The Posterior Tibial Artery is a Continuation of the

The posterior tibial artery (PTA) is a major artery that delivers blood to certain areas of the lower leg. It can be affected by conditions such as atherosclerosis and chronic compartment syndrome, in which swelling and inflammation of muscles in the calf press on the artery and block blood flow.

This article describes the anatomy of the PTA, explains how it functions in the body, and discusses the health conditions that can affect it.

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Anatomy

The posterior tibial artery is one of the largest arteries in the lower leg. It branches off from the popliteal artery, a blood vessel behind the knee that is a continuation of the femoral artery. This is important because the femoral artery, along with the femoral vein, is vital for circulating blood between the lower body and the heart.

From where it starts on the popliteal artery, the PTA progresses downward behind the popliteal muscle (a small muscle at the knee joint) and through the soleus muscle. It then passes between a central calf muscle called the tibialis posterior and the flexor digitorum longus, the calf muscle that helps the foot to flex.

The PTA ends at the talus, the bone that makes up the lower half of the ankle joint just above the calcaneus (heel bone).

Several arteries branch off from the PTA at various points. The most important is the peroneal artery, which splits off a couple of centimeters below the popliteus muscle.

Anatomical Variations

As with many parts of the body, the posterior tibial artery sometimes does not look the same in everyone. Variations in the PTA include:

• Hypoplastic or aplastic PTA, in which the artery does not develop fully. This occurs in only around 5% of people. Even less often, in 0.8% of people, both the PTA and the anterior tibial artery (ATA) are hypoplastic.
• Trifurcation, in which a third artery branches off from the popliteal artery in addition to the PTA and ATA
• High origin, which simply means the PTA starts higher up on popliteal artery than normal

Around 13% of the time, when there are variations of the PTA on one leg, the other leg will have the same variations.

Function

The PTA provides blood to the posterior compartment of the leg, which is more commonly known as the calf. There are seven muscles in the calf which, like all muscles, require blood and oxygen to function properly.

The calf muscles that receive oxygenated blood from the PTA are divided into two groups. The flexor hallucis longus, flexor digitorum longus, tibialis posterior, and popliteus muscles are located deep within the calf. The muscles closest to the skin are the ones that give the calf its curved shape. They are the gastrocnemius, soleus, and plantaris muscles.

The PTA also plays a role in providing blood to the bones of the lower leg—the tibia and fibula.

Recap

The posterior tibial artery (PTA) provides blood and oxygen to the seven muscles that make up the calf. It arises from the popliteal artery, which is a continuation of the femoral artery. Along with the femoral vein, the femoral artery is vital for the continual flow of blood between the heart and the lower body.

Clinical Significance

Like most major arteries, a number of health issues can affect the PTA. The are two conditions in particular that may involve the posterior tibial artery.

Peripheral Artery Disease

Peripheral artery disease typically is caused by atherosclerosis. It occurs when plaque—a mixture of cholesterol, other fats, calcium, and inflammatory cells called macrophages—builds up inside an artery.

Plaque can block the flow of blood, which in the case of the PTA means the legs may not get enough blood to function correctly. This can cause cramping, numbness, and feeling cold, especially after challenging physical activity such as climbing stairs.

Doctors often press on the PTA as a way to test for peripheral artery disease.

Peripheral artery disease can be treated with medication and, in advanced cases, minor surgical procedures. If peripheral artery disease in the PTA isn't treated, the lack of blood flow to the leg can cause muscle and other tissue to die, a condition known as gangrene. A body part affected by gangrene often must be amputated.

Untreated peripheral artery disease also increases the risk of heart attack.

Compartment Syndrome

This is a condition in which the calf muscles become inflamed and so swollen they squeeze the artery enough to prevent the smooth flow of blood.

There are several types of compartment syndrome: In exertion or exercise-induced compartment syndrome, swelling occurs after physical activity. In athletes it sometimes can become persistent and is known as chronic compartment syndrome.

Acute compartment syndrome can result from an injury to the leg such as a fracture or serious bruise. It sometimes is a medical emergency.

The symptoms of compartment syndrome include severe pain, numbness, and tingling in the legs and feet that can last from an hour to several days, depending on the cause. In most cases, rest alone will take care of the problem.

If it doesn't, a surgeon can perform a procedure called a fasciotomy. It involves opening up the skin and fascia, tough connective tissue, that surrounds muscles to relieve pressure from swelling.

Summary

The posterior tibial artery plays an important role in supplying blood and oxygen to the muscles and bones in the lower leg. It is a continuation of the popliteal artery, which directly connects to the femoral artery.

Two health conditions can involve the PTA. One is peripheral artery disease, which usually can be treated with medication. The other is compartment syndrome, in which swelling of muscles surrounding the artery interfere with blood flow. Depending on the cause, compartment syndrome can be managed with rest or, in acute cases caused by an injury, surgery.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Mark Gurarie
Mark Gurarie is a freelance writer, editor, and adjunct lecturer of writing composition at George Washington University.

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Source: https://www.verywellhealth.com/posterior-tibial-artery-anatomy-4707725

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