Although needle access to the femoral artery is most simply performed with palpation, in situations where this is limited (e.g. weak pulses due to atherosclerotic disease? obesity?), ultrasound could easily be used for guidance.
In the old days before readily available high-frequency ultrasound, however, fluoroscopic landmarks were used to help guide puncture in more challenging situations. The most stable landmark is the relationship of the common femoral artery overlying the medial femoral head (below). In one study, the center line of the common femoral artery projected over the medial half of the femoral head in 93% of patients (medial third in 69%, medial to the femoral head in 6%). One source suggests an initial puncture 1 cm lateral to the most medial cortex of the femoral head as the best site for both retrograde and anterograde femoral artery puncture.
This landmark is also useful in that it is above the femoral artery bifurcation and below the inguinal ligament. Puncture of the external iliac artery above the inguinal ligament is associated with significantly higher bleeding complications. Distal SFA punctures are associated with a greater risk of dissection and thrombosis, increased risk of hematoma and pseudoaneurysm, and an increased risk of AVF. A puncture over the femoral head also aids in compression and cessation of bleeding after removing the sheath.
Other points to remember are that calcifications in the arteries can be used to help determine where the lumen is, and that the landmarks mentioned above are critically dependent on normal AP orientation, and deviation from the normal AP orientation can result in a large change in position of the artery relative to the femoral head.
The flip side of recognizing fluoroscopic landmarks is to avoid the vascular structure when making a puncture to access the hip joint space.
Ultrasound guidance is probably prudent in anticoagulated patients with a difficult access approach (obesity, scar, hematoma). The vessel should be punctured as centrally as possible.
1. Dotter CT, Rosch J, Robinson M. "Fluoroscopic Guidance in Femoral Artery Puncture" Radiology 127:266-267, April 1978
2. Wacker F, Wolf KJ, Fobbe F. "Percutaneous vascular access guided by color duplex sonography" Eur Radiol. 1997;7:1501-1504.
3. Rutherford's Vascular Surgery. Cronenwett and Johnston. 7th ed. (2010)