Tips for locating lower extremity arteries on ultrasound

26th Feb 2021

Arteries are difficult to identify without labels; however, there are a few tricks to keep you on track while evaluating them. First, there are two easy ways to differentiate between veins and arteries on duplex ultrasound:

  1. Compression (or the lack of compression)
  2. Color

To differentiate arteries from veins on duplex ultrasound, try to compress the vessel. Veins are easily compressible, but arteries are not. 

Veins are also a different color than arteries on color flow duplex ultrasound. Veins are blue while arteries are red. It’s important to note that this color setting can be changed, so be sure to check the ultrasound settings when you start!

Red artery and blue vein on color flow duplex. Ultrasound image.

Figure 1. On color flow duplex ultrasound, arteries appear red while veins appear blue.

Next, let’s cover a few tips and tricks for finding specific lower extremity arteries.

 

Tips for finding the common femoral artery

To find the common femoral artery (CFA) in a transverse view, look for what is referred to as the Mickey Mouse view. It consists of the CFA, the common femoral vein (CFV), and the saphenofemoral junction (SFJ), with the great saphenous vein in the groin.

Mickey Mouse view on duplex. Ultrasound image.

Figure 2. The Mickey Mouse view on a transverse duplex ultrasound consists of the common femoral artery (CFA), the common femoral vein (CFV), and the saphenofemoral junction (SFJ).

When looking for the CFA in a longitudinal view, look for what is commonly referred to as the tuning fork view. The tuning fork view shows the CFA as it bifurcates into the profunda femoris artery (PFA) and superficial femoral artery (SFA) in the groin. 

Tuning fork view on duplex. Ultrasound image.

Figure 3. The tuning fork view on a longitudinal duplex ultrasound consists of the common femoral artery (CFA) bifurcating into the profunda femoris artery (PFA) and superficial femoral artery (SFA).

 

Tips for finding the superficial femoral artery

The presence of the femoral vein helps identify the SFA. In a transverse view, the vein is below the artery on the ultrasound screen. 

Superficial femoral artery (SFA) superior to the femoral vein on transverse duplex. Ultrasound image.

Figure 4. The superficial femoral artery (SFA) is located just above the femoral vein on transverse duplex ultrasound. 

Remember, blue is typically assigned to veins, and red is assigned to arteries on color flow duplex ultrasound. There may be duplicated femoral veins—but they are easy to tell apart from the SFA. As we’ve already covered, not only is the color assignment different, but veins are easily compressible while arteries are not.

Superficial femoral artery (SFA) and femoral vein on transverse color flow duplex. Ultrasound image.

Figure 5. On color flow duplex ultrasound with a transverse view, the femoral vein appears blue and is typically located below the superficial femoral artery (which appears red).

Check out this short video from our Ultrasound Masterclass: Arteries of the Legs Course. In it, you’ll notice that the color flow is displaying the femoral vein in blue below the SFA in red. When the color is turned off, and slight pressure is applied with the probe, you can see how the vein is easily compressed.

 

In a longitudinal view on ultrasound, a healthy SFA appears as an unremarkable tube. It is recognized by its anatomical location along the length of the medial thigh. 

Longitudinal view of the superficial femoral artery (SFA) superior to the femoral vein on color flow duplex. Ultrasound image.

Figure 6. The superficial femoral artery (SFA) on a longitudinal duplex ultrasound is typically positioned above the femoral vein. The artery appears red on color flow while the vein appears blue. 

 

Tips for finding the popliteal artery

In contrast to the other lower extremity vessels, the popliteal vein appears above the artery on the duplex ultrasound screen, for both the longitudinal and transverse views. 

Popliteal vein superior to the popliteal artery on longitudinal, transverse, and color flow duplex ultrasound. Images.

Figure 7. The popliteal artery appears below the popliteal vein in both the longitudinal and transverse views. 

In this short snippet from our Ultrasound Masterclass: Arteries of the Legs Course, you can see how the popliteal vein is compressed with light probe pressure. As color flow is added, note that the red, pulsatile flow in the popliteal artery is below the blue, non-pulsatile flow in the popliteal vein. 

