Lecture 12: Posterior Thigh and Posterior Leg; Popliteal fossa and knee

Question 1

biceps femoris attachments

Answer 1

proximal: ischial tuberosity (long head) and lateral lip of linea aspera of femur (short head)
distal: head of fibula

Question 2

biceps femoris innervation

Answer 2

tibial division of sciatic n. (long head); common fibular division of sciatic n. (short head)

Question 3

biceps femoris action

Answer 3

hip extension; knee flexion; lateral rotation of leg

Question 4

semimembranosus attachments

Answer 4

proximal: ischial tuberosity
distal: posterior medial condyle of tibia

Question 5

semimembranosus innervations

Answer 5

tibial division of sciatic n.

Question 6

semimembranosus actions

Answer 6

hip extension; knee flexion; medial rotation of leg

Question 7

semitendinosus attachments

Answer 7

proximal: ischial tuberosity
distal: medial superior surface of tibia just inferior to sartorius (contributes to pes aserine)

Question 8

semintendinosus innervations

Answer 8

tibial division of sciatic n.

Question 9

semitendinosus actions

Answer 9

hip extension; knee flexion; medial rotation of leg

Question 10

plantaris attachments

Answer 10

proximal: supracondylar line of femur
distal: calcaneal tuberosity medial to calcaneal tendon (via long narrow tendon referred to as “freshman’s nerve”

Question 11

plantaris innervation

Answer 11

tibial n.

Question 12

plantaris actions

Answer 12

knee flexion and plantar flexion (minor)

Question 13

popliteus attachments

Answer 13

proximal: lateral condyle of femur inferior to attachment of fibular collateral ligament
distal: tibia superior to soleal line

Question 14

popliteus innervation

Answer 14

tibial n.

Question 15

popliteus actions

Answer 15

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

Question 16

gastrocnemius attachments

Answer 16

proximal: 2 heads of origin; lateral condyle (lateral head) and popliteal surface of femur (medial head)
distal: calcaneal tuberosity via calcaneal tendon (achilles’ tendon)

Question 17

gastrocnemius innervation

Answer 17

tibial n.

Question 18

gastrocnemius actions

Answer 18

knee flexion; plantar flexion; raises heel during walking

Question 19

soleus attachments

Answer 19

proximal: soleal line of tibia and posterior surface of fibula
distal: calcaneal tuberosity via calcaneal tendon (achilles’ tendon)

Question 20

soleus innervation

Answer 20

tibial n.

Question 21

soleus action

Answer 21

plantar flexion

Question 22

popliteal fossa borders

Answer 22

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

Question 23

3 main components of popliteal fossa

Answer 23

popliteal artery
popliteal vein
tibial nerve

Question 24

popliteal artery branches

Answer 24

1. anterior tibial a.
2. posterior tibial a.
3. genicular branches

Question 25

popliteal artery

Answer 25

continuation from anterior thigh through adductor hiatus; transverses popliteal foss

Question 26

genicular aa.

Answer 26

branches of popliteal a., contributes to a network of vessels surrounding the knee that provides collateral circulation

Question 27

anterior tibial a.

Answer 27

runs anterior to interosseous membrane of leg to supply anterior compartment and eventually dorsum of foot

Question 28

posterior tibial a.

Answer 28

supplies posterior and lateral components of leg and plantar surface of foot

Question 29

small saphenous v.

Answer 29

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

Question 30

popliteal v.

Answer 30

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

Question 31

tibial n. branches

Answer 31

medial sural n.

Question 32

common fibular n. branches

Answer 32

1. lateral sural n. 2. communicating sural n.

Question 33

tibial n.

Answer 33

most superficial of the three main central components of the fossa; innervated mm. of posterior leg

Question 34

common fibular n.

Answer 34

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

Question 35

lateral sural n.

Answer 35

provides cutaneous innervation to lateral leg

Question 36

medial sural n.

Answer 36

joins at a variable location with communicating sural n. to sural n. Along with sural n. provides cutaneous innervation to posterior leg

Question 37

sural n.

Answer 37

formed from the union of medial sural and communicating sural n. provides cutaneous innervation to posterior leg and lateral margin of foot

Question 38

anterior cruciate ligament (ACL)

Answer 38

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)

Question 39

posterior cruciate ligament

Answer 39

from posterior intercondylar eminence of tibia, anterior and internal to medial condyle of femur restricts hyperflexion of knee and posterior displacement of tibia

Question 40

medial menisci

Answer 40

c-shaped; attached to joint capsule and medial collateral ligament

Question 41

lateral menisci

Answer 41

o-shaped

Question 42

patellar ligament

Answer 42

continuation of quadriceps tendon from patella to tibial tuberosity

Question 43

patellar retinacula

Answer 43

bilateral reinforcements of joint capsule; aponeurotic expansions of the vastus medialis and lateralis

Question 44

fibular collateral ligament (lateral collateral)

Answer 44

tough, cord-like, from lateral epicondyle of femur to head of femur; popliteus tendon intervenes between it and lateral meniscus, restricts adduction at knee

Question 45

tibial collateral ligament (medial collateral)

Answer 45

flat band from medial epicondyle of femur to superior medial surface of tibia firmly attached to medial meniscus

Question 46

oblique popliteal ligament

Answer 46

a recurrent expansion of the tendon of semimembranosus, reinforces joint capsule posteriorly

Question 47

arcuate popliteal ligaments

Answer 47

originates from posterior aspect of head of fibula, extends in a superiomedially direction over the tendon of popliteus. reinforces joint capsule posteriorly

Question 48

screw-home mechanism

Answer 48

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

Question 49

hamstring injury

Answer 49

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

Question 50

knee joint injuries

Answer 50

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

Question 51

unhappy triad

Answer 51

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

Question 52

The short head of biceps femoris muscle is innervated by which nerve?

Answer 52

common fibular n.

Question 53

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?

Answer 53

popliteal a.

Question 54

The femoral artery enters the popliteal fossa (becoming the popliteal artery) by passing through the:

Answer 54

adductor hiatus