The celiac trunk originates from the aorta at the upper border of the LI vertebra.
The superior mesenteric artery originates at the lower border of the LI vertebra.
The renal arteries originate at approximately the LII vertebra.
The inferior mesenteric artery originates at the LIII vertebra.
The aorta bifurcates into the right and left common iliac arteries at the level of the LIV vertebra.
The left and right common iliac veins join to form the inferior vena cava at the LV vertebral level.
Using abdominal quadrants to locate
The abdomen can be divided into quadrants by a vertical median plane and a horizontal transumbilical plane, which passes through the umbilicus (Fig. 4.181):
The liver and gallbladder are in the right upper quadrant.
The stomach and spleen are in the left upper quadrant.
The cecum and appendix are in the right lower quadrant.
The end of the descending colon and sigmoid colon are in the left lower quadrant.
Most of the liver is under the right dome of the diaphragm and is deep to the lower thoracic wall. The inferior margin of the liver can be palpated descending below the right costal margin when a patient is asked to inhale deeply. On deep inspiration, the edge of the liver can be felt “slipping” under the palpating fingers placed under the costal margin.
A common surface projection of the appendix is
McBurney’s point, which is one-third of the way up along a line from the right anterior superior iliac spine to the umbilicus.
Defining surface regions to which pain from the gut is referred
The abdomen can be divided into nine regions by a midclavicular sagittal plane on each side and by the subcostal and intertubercular planes, which pass through the body transversely (Fig. 4.182). These planes separate the abdomen into: three central regions (epigastric, umbilical, pubic), and three regions on each side (hypochondrium, flank, groin).
Pain from the abdominal part of the foregut is referred to the epigastric region, pain from the midgut is referred to the umbilical region, and pain from the hindgut is referred to the pubic region.
Where to find the kidneys
The kidneys project onto the back on either side of the midline and are related to the lower ribs (Fig. 4.183):
The left kidney is a little higher than the right and reaches as high as rib XI.
The superior pole of the right kidney reaches only as high as rib XII.
The lower poles of the kidneys occur around the level of the disc between the LIII and LIV vertebrae. The hila of the kidneys and the beginnings of the ureters are at approximately the LI vertebra.
The ureters descend vertically anterior to the tips of the transverse processes of the lower lumbar vertebrae and enter the pelvis.
Where to find the spleen
The spleen projects onto the left side and back in the area of ribs IX to XI (Fig. 4.184). The spleen follows the contour of rib X and extends from the superior pole of the left kidney to just posterior to the midaxillary line.
Fig. 4.1 Abdomen. A. Boundaries.
B. Arrangement of abdominal contents. Inferior view.
Fig. 4.2 The abdomen contains and protects the abdominal viscera.
Fig. 4.3 The abdomen assists in breathing.
InspirationExpirationDiaphragmRelaxation of diaphragmContraction ofdiaphragmContraction of abdominal musclesRelaxation ofabdominalmuscles
Fig. 4.4 Increasing intraabdominal pressure to assist in micturition, defecation, and childbirth.
Laryngeal cavity closedAir retained in thoraxFixed diaphragmContraction of abdominal wallIncrease inintraabdominalpressureMicturitionChild birthDefecation