Ligamentum Teres Fissure Sign

Another distinctive sign of pneumoperitoneum is free air confined in the intrahepatic fissure for the ligamen-tum teres. It appears on supine films as a small but sharply defined vertically oriented slitlike or ovoid lu-cency projecting upon the medial half of the right upper quadrant4 (Figs. 7-25 and 7-26). The fissure for the ligamentum teres is a crevice in the liver that contains fat, the ligament itself, and a variable protrusion of peritoneum. It is situated anterior and superior to the gastro-duodenal junction. Consequently, gas liberated from the duodenal lumen by a perforated anterior ulcer often collects in this intrahepatic peritoneal recess.

The ligamentum teres fissure sign is very sensitive, and even less than 1 mL of air trapped within this narrow space can be clearly delineated. The reason for such a high sensitivity is based on the particulars of its anatomy.

The fissure is oriented anteroposteriorly, parallel to the x-ray beam on supine film. The ligamentum teres fissure sign may be the only manifestation of pneumoperito-neum, but more often there is air in other locations superimposed on the liver shadow.

Fat within the fissure, normally seen in 30% of pa-tients33 (Fig. 7-27), and air in the common bile duct may mimic this sign, but they are easily distinguishable. However, a tiny amount of free air occupying only a portion of this peritoneal recess (Fig. 7-28) cannot be differentiated from a small collection of pneumobilia in the left hepatic duct (Fig. 7-29).

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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