Falciform ligament
The falciform ligament is a thin, sickle-shaped fold of peritoneum that attaches the liver to the anterior abdominal wall and diaphragm. It serves as an important anatomical landmark and contains structures of clinical significance, including the ligamentum teres hepatis.
Anatomy of the Falciform Ligament
Location and Boundaries
The falciform ligament is located in the anterior aspect of the abdominal cavity, extending from the inferior surface of the diaphragm to the anterior abdominal wall. Its boundaries include:
- Superior Boundary: Diaphragmatic surface of the liver
- Inferior Boundary: Anterior abdominal wall at the level of the umbilicus
- Anterior Boundary: Inner surface of the anterior abdominal wall
- Posterior Boundary: Liver segments IV and III
Relations
The falciform ligament has important relations with surrounding structures:
- Anteriorly: Parietal peritoneum of the anterior abdominal wall
- Posteriorly: Liver, separating the left and right lobes partially
- Superiorly: Diaphragm
- Peritoneal cavity: Forms a reflection contributing to the anterior peritoneal recess
Structure
The falciform ligament is composed of two layers of peritoneum enclosing connective tissue. Its contents include:
- Ligamentum Teres Hepatis: Remnant of the fetal umbilical vein running in the free edge of the ligament
- Fat and connective tissue providing structural support
- Small blood vessels and lymphatic channels
Embryology and Development
Formation from the Ventral Mesentery
The falciform ligament develops from the ventral mesentery during embryogenesis. Initially, it connects the developing liver to the anterior abdominal wall and diaphragm, providing structural support during organ growth.
Relation to Fetal Circulation
Within the fetal falciform ligament runs the umbilical vein, which carries oxygenated blood from the placenta to the liver. This vein forms the precursor to the ligamentum teres hepatis after birth.
Transformation Postnatally
Following birth, the umbilical vein closes and fibroses, transforming into the ligamentum teres hepatis. The falciform ligament remains as a peritoneal fold, maintaining its attachments to the liver and anterior abdominal wall.
Physiological Role
Support of the Liver
The falciform ligament provides partial support to the liver, stabilizing it within the anterior abdominal cavity and limiting excessive movement during respiration or physical activity.
Pathway for Vessels and Ligaments
The ligament serves as a conduit for small vessels, lymphatic channels, and the ligamentum teres hepatis, ensuring continuity of blood and lymph flow within the anterior hepatic region.
Contribution to Peritoneal Reflections
As a double layer of peritoneum, the falciform ligament contributes to the complex network of peritoneal reflections and recesses in the anterior abdominal cavity, aiding in compartmentalization and organization of the viscera.
Clinical Significance
Falciform Ligament Pathologies
Although rare, the falciform ligament can be involved in several pathological conditions:
- Cysts and Tumors: Benign or malignant masses may develop within the ligament, occasionally causing abdominal discomfort or obstruction.
- Ligamentous Thickening or Calcification: Age-related changes or prior inflammation can lead to thickening or calcification, which may be identified incidentally on imaging.
- Internal Hernias: Rarely, loops of bowel may herniate around the falciform ligament, leading to obstruction and requiring surgical intervention.
Surgical Considerations
The falciform ligament is an important landmark during abdominal and hepatic surgeries:
- Identifying the ligament helps orient surgeons to the anterior hepatic surface and the location of the ligamentum teres hepatis.
- In laparoscopic procedures, care must be taken to avoid injury to the ligament and its contained structures.
- Resection or mobilization of the ligament may be performed to improve surgical exposure of the liver or anterior abdominal structures.
Imaging and Diagnosis
Ultrasound Appearance
On ultrasonography, the falciform ligament appears as a thin echogenic line extending from the anterior abdominal wall to the liver. The ligamentum teres hepatis may be seen as a hypoechoic tubular structure within the ligament.
CT and MRI Evaluation
Computed tomography and magnetic resonance imaging provide detailed visualization of the falciform ligament, allowing assessment for masses, thickening, or calcifications. These modalities are particularly useful in preoperative planning and evaluation of abdominal pathology.
Diagnostic Importance in Abdominal Pathology
Recognizing the falciform ligament on imaging is essential to differentiate normal anatomical structures from pathological findings such as peritoneal tumors, cysts, or internal hernias. Proper identification can guide surgical and therapeutic decision-making.
Comparative Anatomy
Variations Among Species
The falciform ligament is present in many vertebrates, although its size and structure vary among species. In quadrupeds, it often provides significant support to the liver and may contain larger amounts of fat or connective tissue compared to humans.
Evolutionary Significance
The falciform ligament reflects an evolutionary adaptation for stabilizing the liver within the abdominal cavity. Its persistence in mammals provides a structural pathway for the umbilical vein in fetal life and maintains continuity of peritoneal folds in the adult.
References
- Standring S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. London: Elsevier; 2020.
- Drake RL, Vogl AW, Mitchell AWM. Gray’s Atlas of Anatomy. 2nd ed. Philadelphia: Elsevier; 2021.
- Moore KL, Persaud TVN, Torchia MG. The Developing Human: Clinically Oriented Embryology. 11th ed. Philadelphia: Elsevier; 2020.
- Skandalakis JE, Gray SW. Surgical Anatomy: The Embryologic and Anatomic Basis of Modern Surgery. 4th ed. New York: Springer; 2018.
- Standring S, Ellis H. Surgical Anatomy of the Abdomen and Pelvis. London: Elsevier; 2019.
- Netter FH. Atlas of Human Anatomy. 7th ed. Philadelphia: Elsevier; 2021.
