Lecture 12: Posterior Thigh and Posterior Leg; Popliteal fossa and knee Flashcards
biceps femoris attachments
proximal: ischial tuberosity (long head) and lateral lip of linea aspera of femur (short head)
distal: head of fibula
biceps femoris innervation
tibial division of sciatic n. (long head); common fibular division of sciatic n. (short head)
biceps femoris action
hip extension; knee flexion; lateral rotation of leg
semimembranosus attachments
proximal: ischial tuberosity
distal: posterior medial condyle of tibia
semimembranosus innervations
tibial division of sciatic n.
semimembranosus actions
hip extension; knee flexion; medial rotation of leg
semitendinosus attachments
proximal: ischial tuberosity
distal: medial superior surface of tibia just inferior to sartorius (contributes to pes aserine)
semintendinosus innervations
tibial division of sciatic n.
semitendinosus actions
hip extension; knee flexion; medial rotation of leg
plantaris attachments
proximal: supracondylar line of femur
distal: calcaneal tuberosity medial to calcaneal tendon (via long narrow tendon referred to as “freshman’s nerve”
plantaris innervation
tibial n.
plantaris actions
knee flexion and plantar flexion (minor)
popliteus attachments
proximal: lateral condyle of femur inferior to attachment of fibular collateral ligament
distal: tibia superior to soleal line
popliteus innervation
tibial n.
popliteus actions
knee flexion (minor); lateral rotation of femur on fixed tibia (standing), medially rotates tibia of unplanted limb (not standing). Popliteus unlocks the knee to initiate flexion of the knee
gastrocnemius attachments
proximal: 2 heads of origin; lateral condyle (lateral head) and popliteal surface of femur (medial head)
distal: calcaneal tuberosity via calcaneal tendon (achilles’ tendon)
gastrocnemius innervation
tibial n.
gastrocnemius actions
knee flexion; plantar flexion; raises heel during walking
soleus attachments
proximal: soleal line of tibia and posterior surface of fibula
distal: calcaneal tuberosity via calcaneal tendon (achilles’ tendon)
soleus innervation
tibial n.
soleus action
plantar flexion
popliteal fossa borders
superior lateral border: biceps femoris
superior medial border: semimembranosus and semitendinosus
inferior: heads of gastrocnemius
roof: skin, superficial and deep fascia
floor: popliteal surface of femur, oblique popliteal ligament and fascia of popliteus
3 main components of popliteal fossa
popliteal artery
popliteal vein
tibial nerve
popliteal artery branches
- anterior tibial a.
- posterior tibial a.
- genicular branches
popliteal artery
continuation from anterior thigh through adductor hiatus; transverses popliteal foss
genicular aa.
branches of popliteal a., contributes to a network of vessels surrounding the knee that provides collateral circulation
anterior tibial a.
runs anterior to interosseous membrane of leg to supply anterior compartment and eventually dorsum of foot
posterior tibial a.
supplies posterior and lateral components of leg and plantar surface of foot
small saphenous v.
originates from the lateral aspect of the dorsal venous arch of the foot; can be found travelling in close proximity to the sural n.; empties into popliteal v. in the popliteal fossa
popliteal v.
continuation of the posterior tibial v,; begins at the distal border of popliteus. travels with artery. becomes femoral v. after passing through the adductor hiatus
tibial n. branches
medial sural n.
common fibular n. branches
- lateral sural n.
- communicating sural n.
tibial n.
most superficial of the three main central components of the fossa; innervated mm. of posterior leg
common fibular n.
lateral and smaller terminal branch of sciatic n. travels along the medial border of the biceps femoris and its tendon; innervates mm. of anterior and lateral leg
lateral sural n.
provides cutaneous innervation to lateral leg
medial sural n.
joins at a variable location with communicating sural n. to sural n. Along with sural n. provides cutaneous innervation to posterior leg
sural n.
formed from the union of medial sural and communicating sural n. provides cutaneous innervation to posterior leg and lateral margin of foot
anterior cruciate ligament (ACL)
from anterior intercondylar eminence of tibia, posteriorly and externally to lateral condyle of femur; resists hyperextension of the knee and anterior displacement of the tibia (weaker than PCL)
posterior cruciate ligament
from posterior intercondylar eminence of tibia, anterior and internal to medial condyle of femur restricts hyperflexion of knee and posterior displacement of tibia
medial menisci
c-shaped; attached to joint capsule and medial collateral ligament
lateral menisci
o-shaped
patellar ligament
continuation of quadriceps tendon from patella to tibial tuberosity
patellar retinacula
bilateral reinforcements of joint capsule; aponeurotic expansions of the vastus medialis and lateralis
fibular collateral ligament (lateral collateral)
tough, cord-like, from lateral epicondyle of femur to head of femur; popliteus tendon intervenes between it and lateral meniscus, restricts adduction at knee
tibial collateral ligament (medial collateral)
flat band from medial epicondyle of femur to superior medial surface of tibia firmly attached to medial meniscus
oblique popliteal ligament
a recurrent expansion of the tendon of semimembranosus, reinforces joint capsule posteriorly
arcuate popliteal ligaments
originates from posterior aspect of head of fibula, extends in a superiomedially direction over the tendon of popliteus. reinforces joint capsule posteriorly
screw-home mechanism
when the knee is fully extended with the foot on the ground, the knee passively locks because of the medial rotation of the femoral condyles on the tibial plateau
hamstring injury
pull or torn hamstrings are common in individuals who run/kick hard. result from tearing or evulsions of the proximal tendinous attachments of the hamstrings to the ischial tuberosity
knee joint injuries
most common is ligament sprain, which can occur when the foot is fixed on the ground and cannot move and force is applied to the knee
unhappy triad
tearing of TCL, medial meniscus and ACL; these structures can be torn together when there is excessive lateral twisting of the flexed knee, such as a pivot movement
The short head of biceps femoris muscle is innervated by which nerve?
common fibular n.
When the femur is fractured, the broken distal end often turns posteriorly to enter the popliteal fossa due to muscle traction. Because of its position deepest in the fossa, which structure is most vulnerable to laceration?
popliteal a.
The femoral artery enters the popliteal fossa (becoming the popliteal artery) by passing through the:
adductor hiatus
