Nerves, Blood Vessels, and Lymphatics of the Knee and Leg
The knee and leg require nerve supply and circulation, which are provided by a number of nerves blood vessels (arteries and vein) and lymphatics. Most of them can be found in an area called the popliteal fossa.
The following nerves of the popliteal fossa and leg:
Tibial nerve: This nerve branches off the sciatic nerve and runs down the midline of the popliteal fossa. It has branches that serve the muscles of the posterior compartment before moving down toward the ankle and foot.
Common fibular (peroneal) nerve: This nerve branches off the sciatic nerve in the popliteal fossa and runs along the biceps femoris and leaves the fossa to run around the head of the fibula and down the leg to the ankle.
Medial sural cutaneous nerve: This nerve branches off the tibial nerve. It joins the sural communicating branch of the common fibular (peroneal) nerve to form the sural nerve, which innervates the skin on the posterior and lateral parts of the leg.
Lateral sural cutaneous nerve: This nerve branches off the common fibular (peroneal) nerve to supply skin over the lateral part of the leg.
The arteries and veins
The arteries that are found in the popliteal fossa provide blood to structures of the knee, and they also take blood down to the ankle and foot. Following are the arteries that run through the popliteal fossa:
Popliteal artery: This artery continues from the femoral artery at the adductor hiatus, which is a gap between the adductor magnus muscle of the thigh and the femur. It runs down into the popliteal fossa and divides into the tibial arteries.
Genicular arteries: These arteries include the superior lateral, superior medial, middle, inferior lateral, and inferior medial genicular arteries. These arteries form the genicular anastomosis, which is a network of arteries surrounding the knee.
Anterior tibial artery: This artery passes into the anterior compartment of the leg and continues to the ankle. It provides blood flow to the structures of the anterior compartment.
Posterior tibial artery: This artery runs to the posterior compartment of the leg to provide blood to structures in the posterior and lateral compartments.
Fibular artery: This artery branches off the posterior tibial artery and runs down to the posterior compartment of the leg. It also provides blood to the lateral and posterior compartments.
Blood that’s finished delivering oxygen and nutrients to the knee, leg, and foot needs to return to the heart, and it does so via veins with corresponding names that accompany the arteries. The popliteal vein is the main vein located in the popliteal fossa. It starts from the posterior tibial vein and travels upward through the popliteal fossa, up into the thigh, and eventually becomes the femoral vein. Following are other veins that serve the knee and leg:
Lateral superior genicular vein: Located superior to the lateral condyle of the femur; drains into the popliteal vein
Lateral inferior genicular vein: Below the lateral condyle of the tibia; also drains into the popliteal vein
Great saphenous vein: A superficial vein that travels from the foot, along the medial side of the knee, and all the way up to the hip
Small saphenous vein: A superficial vein that travels along the lateral side of the ankle to the posterior leg and empties into the popliteal vein
The lymph nodes
The popliteal fossa also contains a few lymph nodes. Popliteal lymph nodes receive lymph from superficial and deep lymphatic vessels and the joint capsule. Superficial lymphatic vessels from the lateral side of the foot and leg accompany the small saphenous vein to the popliteal nodes. The deep lymphatic vessels follow along sides of the deep veins of the leg to the popliteal nodes. The lymph from these nodes flows in the deep lymphatic vessels of the thigh to the deep inguinal nodes.