posterior thigh, knee, popliteal fossa Flashcards
what are the 4 muscles that form the posterior thigh?
- long head bicep femoris
- short head bicep femoris
- semitendinosus
- semimembranosus
what are the muscles that commonly insert on the ischial tuberosity?
- long head bicep femoris
- semitendinosus
- semimembranosus
where does the short head of biceps femoris originate?
linea aspera found on the mid femoral shaft
what is the common insertion points of the long and short head of biceps femoris?
head of fibula
what function is accomplished by the muscles that insert on the ischial tuberosity?
knee flexion, hip extension
what function is accomplished by the short head of biceps femoris?
knee flexion
what is the insertion point of semimebranosus?
posteromedial tibia
what is the insertion point of semitendinosus?
trick to recall?
anteromedial tibia Pes anserinus (SGT)
where is the short head of biceps femoris found relative to the long head?
deep to it
relative to biceps femoris, where are the other posterior thigh muscles found?
most medially we have semimembranosus and lateral to SM is semitendinosus
what nerve is responsible for innervating the short head of the biceps femoris?
common fibular N.
a branch of the sciatic nerve
what spinal levels are associated with the common fibular N?
L4-S2
what muscles of the posterior thigh get innervated by the tibial N. a branch of the sciatic nerve?
- long head biceps femoris
- semimembranosus
- semitendonosus
- hamstring part of adductor magnus
what spinal levels correspond to the tibial N.?
L5-S3
what supplies blood to the posterior thigh?
from the perforating arteries of the deep femoral A.
how do the perforating A. travel from anterior to posterior?
adductor magus has small openings that allow the arteries to pass trough onto the back side
what is the function of the adductor hiatus?
its an opening for the femoral A. and V.
once pass this, they become popliteal A. and V.
what type of joint is the knee joint
modified hinge joint
synovial
how many articulations is the knee joint comprised of? which are?
3 articulations
- medial and lateral condyles of the fibula and tibia (2)
- patella and femur
what type of movements are permitted by the knee joint?
- knee flexion/extension
- slight medial/lateral rotation “lock/unlocking”
what type of bone is the patella?
sesamoid bone
why are the patellar grooves in the femur important?
they ensure that the patella properly articulates due to the lack of ligaments
what is runner’s knee?
mal alignment of the patella in the patellar (trochlear) groove which causes degeneration of the cartilage
how can runner’s knee be corrected or impact be minimized?
the muscles of the quadriceps need to be strengthed, hence if vastus lateralis executes a stronger pull, then vastus medialis needs to be strengthened, can use braces to correct and support
what are the extracapsular ligaments?
lateral (fibular) collateral; ligament (LCL)
medial (tibial) collateral ligament (MCL)
patellar ligament
where is the LCL located?
ranges from lateral femoral epicondyle to the head of the fibula
does the LCL attach to the joint capsule?
no, it is found completely outside
how could the LCL be described?
as a round, cord-like ligament
where is MCL found?
medial femoral epicondyle, proximal tibia to medial meniscus
what is the most commonly injured extra capsular ligament
MCL
how could MCL be described as?
a flat band
does the MCL share an attachment point with the joint capsule?
yes
what may cause the MCL to tear?
Valgus strain causing Abduction of the knee
when talking about adduction/abduction of the knee what does this refer to?
adduction: femur moves inwards relative to center joint midline
abduction: femur is more lateral relative to midline
what may cause the LCL to tear?
varus strain causing for adduction of the knee
how would a MCL injury be assessed?
pressure would be put on the knee on the lateral side towards the medial side
how would a LCL injury be assessed?
pressure from medial to lateral side
what is the main function of the medial and lateral collateral ligaments?
limits rotation, medial and lateral dislocations of the knee and ab/adduction of the knee
where is the patellar ligament located?
from the distal portion of the quadriceps tendon to the tibial tuberosity
what are the intracapsular ligaments of the knee?
