TBL8 - Popliteal Fossa and Posterior Leg

Question 1

Where do the tibial nerve, popliteal artery, and popliteal vein travel through? Where does the common fibular (peroneal) nerve course along? What surrounds the popliteal lymph nodes?

Answer 1

1) The tibial nerve, popliteal artery, and popliteal vein course through the center of the popliteal fossa
2) The common fibular (peroneal) nerve courses along the lateral border of the fossa
3) Varying amounts of white fat surround the neurovascular and lymphatic structures of the popliteal lymph nodes

Question 2

Name the muscles that form the superomedial, superolateral, inferomedial and inferolateral borders of the popliteal fossa. What is the popliteal fascia continuous with proximally and distally?

Answer 2

1) Superolaterally by the biceps femoris (superolateral border)
2) Superomedially by the semimembranosus, lateral to which is the semitendinosus (superomedial border)
3) Inferolaterally and inferomedially by the lateral and medial heads of the gastrocnemius, respectively (inferolateral and inferomedial borders)
4) Posteriorly by skin and popliteal fascia (roof)
5) The popliteal fascia is continuous proximally with the fascia lata and distally with the deep fascia of the leg

Question 3

Where does the popliteus muscle attach to proximally? What does the popliteus muscle form in relation to the popliteal fossa? What does the popliteus tendon separate?

Answer 3

1) The popliteus muscle attaches proximally to the lateral condyle of the femur
2) It forms part of the popliteal fossa floor
3) The popliteus tendon separates the LCL and lateral meniscus before attaching distally on the superoposterior tibia

Question 4

What is the function of the popliteus muscle?

Answer 4

When standing, the popliteus rotates the femur laterally 5⁰ on the tibial plateau to release the knee from its locked position and thereby initiates the transition from standing to walking

Question 5

Where is the popliteal artery located in relation to the tibial nerve and popliteal vein? Where does the popliteal artery reside?

Answer 5

1) The popliteal artery is deep to the tibial nerve and popliteal vein
2) The popliteal artery resides on the floor of the popliteal fossa

Question 6

What do branches of the popliteal, femoral, and anterior tibial arteries anastomose to form? What is the function of this?

Answer 6

1) Branches of the popliteal, femoral, and anterior tibial arteries anastomose to provide a collateral circulation around the knee joint
2) The many arteries making up the peri-articular anastomosis around the knee provide an important collateral circulation for bypassing the popliteal artery when the knee joint has been maintained too long in a fully flexed position or when the vessels are narrowed or occluded

Question 7

What is the larger, more direct terminal branch of the popliteal artery? What does it supply?

Answer 7

1) The posterior tibial artery is the larger, more direct terminal branch of the popliteal artery
2) It supplies the posterior leg

Question 8

What is a branch of the posterior tibial artery? What does it supply?

Answer 8

1) The fibular artery is a proximal branch of the posterior tibial artery
2) The fibular artery supplies muscles on the lateral side of the posterior leg and the fibularis longus and brevis muscles of the lateral leg

Question 9

Why can palpation of the popliteal arterial pulse be difficult and what can cause its weakening or absence?

Answer 9

1) Because the popliteal artery is deep, it may be difficult to feel the popliteal pulse
2) Weakening or loss of the popliteal pulse is a sign of a femoral artery obstruction

Question 10

Where is the posterior tibial pulse palpated and why is its absence in people over 60 related to intermittent claudication?

Answer 10

1) The posterior tibial pulse can usually be palpated between the posterior surface of the medial malleolus and the medial border of the calcaneal tendon
2) Although posterior tibial pulses are absent in approximately 15% of normal young people, absence of posterior tibial pulses is a sign of occlusive peripheral arterial disease in people older than 60 years. For example, intermittent claudication, characterized by leg pain and cramps, develops during walking and disappears after rest. These conditions result from ischemia of the leg muscles caused by narrowing or occlusion of the leg arteries

Question 11

Where do the two heads of the gastrocnemius muscle arise from? Where does the single head of the soleus muscle arise from?

Answer 11

1) The two heads of the gastrocnemius muscle arise from the distal end of the femur
2) The single head of the soleus arises from the proximal fibula and tibia

Question 12

What is the common tendon of the gastrocnemius and soleus muscles? Where does it attach distally? What do the two muscles do during walking, running, and jumping?

Answer 12

1) The calcaneal (aka Achilles) tendon is the common tendon of the gastrocnemius and soleus muscles
2) It attaches distally to the calcaneal tuberosity
3) During walking, running, and jumping, the two muscles plantarflex the foot

Question 13

Why does rupture of the calcaneal tendon cause the most severe acute problem of the leg?

Answer 13

1) Calcaneal tendon rupture is probably the most severe acute muscular problem of the leg. Individuals with this injury cannot plantarflex against resistance (cannot raise the heel from the ground or balance on the affected side), and passive dorsiflexion (usually limited to 20° from neutral) is excessive
2) Ambulation (walking) is possible only when the limb is laterally (externally) rotated, rolling over the transversely placed foot during the stance phase without push off

Question 14

What does the long tendon of the small plantaris muscle join? Does using the plantaris tendon for grafting compromise plantarflexion of the foot?

Answer 14

1) The long tendon of the small plantaris muscle joins the calcaneal tendon
2) Using the plantaris tendon for grafting does not compromise plantarflexion of the foot

Question 15

On which sides of the leg are the flexor hallucis longus and flexor digitorum longus located? What are the superficial and deep muscles of the posterior leg innervated by?

Answer 15

1) The flexor hallucis longus and flexor digitorum longus, immediately deep to the soleus, are located on the lateral and medial sides of the posterior leg, respectively
2) The superficial and deep muscles of the posterior leg are innervated by the tibial nerve

Question 16

Where does the tibialis posterior muscle lie? Where do the deep muscle tendons travel? Where does the flexor hallucis longus tendon enter?

Answer 16

1) The tibialis posterior muscle, another deep muscle, lies between the two flexor muscles (the flexor hallucis longus and flexor digitorum longus) in the same plane as the tibia and fibula
2) The deep muscle tendons course posterior to the medial malleolus
3) The flexor hallucis longus tendon enters the groove under the sustentacular tali

Question 17

Where does the flexor hallucis longus tendon travel? What does it attach to distally? What is its function?

Answer 17

1) The flexor hallucis longus tendon crosses the sole of the foot deep to the tendon of the flexor digitorum longus
2) The flexor hallucis longus attaches to the distal phalanx of the big toe
3) After plantarflexion lifts the heel off the ground, the flexor hallucis longus delivers the final trust to propel the foot off the ground during walking, running, and jumping

Question 18

Where does the flexor digitorum longus attach to distally? What is its function?

Answer 18

1) The tendon of the flexor digitorum longus attaches to the distal phalanges of the lateral four toes
2) Thus, the muscle flexes the toes
3) The flexor digitorum longus tendon also provides active support to the medial longitudinal arch during weight bearing

Question 19

Where does the tendon of the tibialis posterior attach to? What is the main function of the tibialis posterior?

Answer 19

1) The tendon of the tibialis posterior attaches mainly to the navicular bone at the high point of the medial longitudinal arch
2) The main function of the tibialis posterior is to:
a) provide active support to the arch during weight bearing
b) when the foot is off the ground, the muscle works synergistically with the tibialis anterior to invert the foot