Pathways of Ascitic Flow

The transverse mesocolon, small bowel mesentery, sigmoid mesocolon, and the peritoneal attachments of the ascending and descending colon clearly serve as watersheds directing the flow of ascites (Fig. 4-105b). The force of gravity operates to pool peritoneal fluid in dependent peritoneal recesses. Fluid in the inframesocolic compartments preferentially seeks the pelvic cavity. From the left infracolic space, some fluid is temporarily arrested along the superior plane of the sigmoid meso-colon but gradually channels into the pelvis. From the right infracolic space, spread occurs along the small bowel mesentery. It is not until a pool is formed at the apex, at the termination of the ileum with the cecum, that some fluid begins to overflow into the pelvis. The pouch of Douglas is first filled and then, symmetrically, the lateral paravesical recesses (Fig. 4-106). From this point, the fluid ascends both paracolic gutters. Passage up the shallower left one is slow and weak, and cephalad extension is limited by the phrenicocolic gutter. The major flow from the pelvis is up the right paracolic gutter. It continues to the right subhepatic and right subphrenic spaces. The right paracolic gutter serves also as the main communication from the upper to the lower abdominal compartments. Freely movable fluid collecting in the right upper quadrant also continues to be redirected downward along this channel to the pelvis.

Four predominant sites in the lower abdomen are therefore identified clearly as the preferential, repeated, or arrested flow of ascitic fluid: (a) the pelvic cavity, particularly the pouch of Douglas; (b) the right lower quadrant at the termination of the small bowel mesentery; (c) the superior aspect of the sigmoid mesocolon; and (d) the right paracolic gutter. These pathways are illustrated in Fig. 4-105b.

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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