critical care medicine
How To Do Femoral Artery Cannulation, Ultrasound Guided
Relevant Anatomy for Femoral Artery Cannulation, US Guided
The femoral artery and vein are accessible within the femoral triangle, which is defined by the inguinal ligament superiorly, the adductor longus muscle medially, and the sartorius muscle laterally. The inguinal ligament is defined as a line drawn between the symphysis pubis and the anterior superior iliac spine. The femoral artery is imaged inferior to the midpoint of the inguinal ligament. The femoral vein is imaged medially adjacent to the artery. With increasing distance from the inguinal ligament, the vein runs under the artery. However, variant orientation of these vessels occurs regularly. The femoral nerve lies lateral to the artery. The femoral artery is large and lies deep. Cannulation requires a steep angle of needle insertion (45°) as well as longer and larger diameter needles and catheters and a catheter-over-guidewire (Seldinger) technique (as compared to radial artery cannulation). The skin insertion site is influenced by both the imaging and the dimensions of the transducer tip. The desired point of femoral arterial impalement is proximal to its bifurcation into the superficial and deep femoral arteries and inferior to the inguinal ligament. Bleeding due to a through-and-through vascular impalement here can be controlled by externally compressing the vessels against the femoral head. The retroperitoneal space lies superior to the inguinal ligament. A through-and-through vascular impalement here causes retroperitoneal bleeding, and external compression of the vessels may be impossible. 