The popliteal artery is one of the major arteries of the leg. It is a continuation of the femoral artery, travels across the popliteal fossa, and finally bifurcates into the anterior and posterior tibial ends. Across it journey it gives off numerous branches that supply several structures such as the knee joint and its components, together with major muscles of the leg.
The popliteal artery is the continuation of the femoral artery that begins at the level of the adductor hiatus in the adductor magnus muscle of the thigh. As it continues down, it runs across the popliteal fossa, posterior to the knee joint. The popliteal artery passes obliquely through the popliteal fossa and then travels between the gastrocnemius and popliteal muscles of the posterior compartment of the leg.
It then continues into the deep part of the posterior compartment of the leg, passing under the tendinous arch between the two heads of the gastrocnemius and immediately bifurcates into the anterior and posterior tibial arteries. The popliteal artery is the deepest vascular structure of the popliteal fosa, running closely to the knee’s capsule.
The popliteal artery is the major contributor to the blood supply of the knee joint. Despite its short course, the popliteal artery has several branches:
The popliteal artery gives off five genicular branches that contribute to the periarticular genicular anastamosis that supply the knee joint capsule and ligaments. The five branches are:
- Superior lateral genicular artery
- Superior medial genicular artery
- Middle genicular artery
- Inferior lateral genicular artery
- Inferior medial genicular artery
The superior lateral and medial genicular arteries arise from the popliteal artery and curve around their respective femoral condyles, supplying the bone of the femoral condyles, the adjacent synovium of the knee joint and the superior part of the patella.
The single and smaller middle genicular artery branches off the popliteal artery behind the distal femoral intercondylar region where it runs anteriorly and penetrates the posterior part of the knee joint capsule. It supplies the posterior cruciate ligament, the posterior part of the anterior cruciate ligament and the posterior aspects of the menisci.
The inferior lateral and medial genicular arteries branch off the popliteal artery and run around the tibial condyles, deep to the collateral ligaments of the knee. These arteries supply the adjacent areas including the joint capsule of the knee, the collateral ligaments and tendons, the anterior part of the anterior cruciate ligament and the inferior part of the patella.
The popliteal artery has various muscular branches that provide vascular supply to the hamstring, gastrocnemius, soleus and plantaris muscles. The superior muscular branches of the popliteal artery anastamose with the deep femoral and gluteal arteries of the thigh.
The sural arteries are large vessels that arise on each side of the popliteal artery to provide a vascular supply to the gastrocnemius, soleus and plantaris muscle.
When the popliteal artery ends at the inferior border of the popliteus muscle it bifurcates into the anterior and posterior tibial arteries.
Although the popliteal artery is difficult to palpate (as it runs deep within the popliteal fossa) a popliteal pulse can be felt. This can be achieved with the patient in a lying position with their knee up and flexed so that the popliteal fascia and hamstrings are relaxed. The pulsing of the popliteal artery can then be felt at the inferior aspect of the popliteal fossa. This is important since a weak or absent popliteal pulse may indicate obstruction of the femoral artery and vascular compromise.
Popliteal Artery Haemorrhage
Although dislocation of the knee is uncommon, this can occur in severe, high energy trauma or due to a powerful force applied to the joint. Following knee dislocation, there is a high chance that the popliteal artery may become damaged due to its close proximity to the joint. When the knee is dislocated, it can stretch the popliteal artery causing it to contuse, tear, rupture or break completely. This can then lead to damage of the popliteal vein and, furthermore, damage to the calf muscles. Without intervention, this can lead to limb loss.
Popliteal Artery Entrapment Syndrome (PAES)
The popliteal artery runs between the two heads of the gastrocnemius muscle of the leg. Any variations that occur here can lead to intermittent claudication (pain due to insufficient blood supply) during muscle contraction. This leads to repetitive trauma to the popliteal artery which in turn may result in arterial thrombosis and thromboembolism or formation of aneurysms.
The popliteal artery entrapment syndrome can be classified based on what caused the popliteal artery to become compressed. Types 1 and 4 are due to abnormalities in the course of the popliteal artery, while types 2 and 3 are due to an abnormal insertion of the medial head of the gastrocnemius muscle. Type 5 is entrapment of both the popliteal artery and popliteal vein whereas type 6 is compression of the popliteal artery during leg movements but in the absence of any anatomic abnormality. Treatment involves surgically releasing the popliteal artery by myotomy (removal of muscle) of either the medial or lateral head of the gastrocnemius.