lateral meniscus covers a larger area than the medial meniscus. It is joined to the medial femoral condyle by the posterior meniscofemoral ligament
Name the anterior (4) bursae of the knee
Anterior
- Prepatellar bursa: housemaids knee”, located between skin and anterior patella. Most commonly damaged bursa. Inflammation is caused by prolonged kneeling.
- Suprapatellar bursa - located between the quadriceps femoris muscle and the femur: usually communicates with the joint capsule
- Deep infrapatellar bursa - between patellar tendon and the tibia
- superficial or subcutaneous infrapatellar bursa - “vicar’s knee) - located between the skin and the tibial tuberosity. Associated iwth kneeling in upright position (eg kneeling on a prayer bench)
How many bursae of the knee are there?
Anterior (4)
Lateral (3)
Medial (3)
Posterior (3)
13
Name the 3 lateral bursae of the knee
- between biceps muscle and fibular collateral ligament
- between popliteus muscle and fibular collateral ligament
- between lateral femur condule and popliteus muscle
Name the 3 medial bursae of the knee
- Pesanserinus bursa - located between the tendons of the sartorius, gracilis, semitendinosus muscles and medial collateral ligament (say grace before tea)
- between MCL and semitendinosus
- Semimembranosus and the tibia
Name the 2 posterior bursae of the knee
- between lateral head of gastrocnemius and the capsule.
- between medial head of gastrocnemius and capsule extending under the semimembranosus.
- communicates with the joint cavity, can be irritated by abnormal strain, when distended is known as a BAKERS CYS.