Content of the Femoral Sheath

Three Compartments (lateral to medial)

What is NOT in the femoral sheath

• Femoral nerve - it lies lateral to the sheath, outside it, within the muscular lacuna (lacuna musculorum) separated by the iliopectineal arch
• The iliopsoas muscle and lateral femoral cutaneous nerve are also outside, in the lacuna musculorum

Key Anatomical Points

• The iliopectineal arch divides the space beneath the inguinal ligament into:
  • Lacuna vasorum (medial) - contains the femoral sheath and its contents
  • Lacuna musculorum (lateral) - contains iliopsoas, femoral nerve, and lateral femoral cutaneous nerve
• The femoral branch of the genitofemoral nerve passes within the lateral part of the vascular lacuna and may enter the lateral compartment of the femoral sheath

• Cone-shaped, normally contains only loose connective tissue, fat, and lymphatics
• Its proximal opening = femoral ring, bounded by:
  • Anteriorly: inguinal ligament
  • Posteriorly: iliopubic tract / pectineal ligament (Cooper's ligament)
  • Medially: lacunar ligament (Gimbernat's ligament)
  • Laterally: femoral vein
• The femoral ring is sealed by the septum crurale (a plug of extraperitoneal fat)
• Cloquet's node (also called Rosenmüller's node) sits at the femoral ring
• The canal allows the femoral vein to expand during increased venous return

• The femoral canal is the site of femoral hernias - abdominal contents can protrude through the femoral ring down the femoral canal, appearing as a swelling below and lateral to the pubic tubercle
• Femoral hernias are more common in women (due to wider pelvis and thus wider femoral ring)
• The rigid boundaries of the femoral ring (especially the sharp lacunar ligament medially) make femoral hernias prone to strangulation

• The sheath merges with the adventitia of the vessels approximately 4 cm below the inguinal ligament

Contents of the Femoral Sheath

Femoral nerve is NOT inside the sheath - it lies lateral to it, outside the sheath.