Round Ligament of the Uterus

The round ligament of the uterus is a fibromuscular band that extends from the uterine cornu to the labia majora through the inguinal canal. It is a derivative of the embryonic gubernaculum and functions primarily to maintain the anteverted position of the uterus. Though it does not provide strong mechanical support, the round ligament contributes to uterine orientation, especially during pregnancy when it is stretched and displaced. It contains smooth muscle fibers, connective tissue, blood vessels, and nerves.

Structure

The round ligament is a narrow, flattened, fibrous cord that contains bundles of smooth muscle interspersed with connective tissue. It has a core of vascular and lymphatic elements and is covered by peritoneum at its uterine end.

• Length: Approximately 10–12 cm
• Composition: Smooth muscle fibers, fibrous tissue, vessels, and nerves
• Embryologic origin: Gubernaculum

Microscopic Features

• Core of collagen and smooth muscle
• Surrounded by mesothelium at the uterine origin
• Vascularized by small branches from the uterine and inferior epigastric arteries

Location

The round ligament originates at the uterine horn, just below and anterior to the origin of the fallopian tube. It courses laterally within the layers of the broad ligament, then enters the deep inguinal ring, traverses the inguinal canal, and terminates in the subcutaneous tissue of the labia majora.

Function

• Uterine Positioning: Helps maintain the anteverted and anteflexed position of the uterus by anchoring it anteriorly
• Pregnancy Adaptation: Stretches as the uterus enlarges, contributing to round ligament pain
• Embryological Guidance: Remnant of the gubernaculum which guided descent of the ovary during development

Blood Supply

• Arterial: Uterine artery (via branches to the round ligament) and inferior epigastric artery (via cremasteric branch)
• Venous: Veins accompany arteries and drain into uterine and inferior epigastric veins

Lymphatic Drainage

• Superficial inguinal lymph nodes

Innervation

• Autonomic fibers accompanying blood vessels
• Sensory fibers may contribute to round ligament pain during pregnancy

Embryological Development

• Derived from the gubernaculum, which originally connected the developing ovary to the labioscrotal swelling
• In males, the homologous structure is the gubernaculum testis

Clinical Significance

• Round Ligament Pain: Sharp or aching pain during pregnancy due to stretching; typically self-limited
• Endometriosis: May involve the round ligament and mimic inguinal hernia symptoms
• Round Ligament Varicosities: Rare venous engorgement seen in pregnancy, often mistaken for hernia
• Laparoscopic Landmark: Round ligament is often used to help locate the uterus or trace the broad ligament during pelvic surgery