Femoral Triangle Contents
The femoral triangle is the key vascular region of the anterior thigh. Its contents — femoral nerve, artery, vein, and lymphatics — lie in a predictable lateral-to-medial sequence under the inguinal ligament, forming the most important access route for cardiac catheterisation and central venous cannulation.
✦ The Mnemonic
"Navigators Always Verify Landmarks"
Lateral to medial: Nerve, Artery, Vein, Lymphatics (empty space then lymphatics)
Clinical Breakdown
The triangle's boundaries are: superiorly the inguinal ligament (ASIS to pubic tubercle), medially adductor longus, and laterally sartorius. The floor is formed by iliopsoas (laterally) and pectineus (medially). The femoral sheath encloses the artery, vein, and femoral canal — but NOT the femoral nerve, which lies outside the sheath under the fascia iliaca.
The midinguinal point (midpoint between ASIS and symphysis pubis) overlies the femoral artery. This is distinct from the mid-inguinal point (midpoint between ASIS and pubic tubercle), which marks the deep inguinal ring. The femoral pulse is palpated and compressed here to control haemorrhage.
Femoral hernia: abdominal contents herniate through the femoral canal (medial compartment of the femoral sheath). Femoral hernias are more common in women (wide femoral canal), appear below and lateral to the pubic tubercle, and are at high risk of strangulation. Treatment is always surgical — the neck of the femoral canal is rigid.
⭐ Clinical Pearl
NAVY (Nerve, Artery, Vein + Y-front = Lymphatics) is another aide-memoire for the femoral triangle lateral-to-medial sequence. In practice, the vein lies very close to the artery — during femoral venous cannulation, aim medial to the pulse. Inadvertent femoral arterial puncture during venous access requires 10+ minutes of sustained compression to achieve haemostasis.
⚠ Exam Trap
Femoral vs inguinal hernia: inguinal hernias appear above and medial to the pubic tubercle; femoral hernias below and lateral. An inguinal hernia can be direct (through Hesselbach's triangle — medial to inferior epigastric vessels) or indirect (through the deep inguinal ring — lateral to epigastric vessels). The femoral canal is entirely separate from the inguinal canal.