Liver segment III !
Liver segment III is the lower front part of the left liver, under the left ribs and the upper belly, to the left of the round ligament.
Official name: Left anterior lateral segment of liver
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What it is
Liver segment III: the lower part of the left lateral lobe.
What it does
Because each segment has its own supply, surgeons can remove one or more segments and leave the rest working.
Key facts
- Where
- Left lateral section, inferior (anterior) part, left of falciform ligament and umbilical fissure
- Blood supply
- Branch of left portal vein (umbilical part) and left hepatic artery; drains into left hepatic vein
- Nerve
- Hepatic plexus (celiac sympathetic and vagal fibres) along its portal pedicle, shared with the whole liver
- Function
- Independent surgical unit; bile to left hepatic duct; segment III duct is a classic bypass target for hilar obstruction
Relations
- In front
- Anterior abdominal wall below the xiphoid process and the left costal margin
- Medial
- Falciform ligament and round ligament of the liver in the umbilical fissure, which separate it from liver segment IV
- Below
- Visceral surface resting on the stomach (gastric impression) and the lesser omentum
- Behind
- Liver segment II, behind and above
How to find it
The lowest, most anterior part of the left liver, under the epigastrium and the left costal margin just left of the falciform ligament; it is usually the first part of the liver seen through an upper midline incision.
On imaging
On ultrasound it is well seen through the subxiphoid window; on axial CT or MRI it lies left of the umbilical fissure on the slices below the left portal vein, in front of and below segment II.
Common problems
- Fatty liver disease, very common with obesity and diabetes.
- Hepatitis (viral, alcohol).
- Cirrhosis: scarring that can lead to liver failure and portal hypertension.
- Liver cancer and metastases.
How it is diagnosed
Blood tests (liver enzymes), ultrasound, elastography, CT or MRI, biopsy.
Treatment
- Treat the cause (weight loss, antiviral medicines, stopping alcohol); surgery to remove segments; liver transplant for failure.
Clinical notes
- The resection line of a left lateral sectionectomy runs just left of the falciform ligament
- Grafts for infants may be reduced to a single segment (III or II) when a whole left lateral section is too large
- Ultrasound-guided biopsy or drainage of the left liver is usually done from below the xiphoid process, with the needle entering the left lateral section, often segment III
Development
The round ligament beside it is the remnant of the left umbilical vein, which in the fetus joined the umbilical portion of the left portal vein that still feeds segments III and IV.
Test yourself
Think of the answer, then tap the question to see it.
Where does liver segment III get its portal supply?
From the umbilical portion of the left portal vein, which also feeds segment IV, so dissection in the umbilical fissure can endanger both.
What separates liver segment III from liver segment IV?
The falciform ligament and round ligament of the liver in the umbilical fissure.
Why is the liver segment III duct a classic surgical target?
It is a bypass target for hilar bile duct obstruction.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- segmentum anterius laterale sinistrum hepatis TA2 3069
- Official Spanish (DeCS)
- Segmento III del hígado DeCS D008099
- English (TA2)
- Left anterior lateral segment of liver
- Also called
- segment III of liver
Sources: Terminologia Anatomica (TA2); DeCS; Diagnostic Imaging of the Liver; Anatomy, Abdomen and Pelvis: Liver; 23.6 Accessory Organs in Digestion: The Liver, Pancreas, and Gallbladder (OpenStax (Rice University), 2022) · adapted, CC BY 4.0.
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Representative model, for educational purposes only.
