Femoral Triangle

Overview

The femoral triangle (Scarpa’s triangle) is a inverted triangular-shaped subfascial space located within the superomedial aspect of the anterior thigh, which acts as a conduit for neurovascular structures passing from the pelvis to the upper thigh. It corresponds to the depression seen immediately below the fold of the groin.

Borders

The inguinal liagment acts as a flexor retinaculum

• Roof – deep fascia (fascia lata), superficial fascia and skin
• Floor (medial to lateral) – pectineus, iliopsoas, adductor brevis (occassionally), adductor longus muscle
• Superior border (base) – inguinal ligament
• Lateral border – medial border of the sartorius muscle
• Medial border – medial border of the adductor longus muscle
• Apex – continous with the adductor canal

Contents

Lateral to medial:

• Lateral cutaneous nerve of thigh (lumbar plexus roots L2-L3) – Crosses the lateral angle of the triangle, runs on the lateral side of the thigh and terminates as anterior and posterior branches. The anterior branch supplies the anterolateral aspect of the thigh while the lateral branch supplies the lateral aspect of the gluteal region.
• Femoral nerve (including terminal branches) – Lies in a groove between iliacus 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. Innervates the anterior compartment of the thigh, and provides sensory branches for the leg and foot.
  • Nerve to pectineus – 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 (floor of femoral triangle)

Femoral Sheath

The femoral (crural) sheath is a continuation of the abdominal fascia that is contained in the femoral triangle. It is made up of three compartments:

• Lateral Compartment
  • 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 – Arises at the mid-inguinal point (midpoint between the anterior superior iliac spine and the pubic symphysis) and exis through the apex of the triangle into the adductor canal. It provides the majority of the arterial supply to the lower limb.
• Intermediate Compartment
  • Femoral vein – 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 artery. It receives drainage from great saphenous vein, circumflex veins, and veins corresponding to the branches of the femoral artery. Approximately divides the femoral triangle vertically.
• Medial Compartment
  • Femoral canal – a 1.25 cm conical canal that contains deep lymph nodes and vessels. It is is bordered:
    • Anterosuperiorly by the inguinal ligament
    • Posteriorly by the pectineal ligament lying anterior to the superior pubic ramus
    • Medially by the lacunar ligament
    • Laterally by the femoral vein
  • Deep inguinal lymph nodes – It lies deep to the deep fascia, medial to the upper part of the femoral vein, inside the femoral canal (medial compartment of the femoral sheath). Cloquet’s node (also known as Rosenmuller’s node) also lies in this canal. It receives lymphatic drainage from superficial inguinal lymph nodes, lymphatic drainage from the glans penis or clitoris, and from the deep lymphatics of the lower limb

The superficial fascia contains:

• Superficial inguinal lymph nodes
• Femoral branch of the genitofemoral nerve
• Branches of the ilioinguinal nerve
• Superficial branches of the femoral artery
• Superficial branches of the femoral vein
• Upper part of the great saphenous vein

The deep fascia has a saphenous opening and the opening is covered by the cribiform fascia.