Lecture 13: Post. Thigh & Popliteal Fossa

Question 1

What is the common proximal attachment for posterior thigh muscles?

Answer 1

Ischial tuberosity -> except short head of biceps femoris

Question 2

What is the innervation for the posterior thigh muscles?

Answer 2

Tibial division of sciatic nerve -> except short head of biceps femoris

Question 3

What nerve innervates the short head of biceps femoris?

Answer 3

Common fibular portion of the sciatic nerve

Question 4

What is the function of the posterior thigh muscles?

Answer 4

All flex the leg

All except for short head of biceps femoris extend thigh

Question 5

What nerve innervates gracilis?

Answer 5

Obturator n

Question 6

What nerve innervates semitendinosus?

Answer 6

Tibial division of sciatic nerve

Question 7

What nerve innervates sartorius?

Answer 7

Femoral nerve

Question 8

What muscles insert at Pes Anserinus?

Answer 8

Gracilis
Semitendinosus
Sartorius

Question 9

What is the innervation of the adductor magnus muscle?

Answer 9

Hamstring portion = tibial division of sciatic nerve

Adductor portion = posterior division of obturator nerve

Question 10

What is the function of the hamstring portion of adductor magnus?

Answer 10

Extend thigh (doesnt cross knee joint so cant do anything for the leg)

Question 11

What is the deepest structure in the popliteal fossa?

Answer 11

Popliteal artery

Question 12

Where does the popliteal artery come from?

Answer 12

It was the femoral artery -> the femoral artery becomes the popliteal artery once it passes through the adductor hiatus

Question 13

What does the popliteal artery give rise to?

Answer 13

Genicular branches

Question 14

Why do we need the genicular anastomosis?

Answer 14

Because when you bend at the knee you are occluding the popliteal artery, so this provides blood supply to the knee during that

Question 15

What artery can be traced all the way from the thigh to the knee and is able to supply blood to the knee in the event of a femoral artery injury?

Answer 15

Descending branch of the lateral femoral circumflex artery

Question 16

The popliteal artery ends by dividing into what 2 arteries?

Answer 16

Anterior tibial artery

Posterior tibial artery

Question 17

The popliteal artery terminates by branching into the anterior and posterior tibial arteries. The posterior tibial artery branches again quickly giving rise to which structure?

Answer 17

Fibular (peroneal) artery

Question 18

The popliteal vein is formed by union of what 2 veins?

Answer 18

Anterior and posterior tibial veins -> usually near inferior border of popliteus muscle

Question 19

What does the small saphenous vein terminate into?

Answer 19

The popliteal vein

Question 20

The sciatic nerve usually ends at the superior angle of the popliteal fossa where it divides into what 2 nerves?

Answer 20

Tibial nerve

Common fibular nerve

Question 21

Every muscle in the posterior compartment of the leg is innervated by what nerve?

Answer 21

Tibial nerve

Question 22

What nerve winds around the head and neck of the fibula and is susceptible to injury?

Answer 22

Common fibular nerve

Question 23

The tibial nerve gives rise to what sural cutaneous nerves?

Answer 23

Medial sural cutaneous nerve

Question 24

The common fibular nerve gives rise to what sural cutaneous nerves?

Answer 24

Sural communicating branch and the lateral sural cutaneous nerve

Question 25

What nerve supplies the distal posterior aspect of the leg and lateral aspect of ankle and foot?

Answer 25

Sural nerve

Question 26

Why is pain from a popliteal abscess or tumor so severe?

Answer 26

Because the fascia is very tough and this can spread through the popliteal fascia inferiorly and superiorly

Question 27

What is the best way to feel the popliteal pulse?

Answer 27

The popliteal artery is deep, so its hard to palpate the pulse, however if you flex the knee to relax the hamstrings, you can feel for the pulse inferiorly to the popliteal fossa

Question 28

What would a weakening of the popliteal pulse indicate?

Answer 28

An occlusion or problem with the femoral artery

Question 29

Why is injury to the tibial nerve uncommon?

Answer 29

Its deep and protected in the popliteal fossa but can be damaged by deep lacerations or posterior dislocation of the knee joint

Question 30

What would a severed tibial nerve result in?

Answer 30

A loss of plantarflexion and flexion of the toes (posterior compartment = flexors) and also would lead to loss of intrinsic foot muscles

Question 31

The compartments of the leg have very strong fascia and septa and infections in the leg can spread in these compartments. In what direction does infection usually spread in each compartment?

Answer 31

Anterior and posterior compartments = distally

Lateral compartment = proximally (along course of fibular nerve into popliteal fossa)

Question 32

Pronation of the foot evolved due to what muscles?

Answer 32

Fibularis longus distal attachment across the sole of the foot and the development of the fibularis tertius

Question 33

What is the general function of the anterior compartment of the leg?

Answer 33

Dorsiflexion

Question 34

What is the general function of the lateral compartment of the foot?

Answer 34

Eversion of the foot

Question 35

Overuse of the anterior compartment leg muscles can cause edema and swelling, and compress which nerve? What does this lead to?

Answer 35

Deep fibular nerve -> leads to pain and numbness in the space between the 1st and 2nd digits (flip flop region)

• Can be caused by tight fitting ski boots, known as “ski boot syndrome”

Question 36

Which nerve provides cutaneous innervation to the medial surface of the leg and foot?

Answer 36

Saphenous nerve.