Hip/Knee/Popliteal Fossa Flashcards
Illiofemoral ligament
AIIS –> intertrochanteric line
body’s strongest ligament
prevents hyperextension and anterior displacement
spiral fibers unwind during flexion (and extension limited by wet towel)
pubofemoral ligament
pubic bone –> iliofemoral ligament
prevents overabduction
ischiofemoral ligament
ischium –> greater trochanter
WEAKEST of 3 ligaments
prevents posterior displacement
zona orbicularis (orbicular zone)
surrounds neck of femur
CIRCULAR fibers deep to other ligaments
holds femoral had in place
most common dislocation of hip
posterior hip dislocation
(femur is flexed and adducted)
sciatic nerve affected
(pain, paresthesia, weakness of muscles)
Major blood supplier of hip joint
medial circumflex femoral a
acetabular branch of obturator a –> imp during devel, occluded in adults
Nerve supply to hip joint
anterior –> femoral n
posterior/superior –> superior gluteal n
posterior/inferior –> nerve to quadrates femoris and observator internus, obturator nerve
(follow’s Hilton’s law…nerve supply is same as nerves supplying muscle located across and acting on the joint)
hip joint fractures
at femoral neck or intertrochanteric line *not hip itself
individuals 60+ yrs, and in females
if vasculature affected –> need hip replacement to prevent avascular necrosis. Indicated w/ presence of degenerative disease
Knee joint typical movements
flexion/extension with some gliding and rotation
Most rotation occurs with knee joint flexed
Popliteus muscle action on knee joint
o: femur (lateral condyle), lateral meniscus
I: tibia (medial)
fixed tibia –> laterally rotates femur to UNLOCK knee
unfixed –> medially rotates tibia
Joints of the knee
1 tibiofemoral joints (between med and lat femoral condyles and tibial condyles
patellofemoral joint (between patella and femoral condyle, “trochlea”)
Genu varum
“bowlegs”
inc lateral tibiofemoral joint space –> smaller Q angle
Genu valgum
“knock-knees”
inc medial tibiofemoral joint space –> larger Q angle
Patellofemoral syndrome
“runner’s knee”
presents as pain deep to patella, many causes, results from repetetive trauma between patella and trochlea
poor patellar tracking (normally Q angle makes patella want to track laterally, but vastas medalis helps pull patella medially –> if VM weak, then lateral patellar tracking occurs)
Knee joint capsule
2 parts fibrous capsule (external layer) synovial membrane (internal layer)
articular bursa
suprapatellar bursa
prepatellar bursa
subcutaneous and deep infrapatellar bursae
suprapatellar bursa
extension of joint cavity, lined w/ synovial membrane
baker’s cyst
fluid within synovial membrane of joint capsule itself
pouches out posteriorly to popliteal fossa
5 ligaments supporting the knee joint capsule
patellar ligament
tibial (medial) collateral ligament
fibular (lateral) collateral ligament (continuous w/ joint capsule
oblique popliteal ligament
arcuate popliteal ligament
the “new” ligament
anterolateral ligament (ALL)
related to second fracture (lateral to Gerdy’s tubercle)
Medial and lateral meniscus
fibrocartilage discs on the tibial plateau
medial–> C shaped
*attached to medial collateral ligament
lateral –> almost circular
*look for fibula to det lateral side
Meniscus tears MOI
sudden extension or rotation of femur while tibia is fixed
bucket handle or radial tear
Cruciate ligaments
Within fibrous joint capsule, but outside synovial membrane
Keep articular surfaces of tibia and femur opposed while stabilizing knee joint
Anterior cruciate ligament (ACL)
runs from interarticular area of tibia to medial surface of lateral femoral condyle
in extension (weight-bearing) ACL prevents posterior movement of femoral condyles on tibial plateau
in flexion (non-weight bearing) ACL prevents anterior movement of tibia
ACL rupture 10x more likely than PCL
Females 2-8x more likely
Unhappy triad
Lateral blow to knee…
Tear of medial collateral ligament –> bucket handle tear of medial meniscus –> too much pressure on ACL –> ACL tear
Anterior drawer test
Knee flexed 90 degrees
Lax hamstring tendons
Pull tibia anterior from neutral position (ACL should resist)
Posterior cruciate ligament
runs from posterior intercondylar area to lateral surface of medial femoral condyle
prevents. ..
- anterior displacement of femur on tibia
- posterior displacement of tibia on femur
- prevents hyperflexion of knee
in weight bearing flexion…
- stabilizes femur over the tibia
Dashboard injury
Knee in flexion
Body motion forward
Anterior force on tibia drives tibia posteriorally
PCL tear
Knee in flexion
Anterior force on tibia
Which injury?
PCL tear
fall on flexed knee
Posterior sag sign
Tibia is posteriorly displaced
If quadriceps compensating, can perform posterior drawer test
Boundaries of popliteal fossa
semimembranosus
biceps femoris
medial and lateral heads of gastrocnemius
Contents of popliteal fossa
- popliteal a. and v.
- tibial div. of sciatic n.
- common fibular (peroneal) div. of sciatic n.
- popliteal lymph nodes
Popliteal vein –>
Popliteal vein –> small saphenous vein
are more SUPERFICIAL than popliteal a.
Origin and function of middle genicular artery
middle genicular artery branches off anterior side of popliteal a. shoots into knee joint itself
supplies cruciate ligaments, synovium, peripheral menisci
has branches coming off laterally and medially
Nerve supply to anterior knee
proximal –> femoral n.
distal –> common (deep) fibular n.
Nerve supply to posterior knee
tibial n.
Nerve supply to lateral knee
common (superficial) fibular n.
Nerve supply to medial knee
obturator n. and saphenous n.
Motions at the hip
flexion/extension
abduction/adduction
medial rotation/lateral rotation
circumduction=flexion, abduction, extension, and adduction
