Hepatic Lobar Agenesis

After birth, possibly because of abrupt termination of the oxygenated umbilical venous inflow, the left lobe shrinks considerably so that the fetal lateral segment often comes to be located closer to the midline than the fetal medial segment. However, by convention, the fetal nomenclature for these segments is maintained after birth. The ligamenta teres and venosus lie within fissures that separate the left medial and lateral segments and the caudate lobe. Location of the liver can be abnormal, with one or more segments hypoplastic or absent36-38 (Fig. 2-26). Occasionally, the right rather than the left

Fig. 2—24. Perforation of Meckel's diverticulum in a

12-year-old male who presented with abdominal pain and vomiting.

(a) Abdominal radiograph shows an air-filled dilatation of small bowel loops (curved arrows) and gas bubbles in the peritoneal cavity (arrows).

(b and c) CT shows a part of il-eum with thickening of its wall (straight arrows) with surrounding intraperitoneal gas bubbles (curved arrows).

Emergency surgery revealed a perforation of an inflamed Meckel's diverticulum containing ectopic gastric mucosa.

Ectopic Liver Tissue Radiology

Fig. 2-25. Ectopic liver tissue with malignancy.

Longitudinal sonogram in a patient with cirrhosis shows a large soft tissue mass (M) between the liver (L) and right kidney (K). At autopsy, the mass proved to be hepatocellular carcinoma that was entirely separate from the liver, having likely developed within ectopic liver tissue.

Fig. 2-25. Ectopic liver tissue with malignancy.

Longitudinal sonogram in a patient with cirrhosis shows a large soft tissue mass (M) between the liver (L) and right kidney (K). At autopsy, the mass proved to be hepatocellular carcinoma that was entirely separate from the liver, having likely developed within ectopic liver tissue.

umbilical vein persists, in which case the ligamentum teres fissure may be located to the right of the gallblad-der.39 Variations of the usual branching of the hepatic vasculature are common and of great significance for liver surgeons.40 Although the hepatic and portal veins are the anatomic basis for delineating the segmental anatomy of the liver,41,42 recent work has questioned the accuracy of imaging studies in correctly localizing focal lesions.43

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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