Part 5: Popliteal Fossa and Knee Joint Flashcards
What forms the upper borders of the politeal fossa?
Diamond shaped. Semi-M and semi-T form medial border and Biceps Femoris forms lateral.
Roof if fascia lata.
What forms the floor of the popliteal fossa?
Popliteal surface of femur, capsule of knee joint and popliteus muscle
Describe the path of common peroneal nerve in relation to the popliteal fossa
Slopes downward medial to BF tendon, then slopes away around lateral side, disappears in substance of peroneus longus. Lies on plantaris, lateral head of gastroc and knee joint capsule then fibula joint of soleus before going into substance of peroneus longus
What are the branches of common peroneal nerve?
Peroneal communicating nerve Lateral cut nerve of calf Superior and Inferior genicular nerves Recurrent genicular nerve Deep and Superficial peroneal nerves
Describe the tibial nerve’s path in relation to popliteal fossa
Runs vertically down middle of fossa and passes deep between heads of gastroc. Gives a motor branch to all muscles that arise from popliteal fossa. Has one cutaneous branch (sural) which arises in fossa.
Describe the path of the popliteal artery in relation to the popliteal fossa
Initially medial to nerve, then tends lateral through the fossa but returns to being medial of nerve as exits fossa. At all levels popliteal vein lies between artery and nerve. Under the fibrous arch of soleus divides into anterior and posteroir tibial arteries.
What are the arterial branches of popliteal artery?
2 branches (often common trunk) to gastroc heads (sural arteries - end arteries). Genicular arteries - UL, UM (encircle femur), LL and LM (encircle tibia) and middle pierces posterior ligament to suuply cruciate ligaments
What is the origin, insertion, action and innervation of popliteus muscle?
O: Post shaft tibia above soleal line below tibia condyles
I: 1/2 - Lateral surface lateral condyle femur
1/2 - tendon passes into capsule and attaches to lateral meniscus
A: Unlocks extended knee by lateral rotation of femur. Pulls meniscus out of way to prevent damaging crush between tibia and femur
Describe the capsule attachments to the tibia
Capsule is attached around margins of plateau except:
- posteriorly - attached to ridge at low end of groove for PCL
- laterally - prolonged over popliteus tendon down to styloid process of fibula
Describe the capsule attachments to the femur
Adheres to below epiphyseal line down to articular margin except:
posteriorly - attached to intercondylar ridge
laterally - encloses the pit and groove for popliteus tendon
Why is the suprapatella bursa continuous with capsule?
Original capsule perforates and communicates with large suprapatella bursa
What are the extracapsular liagements of the knee joint?
Patella retinaculum - patella to lower tibial condyles as fibrous expansions
Tibial collateral - (in another question)
Fibular collateral - lat femur epicondyle to fibula head - free from capsule
Oblique popliteal ligament - lateral expansion of semi-M
Describe the two parts to tibial collateral ligament
Superficial - medial femoral epicondyle to surface of tibia 12cm distal (seperated from bone by semi-M expansion and inferior genicular vessels higher up)
Deep part - attached to femur and tibia just out of articular margins - continuous with capsule and attached to mensicus
What are the intra-articular ligaments of the knee?
Cruciate ligaments
Transverse ligament - unites anterior horns of meniscus
Describe the cruciate ligaments
ACL: anterior tibia to posterior femur lateral condyle. Prevents backwards displacement of femur on tibia
PCL: Posterior part of tibia forward to medial part medial condyle. Prevents forward displacement of femur on tibia
