The retrohepatic space is an anatomical area located behind the liver within the abdominal cavity. Understanding this region is relevant for medical professionals and is often discussed in anatomical studies.
Anatomy and Location
The retrohepatic space is a region within the retroperitoneum, the area behind the abdominal lining called the peritoneum. It is defined by its direct relationship with the liver, specifically where the liver is not covered by peritoneum, often termed the “bare area” of the liver.
This space houses structures located in close proximity to the posterior surface of the liver. The inferior vena cava (IVC), a large vein that carries deoxygenated blood from the lower body to the heart, is a prominent structure in this area. It typically runs along the posterior aspect of the liver, with hepatic veins, which drain blood from the liver, directly entering the IVC within this segment.
The intrahepatic IVC, the segment within or immediately behind the liver, typically measures between 3.3 to 8.2 cm in length and 1.5 to 3.0 cm in diameter. The major hepatic veins, including the right, middle, and left hepatic veins, usually number two to four. The middle and left often form a common opening into the IVC. Other smaller veins also connect the liver directly to the IVC in this region.
Importance in Medical Contexts
The retrohepatic space holds significant medical relevance due to the presence of large blood vessels, particularly the inferior vena cava and hepatic veins. Injuries to this area, often from abdominal or pelvic trauma, can lead to substantial internal bleeding (retroperitoneal hematoma). Such bleeding can be life-threatening due to rapid blood accumulation and potential hypovolemic shock.
Surgeons performing liver procedures, such as resections for tumors or transplants, require a detailed understanding of this region. The close proximity of the liver and IVC, coupled with direct hepatic vein drainage, makes surgical maneuvers complex. Tumors originating in the liver or bile ducts can invade the retrohepatic vena cava, complicating surgical removal and increasing risks like massive air embolism or hemorrhage. Knowledge of variations in hepatic vein anatomy is also useful for planning and executing these procedures safely.
Medical conditions like retroperitoneal fibrosis (proliferation of fibrous tissue) or certain infections can affect this space. Pancreatitis, an inflammation of the pancreas, can extend into the retroperitoneum, potentially impacting structures near the retrohepatic area. The concealed nature of this space means symptoms can be non-specific, often leading to delayed diagnosis.
How it is Examined
Medical professionals use various imaging techniques to assess the retrohepatic region. Computed Tomography (CT) scans provide high-resolution images, allowing for the detection of calcifications or gas, and offer rapid acquisition. However, CT scans involve radiation exposure and have limitations in soft tissue characterization.
Magnetic Resonance Imaging (MRI) offers excellent soft tissue contrast without ionizing radiation. MRI is useful for evaluating blood vessels and characterizing soft tissue lesions, providing insights into disease extent. Ultrasound can also be used as an initial imaging modality, especially in acute situations or for guiding interventions, as it is non-invasive and does not use radiation. These imaging methods help identify abnormalities, assess the involvement of surrounding structures, and plan treatment strategies.