The femoral triangle is an anatomical region of the upper third of the thigh. It is a subfascial space which appears as a triangular depression below the inguinal ligament when the thigh is flexed, abducted and laterally rotated.
The apex of the triangle is continuous with the adductor canal. The roof is formed by the skin, superficial fascia, and deep fascia. The superficial fascia contains the superficial inguinal lymph nodes, femoral branch of the genitofemoral nerve, branches of the ilioinguinal nerve, superficial branches of the femoral artery with accompanying veins, and upper part of the great saphenous vein. The deep fascia has a saphenous opening and the opening is covered by the cribiform fascia. Its floor is formed by the pectineus and adductor longus muscles medially and iliopsoas muscle laterally.
Contents
The femoral triangle is important as a number of vital structures pass through it, right under the skin. The following structures are contained within the femoral triangle :
Lateral cutaneous nerve of thigh - It crosses the lateral angle of the triangle, runs on the lateral side of the thigh and ends by dividing into anterior and posterior branches. The anterior branch supplies the anterolateral aspect of the thigh while the lateral branche supplies the lateral aspect of the gluteal region.
Femoral nerve and its terminal branches - The nerve enters the femoral triangle by passing beneath the inguinal ligament, just lateral to the femoral artery. In the thigh, the nerve lies in a groove between iliacus muscle and psoas major muscles, outside the femoral sheath, and lateral to the femoral artery. After a short course of about 4 cm in the thigh, the nerve is divided into anterior and posterior divisions, separated by lateral femoral circumflex artery.
Nerve to pectineus - This nerve arises from the femoral nerve just above the inguinal ligament. It passes behind the femoral sheath to reach the anterior surface of the pectineus muscle.
Femoral sheath encloses the upper 4 cm of the femoral vessels. Its contents are shown below :
Femoral branch of the genitofemoral nerve - occupies the lateral compartment of the femoral sheath along with femoral artery. It supplies the skin over the femoral triangle.
Femoral artery and its branches - It emerges from the base of the femoral triangle at the mid-inguinal point and exits through the apex of the triangle into the adductor canal.
Femoral vein and its tributaries - The vein lies medial to the femoral artery at the base of the triangle but as it approaches the apex of the triangle, it lies posteromedially to the femoral atery. It receives drainage from great saphenous vein, circumflex veins, and veins corresponding to the branches of the femoral artery here.
Since the femoral triangle provides easy access to a major artery, coronary angioplasty and peripheral angioplasty is often performed by entering the femoral artery at the femoral triangle. Heavy bleeding in the leg can be stopped by applying pressure to points in the femoral triangle. Another clinical significance of the femoral triangle is that the femoral artery is positioned at the midinguinal point ; medial to it lies the femoral vein. Thus the femoral vein, once located, allows for femoral venipuncture.. Femoral venopuncture is useful when there are no superficial veins that can be aspirated in a patient, in the case of collapsed veins in other parts of body. The positive pulsation of the femoral artery signifies that the heart is beating and also blood is flowing to the lower extremity. It is also necessary to appreciate clinically that this is a case where the nerve is more lateral than the vein. In most other cases the nerve would be the deepest or more medial followed by the artery and then the vein. But in this case it is the opposite. This must be remembered when venous or arterial samples are required from the femoral vessels. This area contains the superficial and deep basins of the inguinal lymph nodes, and is the location targeted in an inguinal lymphadenectomy. The basins are separated by the fascia lata. For patients with palpable nodal disease, removal of the superficial and deep basins are recommended. In a patient with a positive sentinel lymph node biopsy, generally only the superficial nodes are removed, unless Cloquet's node is clinically positive.
