The femoral triangle and the front of the thigh

1. Boundaries

The femoral triangle lies just below the groin crease. Its roof is fascia; its borders are the inguinal ligament above, the sartorius laterally and the adductor longus medially.

Surgeon’s corner: Femoral hernias come out below the inguinal ligament, medial to the femoral vein. They often strangulate because the femoral canal is narrow.

2. Contents: NAVeL

From lateral to medial: femoral Nerve, femoral Artery, femoral Vein, and the empty space of the femoral canaL with its lymph node. The artery lies at the mid-inguinal point, halfway between the anterior superior iliac spine and the pubic symphysis.

Surgeon’s corner: For arterial access you puncture over the femoral head, below the inguinal ligament: too high and you cannot compress the puncture (retroperitoneal bleeding), too low and you hit the bifurcation.

3. Deep femoral artery and circumflex arteries

About 4 cm below the inguinal ligament the deep femoral artery leaves the femoral artery laterally and backwards. Its medial and lateral circumflex branches wrap around the top of the femur; perforating branches feed the thigh muscles.

Surgeon’s corner: The ascending branch of the lateral circumflex femoral artery crosses the interval in the direct anterior approach to the hip and is ligated there.

4. Nerves of the front of the thigh

The femoral nerve fans out to the quadriceps and the skin of the front of the thigh, and gives the saphenous nerve, which continues down to the medial leg. Lateral to it, the lateral femoral cutaneous nerve runs under the inguinal ligament near the anterior superior iliac spine.

Surgeon’s corner: The lateral femoral cutaneous nerve is the nerve you damage in the anterior hip approach (numb lateral thigh) and the cause of meralgia paraesthetica from tight belts.