To summarize, to find the CFA, we look for the Mickey Mouse view. To find the SFA, look for the vein underneath the artery. To find the popliteal artery, look for the vein above the artery on ultrasound.

Table showing what to look for to find lower extremity arteries on ultrasound: for the common femoral artery, the Mickey Mouse view; for the superficial femoral artery, vein is below artery; for the popliteal artery, the artery is below the vein.

Table 1. What to look for on duplex ultrasound to find the common femoral artery (CFA), superficial femoral artery (SFA), and popliteal artery. 

 

 

Tips for finding the anterior tibial artery and the tibioperoneal trunk

To find the anterior tibial artery (ATA) and the tibioperoneal trunk (TPT), keep moving the probe down the patient’s leg. The distal popliteal artery can be seen as it bifurcates into the ATA and TPT, with the popliteal vein above the artery.

 

Popliteal artery bifurcation into the anterior tibial artery (ATA) and tibioperoneal trunk (TPT) below the popliteal vein on color flow duplex. Ultrasound image.

Figure 8. The popliteal vein is located above the arteries on color flow duplex ultrasound when the popliteal artery bifurcates into the anterior tibial artery (ATA) and tibioperoneal trunk (TPT). 

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Tips for finding the dorsalis pedis artery

The calf arteries at the ankle are the dorsalis pedis artery (DPA) and the posterior tibial artery (PTA). They are very small arteries that can be identified by two or more compressible deep veins traveling parallel to them. 

To find the DPA, place the probe on the anterior ankle and move laterally. If you have trouble finding the artery, try following the same path as an ankle-brachial index (ABI) Doppler pen by starting between the bones of the first two toes and moving proximally. On ultrasound, the DPA will appear very superficial with calcific shadowing underneath, which is caused by an underlying bone.

Dorsalis pedis artery (DPA) on color flow duplex ultrasound in a longitudinal view. Image.

Figure 9. The dorsalis pedis artery (DPA) can be found by placing the probe on the anterior ankle. The DPA will appear superficial with calcific shadowing underneath, which is caused by an underlying bone.

Check out this short video demonstrating a color flow duplex ultrasound of the DPA from our Ultrasound Masterclass: Arteries of the Legs Course:

If you are unable to find the pedal pulses while doing ABIs, you can use duplex ultrasound at the ankle to visualize the arteries and confirm an occlusion.

 

 

Tips for finding the posterior tibial artery

Similar to the Doppler pen, you can find the PTA behind the medial malleolus. If you cannot see the PTA very well, perform a distal augment, which is a squeeze of the foot. Blood flow in the vein is accelerated by squeezing distally. The veins can be identified by a blue flash on the duplex created by the blood movement. Where there is a vein, an artery is nearby. 

Blue flash in a vein close to the posterior tibial artery (PTA) created with a distal augment in a color flow duplex. Ultrasound image.

Figure 10. To view the posterior tibial artery (PTA) in a transverse view, squeeze the foot, and look for a blue flash created by the movement of blood in the nearby vein.

In this video from our Ultrasound Masterclass: Arteries of the Legs Course, you can see the PTA pulsing red and a blue flash elicited in the nearby vein from a distal augment:

 

The PTA is also superficial and can be easily seen at the ankle level—especially because of the two or more accompanying veins. 

Posterior tibial artery (PTA) on color flow duplex ultrasound in a longitudinal view. Image.

Figure 11. The posterior tibial artery (PTA) is easy to find because it is superficial and is located beside two or more veins. 

Check out this short video from our Ultrasound Masterclass: Arteries of the Legs Course demonstrating the PTA pulsing red on a longitudinal color flow duplex ultrasound:

 

That’s it for now. If you want to improve your understanding of key concepts in medicine, and improve your clinical skills, make sure to register for a free trial account, which will give you access to free videos and downloads. We’ll help you make the right decisions for yourself and your patients.

Recommended reading

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