Femoral Ring

anulus femoralis

The femoral ring is the superior opening of the femoral canal, bounded anteriorly by the inguinal ligament, medially by the lacunar ligament, laterally by the femoral vein, and posteriorly by the pectineal ligament and pectineus muscle. It is normally filled with fat and a lymph node (Cloquet's node) and is the entry point for femoral hernias.

Anatomical Data

Boundaries & Contents

Location	Upper opening of the femoral canal, just below and behind the medial part of the inguinal ligament
Boundaries	Inguinal ligament (front) Lacunar ligament (medial) Pectineal ligament (back) Femoral vein (lateral)
Contents	Femoral septum of extraperitoneal tissue closing it Lymphatic vessels Lymph node of Cloquet in some people

Biomechanics

Function & Actions

The mouth of the femoral canal. Its sharp, rigid medial edge (lacunar ligament) is why femoral hernias strangulate readily.

Clinical Relevance

Clinical Notes

The femoral ring is smaller in women than men, explaining the higher incidence of femoral hernias in females. A femoral hernia passes through the ring into the femoral canal and presents below the inguinal ligament medial to the femoral pulse. The ring is at risk during medial thigh approaches and femoral vessel cannulation. Cloquet's lymph node at the ring is a sentinel node for lower limb and perineal malignancy.

Pathology

Common Injuries & Conditions

Femoral Hernia

Peritoneal protrusion through the femoral ring producing a medial upper thigh bulge below the inguinal ligament, at high risk of strangulation due to the rigid ring boundaries.

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