- anterior cruciate ligament
- posterior cruciate ligament
- transverse ligament
- posterior meniscofermoral ligament
if the femur is stationary, what movement is being prevented by the ACL?
it prevents the knee joint from moving forward relative to the femur
if the femur is stationary, what movement is being prevented by the PCL?
it prevents the knee joint from moving posterior relative to the femur
if the tibia is stationary, what movement is being prevented by the ACL?
it prevents the knee joint from moving posterior relative to the tibia
if the tibia is stationary, what movement is being prevented by the PCL?
it prevents the knee joint from moving forward relative to the tibia
what is the function of ACL and PCL?
limits anterior (ACL) and posterior (PCL) translation of tibia relative to femur
what does FUMBUL represent?
FUM is respective to PCL
orientation forward, upward, medial
BUL is respective to ACLs orientation backwards, upwards, lateral
combined together what is the fucntion of ACL and PCL?
assist with rotational stability of the knee
what test can be used to evaluate the state of the cruciate ligaments?
lachman’s test/(anterior/posterior) drawer test
what do lachman’s test/ (anterior/posterior) drawer test consist of?
posterior drawer test: posterior push on tibia to see how far it translates relative to femur= test for PCL damage
anterior drawer test: push forward on tibia , see how it moves relative to femur= tests for ACL damage
what does the transverse ligament of the knee connect?
it connects the menisci anteriorly
how is the menisci of the knee formed?
fibrocartilage
what is the role of the menisci in the knee?
provides cushioning for the knee and enhances the congruity of the femoral and tibial condylar articulations
what is the medial meniscus attached to?
MCL
how is the medial meniscus shaped?
c-shaped
what is the lateral meniscus attached to?
no attachment to the lateral meniscus
is the lateral meniscus mobile or immobile?
relatively mobile
how is the lateral meniscus shaped?
circular, almost a complete O
which menisci is more susceptible to injury?
the medial menisci
when do meniscal tears generally occur?
due to sudden extension or rotation of the flexed knee when the leg is fixed
what happens in the “unhappy triad”
- lateral force on knee= rupture to MCL and medial meniscus
- in addition, rotational and valgus strain (knee abduction)= ACL ruputure
what are the bursae found on the anterior knee?
suprapatellar bursa/pouch
prepatella bursa
superficial/deep infrapatellar bursa
what is the suprapatellar pouch a continuation of?
of the synovival cavity
where is the prepatellar bursa located?
between the patella and the skin
where is the superficial/deep infrapatellar bursa located?
on either side of the patellar ligament
what is a clinical significance of the suprapatellar pouch?
it can be used for steroid injections, it avoids having to inject through the bone directly,
what are the bursaes found on the posterior knee?
- medial (2): anserine and semibranosus
- lateral (3)
what type of cushioning is found below the patella?
infrapatellar fat pad
what muscle is directly involved in the unlocking of the knee?
popliteus
where does popliteus originate and insert?
origin: lateral femoral condyle, deep to LCL
inserts: above soleal line of the posterior tibia
how does the muscle contract in medial rotation?
from insertion to origin
during what movement does the medial rotation [when tibia is fixed] (locking) of the knees occur?
when going from an extension to a flexion
ex: sitting over table edge when feet hang off
during what movement does the lateral rotation [when tibia is fixed] (unlocking) of the knees occur?
knee flexion when standing
how does the muscle contract in lateral rotation?
from origin to insertion
what forms the superior medial border of popliteal fossa?
semimebranosus and semitendonosus
what forms the inferiormedial border of popliteal fossa?
medial head of gastrocnemius
what forms the superior lateral border of popliteal fossa?
biceps femoris
what forms the inferior lateral border of popliteal fossa?
lateral head of gastrocnemius and plantaris
what is contained in the popliteal fossa?
- Popliteal A.
- Popliteal V.
- tibial and common fibular n.
how do the common fibular and tibial nerve branch off as?
lateral and medial sural cutaneous N
