Musculoskeletal: Anatomy - Knee joint and popliteal fossa Flashcards
What makes up most of the contents of the popliteal fossa?
Fat
Four superficial boundaries of the popliteal fossa
Superolateral: medial border of biceps femoris
Superomedial: semimembranosus and semitendinosus
Inferior: lateral and medial heads of gastrocnemius
Roof: skin, popliteal fascia
Three deep boundaries of the popliteal fossa
Superior: medial and lateral condylar lines of femur
Inferior: soleal line of tibia
Floor: popliteal surface of femur, posterior aspect of knee joint capsule, popliteus and investing fascia
Six contents of the popliteal fossa
- Termination of small saphenous vein (pierces popliteal fascia)
- Popliteal arteries and veins (and their branches)
- Tibial nerve
- Common fibular nerve
- Posterior cutaneous nerve of thigh
- Popliteal lymph nodes and lymphatic vessels
What is the popliteal fascia continuous with superiorly and inferiorly?
Superiorly: fascia lata
Inferiorly: deep fascia of leg
Branches of tibial nerve and their functions
- Motor to:
- Soleus
- Plantaris
- Gastrocnemius
- Popliteus
- Posterior compartment of leg - Medial sural cutaneous
- Joins sural communicating branch of common fibular to form the sural nerve (which then supplies sensation to the lateral leg and ankle) - Medical calcaneal, and medial and lateral plantar nerves:
- Sensory to dorsum of foot and posterior leg
- Medial and lateral plantar nerves supply intrinsic foot muscles
Where does the sciatic nerve divide into the tibial and common fibular nerves?
At the apex of the popliteal fossa
Describe the course of the tibial and common fibular nerves in the popliteal fossa
Tibial: bisects popliteal fossa vertically, exits between heads of gastrocnemius
Common fibular: lateral to tibial nerve, follows medial border of biceps femoris then exits passing superficial to lateral head of gastrocnemius and head of fibula before winding around neck of fibula
Four branches of the common fibular nerve and their functions
- Sural communicating branch:
- Joins medial sural nerve from tibial nerve to form sural nerve (supplies lateral leg and ankle) - Lateral cutaneous nerve of calf:
- Supplies skin over upper peroneal and extensor compartments - Superior and inferior genicular nerves:
- Travels with vessels to supply the knee capsule and lateral collateral ligament - Recurrent genicular nerve:
- Perforates tibialis anterior to supply capsules of superior tibiofibular joint and knee joint
Describe the course of the popliteal artery
Continuation of the femoral artery after it passes through the adductor hiatus
Ends at inferior border of popliteus by dividing into anterior and posterior tibial arteries
List in order of most superficial to deepest in the popliteal fossa: veins, arteries, nerves
- Nerves
- Veins
- Arteries
Five genicular branches and four muscular branches of the popliteal artery
Five genicular:
1. Superior medial
2. Superior lateral
3. Middle
4. Inferior medial
5. Inferior lateral
Four muscular:
1. To hamstrings
2. To soleus
3. To plantaris
4. To gastrocnemius
Which arteries make up the genicular anastamosis?
- Branches of popliteal artery:
- Superior medial
- Superior lateral
- Middle
- Inferior medial
- Inferior lateral - Branch of femoral artery:
- Descending genicular - Descending branch of lateral femoral circumflex
- Branch of anterior tibial artery:
- Anterior tibial recurrent
Describe the course of the popliteal vein
Begins at distal border of popliteus as continuation of posterior tibial vein
Receives small saphenous vein in the popliteal fossa after it pierces the popliteal fascia
Becomes femoral vein as it passes through the adductor hiatus
Describe the relation of the popliteal vein to the popliteal artery and tibial nerve within the popliteal fossa
Inferiorly: lies posteromedial to popliteal artery and lateral to tibial nerve
Superiorly: overlies popliteal artery with tibial nerve on top
Where do the popliteal lymph nodes drain to?
Deep inguinal lymph nodes
Where do the superficial popliteal lymph nodes receive lymph from?
Lymphatics accompanying the small saphenous vein
Where do the deep popliteal lymph nodes receive lymph from?
From joint capsule of knee and from lymphatics accompanying the deep veins of the leg
Proximal and distal attachment, course of tendon, innervation and action of popliteus
Proximal: lateral femoral condyle and lateral meniscus
Distal: posterior tibia, superior to soleal line
Tendon course: lies within capsule of knee joint (enters beneath arcuate popliteal ligament)
Innervation: tibial nerve (L4-5, S1)
Action: weak knee flexor, unlocks knee during flexion (by rotating femur laterally on fixed tibia), acts with PCL to prevent anterior displacement of femur on tibia
What are the three articular surfaces of the knee?
- Medial tibiofibular
- Lateral tibiofibular
- Femoropatellar
Describe the posterior surface of the patella
Larger lateral and smaller medial surface