The medial umbilical fold is an anatomical feature on the inner surface of the anterior abdominal wall. Unlike the median umbilical fold, which contains the remnant of the urachus, the medial umbilical folds contain remnants of the fetal umbilical arteries.
Location
The medial umbilical folds are located on the inner (posterior) side of the lower anterior abdominal wall, on either side of the median umbilical fold. Each fold extends from the umbilicus (navel) downward to the pelvis. They are situated closer to the midline than the lateral umbilical folds, which contain the inferior epigastric vessels.
Structure
The medial umbilical folds are made up of several layers:
- Peritoneal Covering: Like other abdominal folds, they are covered by a layer of peritoneum, which is the lining of the abdominal cavity.
- Fibrous Core: Inside each fold lies the obliterated umbilical artery, which, after birth, becomes a fibrous structure known as the medial umbilical ligament.
- Bilateral Presence: There are typically two medial umbilical folds, one on each side of the median umbilical fold, reflecting the bilateral nature of the umbilical arteries during fetal development.
The appearance of the medial umbilical folds can vary among individuals and may be more prominent in some due to differences in body composition, age, and other factors. Typically, these structures are internal and are not visible or palpable through the skin but can be observed during surgical procedures or on imaging studies.
Function
The medial umbilical folds themselves do not perform any active physiological functions in adults. Their significance lies primarily in their embryological origins and their role as anatomical landmarks:
- Embryological Remnants: The medial umbilical folds contain the obliterated umbilical arteries, which, during fetal development, carried deoxygenated blood from the fetus to the placenta. After birth, these arteries become fibrotic and nonfunctional, known as the medial umbilical ligaments.
- Anatomical Landmarks: In clinical practice, especially in surgeries and radiological examinations, the medial umbilical folds serve as important landmarks. They help in identifying and navigating the anatomy of the lower abdominal and pelvic regions. Knowing the location of these folds allows surgeons to avoid vital structures such as the bladder and major blood vessels during procedures.
Clinical Significance
While the medial umbilical folds themselves do not have significant physiological functions post-birth, they are of clinical and surgical relevance:
- Associated Pathologies: Although rare, pathological conditions can affect the structures contained within the medial umbilical folds, such as aberrant vessels or unusual fibrous bands. Knowledge of these folds is important for diagnosing and managing such conditions.
- Surgical Reference: In procedures like laparoscopic hernia repair or pelvic surgeries, the identification of medial umbilical folds helps in orienting the surgeon and in preserving important structures like the inferior epigastric vessels, which lie in the lateral umbilical folds.
