Hypogastrium

HYPOGASTRIUM represents the lower part of the abdominal cavity, which projects onto the anterior abdominal wall. This region is located below the horizontal plane drawn through the highest points of the iliac crests; its lower boundaries are the inguinal ligaments and the pubic symphysis. By two vertical lines drawn through the midpoints of the inguinal ligaments, the hypogastrium is divided into three regions: the middle—pubic region—and two paired lateral ones: the right and left inguinal regions. All this conventional division, just as for other regions of the abdomen, offers convenience in describing clinical examination data. The shape of the hypogastrium, as well as the shape of the entire abdomen, exhibits significant differences in various subjects depending on the development of the muscles and the subcutaneous adipose tissue of the abdominal wall. With normally developed musculature and normal fat deposition, the hypogastrium, most convex in its upper part, gradually flattens downwards and at the lower-middle border turns again into the mons pubis elevation. In obese subjects, as well as in multiparous women with relaxed abdominal musculature, protruding folds of skin form above the inguinal ligaments in the standing position. Special clinical interest is presented by the structure of the abdominal wall of the inguinal regions in connection with the formation of inguinal hernias here. The weakest spot is the inguinal triangle. Above, it is bounded by a horizontal straight line beginning at the transition of the lateral third of the inguinal ligament to the middle third, medially by the lateral edge of the rectus abdominis muscle, and below by the medial two-thirds of the inguinal ligament. In this area, there is no powerful muscle layer of the external oblique abdominal muscle, which passes at the lateral edge of the triangle into its aponeurosis (see Abdominal wall). Furthermore, the abdominal wall bulges here during the descent of the testes and the descent of the ovaries (Corning). According to Venglovsky, the shape of the inguinal interstice, i.e., the space between the lower edge of the internal oblique and transverse abdominal muscles, the inguinal ligament, and the outer edge of the rectus muscle, depends on the site of passage of the gubernaculum testis and testicle in the embryonic period. When they pass through the abdominal wall closer to the midline, the inguinal interstice will be shorter, and the internal oblique muscles will attach to the inguinal ligament at a greater distance. The lower edge of the muscles is often located almost parallel to the ligament, and then the inguinal interstice has an oval shape. When the inguinal cord passes further from the midline, the inguinal interstice is longer. If at the same time the free lower edge of the internal oblique muscles runs almost transversely and passes onto the rectus muscle, lying high from the pubic tubercle, the inguinal interstice has a triangular shape. The formation of inguinal hernias is closely related to the shape and size of the inguinal interstice. The contents of the hypogastrium are subject to significant variations in view of the usual greater or lesser mobility of the organs located here. Usually, in the right part of the hypogastrium lies the cecum with the appendix and the cecal part of the ileum, in the left part the sigmoid colon is located, and in the middle part is the rectum. The space between these organs is filled with loops of the small intestines. With a narrow inferior thoracic aperture and a relatively wide pelvis, the M-shaped curved transverse colon is also often found in the hypogastrium (Pavlenko). The urinary bladder upon its filling rises above the symphysis and is detected in the pubic region. Hypogastric reflex—see Abdominal reflexes.