Examine the deep veins from the groin to the ankle.
This technique will examine the common femoral vein (CFV), (superficial) femoral vein (SFV) and popliteal vein (POPV). In the calf, the posterior tibial and peroneal veins (both usually paired) are assessed. The anterior tibial veins are so rarely subject to thrombosis that they are not examined as a matter of routine. If there has been direct trauma to the antero-lateral shin, this area should be examined.
Common Femoral & (Superficial) Femoral Veins
Begin with the patient supine. If possible slightly externally rotate the affected leg. In transverse, high in the groin crease, locate the CFA & CFV at the sapheno-femoral junction. Compress the vein. You should see complete apposition of the vein walls (ie they should touch and the vein compress completely). Be cautious of suggesting thrombus incorrectly due to poor compressibility at valves. Continue to follow the vein sequentially compressing down to the distal thigh. Document the normal anatomy and any pathology found, including doppler images demonstrating flow.
Seat the patient on the side of the bed to help dilate the veins for easier visualisation.
Place the probe transversely at the knee crease in the popliteal fossa. Locate the popliteal artery and vein. Check the compressibility of the popliteal vein throughout the popliteal fossa. Be cautious not to mistake the often prominant muscular veins (gastrocnemius veins) for the popliteal vein. Whislt not truely deep veins they are generally large and still pose a lesser risk of embolisation. As such, you should also examine these as possible causes of the patient’s symptoms.
Patient still seated as above.
Transversely, with the toe of the probe on the medial edge of the mid tibia, locate the paired posterior tibial and peroneal veins.
A common variant is for there to be a single vein instead of a pair. Generally the single vein will be slightly larger than if paired. If you have adequate detail, assess their compressibility along their length. Alternatively, in longitudinal, use colour doppler to confirm their patency.
Common Pathology/ Differential diagnoses
Common differential diagnoses identifiable on ultrasound are:
- Bakers cyst (semi-membranosis-gastrocnemial bursa) in the medial popliteal fossa.
- Superficial venous thrombosis of varices and the long/short saphenous veins.
- Calf muscle tears