Understanding human and pelvic anatomy is essential to the fundamental knowledge of an obstetrician/gynecologist. The basic facts and anatomic structures do not change, but our knowledge and understanding of relationships and function continues to increase. Advances in surgical techniques continue to place more importance on a physician's understanding of surgical landmarks. There can be significant variation in surgical anatomy, so the practitioner should be well versed in "normal" anatomy and prepared for the "nontextbook" cases.
The anterior abdominal wall is divided into sections for descriptive purposes and to allow the physician to outline relationships of the viscera in the abdominal cavity. The center point of reference is the sternoxiphoid process, which is in the same plane as the 10th thoracic vertebra. The upper 2 sections are formed by the subcostal angle; the lower extends from the lower ribs to the crest of the ilium and forward to the anterior superior iliac spines. The base is formed by the inguinal ligaments and the symphysis pubica.
The viscera are located by dividing the anterolateral abdominal wall into regions. One line is placed from the level of each ninth costal cartilage to the iliac crests. Two other lines are drawn from the middle of the inguinal ligaments to the cartilage of the eighth rib. The 9 regions formed (Fig. 1–1) are the epigastric, umbilical, hypogastric, and right and left hypochondriac, lumbar, and ilioinguinal.
Within the right hypochondriac zone are the right lobe of the liver, the gallbladder at the anterior inferior angle, part of the right kidney deep within the region, and, occasionally, the right colic flexure.
The epigastric zone contains the left lobe of the liver and part of the right lobe, the stomach, the proximal duodenum, the pancreas, the suprarenal glands, and the upper poles of both kidneys (Fig. 1–2).
Abdominal viscera in situ. Inset shows projection of fetus in situ.
The left hypochondriac region marks the situation of the spleen, the fundus of the stomach, the apex of the liver, and the left colic flexure.
Within the right lumbar region are the ascending colon, coils of intestine, and, frequently, the inferior border of the lateral portion of the right kidney.
The central umbilical region contains the transverse colon, the stomach, the greater omentum, the small intestine, the second and third portions of the duodenum, the head of the pancreas, and parts of the medial aspects of the kidneys.
Located in the left lumbar region are the descending colon, the left kidney, and the small intestine. Within the limits of the right ilioinguinal region are ...