Posterior Thigh

Question 1

What is the innervation of the posterior thigh muscles?

Answer 1

Tibial division of the sciatic nerve. EXCEPT for the short head of the biceps femoris which is innervated by the common fibular portion.

Question 2

What muscle action do ALL of the posterior leg muscles participate in?

Answer 2

Leg flexion

Question 3

What is the action of the semitendinosus muscle?

Answer 3

Extend thigh and flex leg and slightly medially rotate

Question 4

What muscles insert on the pes anserinus?

Answer 4

Sartorius m, gracilis m, semitendinosus m

Question 5

What is the action of the semimembranosus muscle?

Answer 5

Extend thigh and flex leg

Question 6

What are the actions of the biceps femoris muscles?

Answer 6

LH - extend thigh and flex leg

SH- flex leg ONLY

Question 7

What is the action of the adductor magnus (hamstring portion)?

Answer 7

Extends thigh

Question 8

What joints are crossed with the adductor magnus (hamstring portion)?

Answer 8

Crosses hip but doesn’t cross knee

Question 9

What are the borders of the popliteal fossa?

Answer 9

Superomedially- semimembranosus and semitendinosus
Superolaterally- biceps femoris
Inferolaterally and inferomedially - gastroc medial and lateral heads

Question 10

What are the contents of the popliteal fossa?

Answer 10

nerves (in particular the tibial n right in the middle)
popliteal vein and LN
popliteal artery and branches

Question 11

What special positional relationships happen within the popliteal fossa?

Answer 11

Superficial to deep:
nerves
popliteal vein and LN
popliteal artery and branches

Question 12

What is the deepest structure in the popliteal fossa?

Answer 12

Popliteal artery

Question 13

What are the components of the genicular anastomosis?

Answer 13

superior medial/superior lateral

inferior medial/ inferior lateral

Question 14

Why is the descending branch of the lateral femoral circumflex artery important?

Answer 14

it is the connector of the cruciate anastomosis at the hip to the anastomosis at the knee. it travels down through the vastus lateralis and emerges lateral to the knee anastomosis with the superior lateral genicular artery. This way, if the nerve has been cut, will get blood to leg

Question 15

what is the termination of the popliteal artery? Where does this bifurcation occur?

Answer 15

anterior and posterior popliteal artery. anterior goes front at the top of the interosseous membrane

Question 16

when does the sciatic nerve develop into its two own independent nerves?

Answer 16

at the apex (top) of the popliteal fossa

Question 17

How does the common fibular nerve leave the popliteal fossa? why is this important?

Answer 17

passes superficial to the head of the gastrocnemius m–>winds around neck and head of fibula–>becomes VERY superficial.
IT IS VERY PRONE TO INJURY.

Question 18

Where does the common fibular nerve bifurcate?

Answer 18

deep to fibularis longus m where it becomes superficial fibular nerve and deep fibular nerve

Question 19

from where does the sural cutaneous branch arise?

Answer 19

from the lateral sural cutaneous nerve

Question 20

What is trochanteric bursitis?

Answer 20

inflammation of the trochanteric bursa
may result from repetitive actions such as climbing stairs while carrying heavy options or running on a steeply elevated treadmill
causes pain in the lateral thigh region
the pain can radiate down the iliotibial tract

Question 21

Describe the cause of hamstring strain

Answer 21

these injuries are common in those who run and or kick hard. the violent muscular exertion required to excel in these sports may tear part of the proximal tendinous attachments of the hamstrings to the ischial tuberosity.

Question 22

What are unique features of hamstring tear?

Answer 22

pain so bad that a person falls to the ground and writhes in pain. this usually is from inadequate warming up before practice or competition

Question 23

How can avulsion (tearing away) of the ischial tuberosity at the proximal attachment of the biceps femoris and semitendinosus occur?

Answer 23

by forcible flexion of the hip with the knee extended like when kicking a football

Question 24

What is compressed in piriformis syndrome? what population of people suffer from this condition?

Answer 24

the sciatic nerve; those that have excessive use of the gluteal region (ice skaters, cyclists, and rock climbers)

Question 25

what results in complete section of the sciatic nerve?

Answer 25

the leg is useless bc extension of the hip is impaired as well as the flexion of the leg and ankle and foot motion

Question 26

what results from incomplete sections of the sciatic nerve? what is the difference between the side of safety and the side of danger?

Answer 26

slow recovery that is usually incomplete. may involve the inferior gluteal n.
safe side = lateral side
danger side = medial side
injury or surgery on the medial side may injure the sciatic nerve and its branches to the hamstrings.

Question 27

Paralysis of the hamstrings results in what?

Answer 27

IMPAIRMENT IN THIGH EXTENSION AND LEG FLEXION

Question 28

What is the function of the popliteal muscle?

Answer 28

The popliteus muscle in the leg is used for unlocking the knees when walking, by laterally rotating the femur on the tibia during the closed chain portion of the gait cycle (one with the foot in contact with the ground).