The esophagus is a musculomembranous tube about 10 inches in length that
extends from the pharynx to the stomach (figure 3-1). It begins at the lower border of
the cricoid cartilage opposite the sixth cervical vertebra; descends in front of the
vertebral column; passes through the diaphragm at the level of the tenth thoracic
vertebra; and terminates at the cardiac orifice of the stomach opposite the eleventh
thoracic vertebra. The area where the esophagus traverses the diaphragm is called a
hiatus. A hiatal hernia is formed when any structure (usually a part of the stomach)
protrudes through the hiatus.
(1) The stomach is the most dilated part of the digestive tube, extending
between the end of the esophagus and the beginning of the small intestine (figures 3-2
and 3-4). It lies within the epigastric, umbilical, and left hypochondriac regions of the
abdomen (figure 1-7) with a small portion of the greater curvature extending into the left
lumbar region. The size, shape, and position of the stomach depend upon bodily
habitus (type) and vary with content and posture.
(2) There are two openings in the stomach. The upper opening at the
juncture of the esophagus is the cardiac orifice. The cardiac orifice is at the level of the
seventh left costal cartilage about 1 inch from the side of the sternum (the level of the
tenth thoracic vertebra). The lower opening that communicates with the duodenum is
the pyloric orifice. The pyloric orifice lies about 1 inch to the right of the midline at the
level of the upper border of the first lumbar vertebra (the level of the upper horizontal
line) (figure 2-22).
(3) The stomach has two borders, or curvatures. The lesser curvature
extends between the cardiac and pyloric orifices forming the concave border of the
stomach. The greater curvature forms the lower convex border of the stomach
(4) The stomach is divided into three parts: the upper part or fundus, the
middle part or body, and the lower part or pylorus. The fundus is the dome-shaped
portion lying directly beneath the dome of the diaphragm and above the cardiac orifice.
The fundus is marked off from the body by a plane of demarcation passing horizontally
through the cardiac orifice. The lower (smaller) end of the stomach, the pyloric portion,
is marked off from the body by a plane of demarcation passing through the angular
notch of the lesser curvature to the opposite dilation of the greater curvature.