Liver Anatomy (Function, Topography, External Structures, Ligaments)

Liver Function and Portal System
📌 The Liver is the largest internal organ, weighing approximately 1.5 kilograms, and is primarily located on the right side of the abdomen.
💧 Its main function is to filter blood coming from the digestive tract via the portal system before sending it to systemic circulation through the inferior vena cava.
🧪 The Liver also detoxifies substances like drugs and alcohol, produces cholesterol (used for hormones and vitamin D), and stores nutrients like glycogen.

Liver Topography (Position)
📍 Holotopically, the Liver covers the upper abdominal cavity within the ribs, specifically in the right hypochondriac region, epigastric region, and extending to the left hypochondriac region.
🦴 Skeletopically, the superior border generally aligns with the 4th intercostal space near the right midclavicular line, and the inferior border relates to the 8th-9th ribs on the right side.
🤝 Syntopy shows the superior (diaphragmatic) surface contacts the diaphragm, while the inferior (visceral) surface is adjacent to organs like the pylorus, duodenum, colon, and right kidney.

External Structures and Lobes
❇️ The Falciform Ligament separates the right and left lobes when viewed anteriorly.
⚫ The posterior surface features three important grooves: the Right Sagittal Groove (formed by the gallbladder fossa and the Inferior Vena Cava groove) and the Left Sagittal Groove (formed by the Ligamentum Teres and Ligamentum Venosum).
↔️ The Transverse Groove (porta hepatis) separates the caudate lobe from the quadrate lobe and serves as the entry/exit point for neurovascular structures and hepatic ducts.
🔬 Anatomically, the Liver has two lobes anteriorly but four lobes when considering the posterior view divisions; this differs from the Couinaud's system which divides it into eight functionally independent surgical segments.

Porta Hepatis and Coverings
🩸 The Porta Hepatis is a depression where the common hepatic duct, hepatic portal vein, and hepatic artery proper enter/leave, all covered by the Hepatoduodenal Ligament.
🛡️ The Liver is covered by the Tunica fibrosa (fibrous sheath) and the visceral Peritoneum (Tunica serosa), which reduces friction with surrounding structures.
🚫 The Bare Area (area nuda) is the only location on the posterior margin not covered by the peritoneum/fat, being in direct contact with the diaphragm.

Liver Ligaments
🔗 Ligaments connecting the Liver to the diaphragm include the Falciform Ligament (anteriorly) and the Coronary Ligament (which encircles the Bare Area), along with the Left and Right Triangular Ligaments.
⬅️ Four ligaments originate from the porta hepatis connecting to other organs: Hepatogastric, Hepatoduodenal (containing vessels/ducts), Hepatorenal (to the right kidney), and the Round Ligament of the Liver (remnant of the left umbilical vein).

Key Points & Insights
➡️ The Liver is the body's largest internal organ, central to filtering blood from the digestive tract via the portal vein system.
➡️ Understand the anatomical divisions (anterior vs. posterior lobes) and the functional divisions (Couinaud's 8 segments) for comprehensive knowledge, especially relevant for potential surgery.
➡️ The Porta Hepatis is the critical entry/exit structure containing the hepatic portal vein, artery, and bile ducts, protected within the Hepatoduodenal Ligament.
➡️ The Bare Area is a significant anatomical feature on the posterior surface, lacking peritoneal covering and being in direct contact with the diaphragm.

📸 Video summarized with SummaryTube.com on Feb 08, 2026, 13:31 UTC