Page 417 - Fundamentals of anatomy physiology
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404 Unit 2 Support and Movement
Clinical Note caused by unusually high abdominal pressures. Injuries to the
abdomen or inherited weakness or distensibility of the canal
Hernia When the abdominal muscles contract forcefully, can have the same effect.
pressure in the abdominopelvic cavity can increase dramati-
cally. That pressure is applied to internal organs. If the individ- The esophagus and major blood vessels pass through
ual exhales at the same time, the pressure is relieved because openings in the diaphragm, the muscle that separates the
the diaphragm can move upward as the lungs collapse. But thoracic and abdominopelvic cavities. In a diaphragmatic
during vigorous isometric exercises or when lifting a weight hernia abdominal organs slide into the thoracic cavity. If entry
while holding one’s breath, pressure in the abdominopelvic is through the esophageal hiatus, the passageway used by the
cavity can rise to 106 kg/cm2, roughly 100 times the normal esophagus, a hiatal hernia (hı.-A. -tal; hiatus, a gap or opening)
exists. The severity of the condition depends on the location
11 pressure. A pressure that high can cause a variety of problems, and size of the herniated organ or organs. Hiatal hernias are
including hernias. A hernia develops when a visceral organ or very common. Most go unnoticed, although they may in-
part of an organ protrudes abnormally through an opening crease the severity of gastric acid entry into the esophagus.
in a surrounding muscular wall or partition. There are many (This condition is gastroesophageal reflux disease, or GERD,
types of hernia. Here we will consider only inguinal (groin) commonly known as heartburn.) Radiologists see hiatal her-
hernias and diaphragmatic hernias. nias in about 30 percent of individuals whose upper gastroin-
Late in the development of male fetuses, the testes de- testinal tracts are examined with barium-contrast techniques.
scend into the scrotum. They pass through the abdominal wall
at the inguinal canals. In adult males, the sperm ducts and Sometimes clinical complications other than GERD de-
associated blood vessels penetrate the abdominal muscula- velop. They generally do so because abdominal organs that
ture at the inguinal canals as the spermatic cords, on their way have pushed into the thoracic cavity are exerting pressure
to the abdominal reproductive organs. In an inguinal hernia, on structures or organs there. Like inguinal hernias, a dia-
the inguinal canal enlarges. The abdominal contents, such as phragmatic hernia can result from congenital factors or from
a portion of the greater omentum, small intestine, or (more an injury that weakens or tears the diaphragm. If abdominal
rarely) urinary bladder, enter the inguinal canal. If these struc- organs occupy the thoracic cavity during fetal development,
tures become trapped or twisted, surgery may be required to the lungs may be poorly developed at birth.
prevent serious complications. Inguinal hernias are not always
External Inguinal Inguinal
abdominal canal hernia
oblique Herniated
intestine
External
inguinal
ring
Spermatic
cord
