MSK - The Popliteal Fossa

Question 1

What are the four borders of the popliteal fossa?

Answer 1

• Superiomedial border = Semimembranous
• Superiolateral border = Biceps femoris
• Inferiomedial border = Medial head of the gastrocnemius
• Inferiolateral border = Lateral head of the gastrocnemius and plantaris

Question 2

What is the roof and what is the floor of the popliteal fossa?

Answer 2

• Roof = Popliteal fascia (continuous with fascia lata) and skin
• Floor = Posterior surface of the knee joint capsule

Question 3

What are the contents of the popliteal fossa? (Medial to lateral please)

Answer 3

• Popliteal artery
• Popliteal vein
• Tibial nerve
• Common fibular nerve

Question 4

What is the most superficial of the contents of the popliteal fossa?

Answer 4

• Tibieal and common fibular nerves (branches of the sciatic nerve)
• Common fibular follows biceps femoris tendon

Question 5

How does the small saphenous vein enter the popliteal fossa?

Answer 5

• Pierces the popliteal fascia of the popliteal fossa

- Drains into the popliteal vein

Question 6

What is the deepest of the contents in the popliteal fossa?

Answer 6

Popliteal artery (continuation of the femoral artery)

Question 7

What is a baker’s cyst?

Answer 7

• Popliteal cyst

- Inflammation of the semimembranous bursa

Question 8

How do baker’s cysts arise? What can happen to them?

Answer 8

• Usually with arthritis of the knee (rheumatoid or osteo)

- Can rupture and produce symptoms similar to DVTs

Question 9

What is a popliteal aneurysm?

Answer 9

• Dilation of the artery (increases by 50%)

Question 10

What can happen as a result of a popliteal aneurysm?

Answer 10

• Compresses other contents
• Tibial nerve is most susceptible to compression by popliteal artery
• Damage presents as leg anesthesia/loss of function

Question 11

How can a popliteal aneurysm be detected?

Answer 11

• Palpable pulsation in the popliteal fossa

- Abnormal arterial sounds

Question 12

What are the borders of the adductor canal?

Answer 12

• Anterior = Sartorius
• Lateral = Vastus medialis
• Posterior = Adductor longus and adductor magnus

Question 13

What marks the apex of the adductor canal?

Answer 13

Adductor hiatus (gap between the adductor and hamstring attachments of the adductor magnus)

Question 14

What is the function of the adductor canal?

Answer 14

Acts as a passageway for structures passing between the anterior thigh and posterior leg

Question 15

What are the contents of the adductor canal?

Answer 15

• Femoral artery
• Femoral vein
• Nerve to vastus medialis
• Saphenous nerve

Question 16

What is an adductor canal block?

Answer 16

• Administration of local anaesthetic to block saphenous vein (and sometimes nerve to vastus medialis)

Question 17

Why are adductor canal blocks used?

Answer 17

• Provide sensory anaesthesia for distal thigh/femur, knee and medial lower leg procedures

Question 18

How is the saphenous nerve located?

Answer 18

Use sartorius and femoral artery as landmarks

Question 19

What is adductor canal compression syndrome? How is it caused?

Answer 19

• Trapping of the nerves in the adductor canal

- Hypertrophy of adjacent muscles e.g. vastus medialis