Chapter 22: Abdomen
STRUCTURE AND FUNCTION OF THE ABDOMEN
● The abdomen is a large,oval cavity extending from the diaphragm down to the brim of
the pelvis. Four ayers of large,flat muscles form the ventral abdominal wall. These are
joined at the midline by a tendinous seam, the linea alba. One set, the rectus abdominis,
forms a strip extending the length of the midline, and its edge is often palpabl e
● Musculature: The ventral abdominal wall consists of four layers of flat muscles,
including the rectus abdominis, which is palpable and helps protect organs and flex the
spine
● Internal Anatomy
○ Peritoneum: A double-layered serous membrane
■ Parietal peritoneum lines the abdominal wall.
■ Visceral peritoneum covers the abdominal organs.
● Mesenteries: Double layers of peritoneum that:
○ Serve as pathways for blood vessels, nerves, and lymphatics.
○ Support and stabilize the abdominal organs (viscera).
● Greater Omentum: A fatty mesentery covering the ventral abdomen.
● Solid Viscera: maintains a constant shape
○ Include: liver, R kidney, ovaries, pancreas, spleen, adrenal glands,kidneys, uterus
(generally not palpable).
● Hollow Viscera: shape depends on content, usually not palpable, except when distended
colon (with feces) or bladder (with urine)
○ Include: stomach, gallbladder, small intestines (in all 4 quadrants, colon and
bladder).
● Spleen: soft lymphatic tissue, lies behind 9th and 10th ribs, lateral to the midaxillary line.
Normally not palpable
○ Filters out the blood, removes old blood cells, stores platelets and blood, plays a
crucial role in the immune system by housing white blood cells
● Aorta and Arterial pulsations: aorta is left of the midline in upper abdomen
○ Bifurcate into R and L common iliac arteries
● Pancreas: located behind the stomach
● Kidneys: bean-shaped, retroperitoneal
○ Protected by posterior ribs and musculature
○ Left kidney: lies at the 11th and 12th ribs
○ Right kidney: rests 1-2cm lower than the L due to liver position, may be palpable
● Adrenal glands: sit like caps on the upper poles of each kidney
○ Function as crucial endocrine glands
, ●
THE AGING ADULT AND THE GI SYSTEM
● Abdominal wall changes
○ Fat accumulation increases:
■ Women: suprapubic area due to estrogen.
■ Men: General abdominal area, worsened by a sedentary lifestyle.
○ Fat redistributes from the face/extremities abdomen/hips.
○ Abdominal muscles relax with age.
● GI system Changes
○ Functional ability is mostly maintained unless disease is present, but these
age-related changes occurs:
■ Decreased salivation, dry mouth and decreased taste.
■ Delayed Esophageal emptying increases aspiration risk if eating while
supine.
■ Decreased gastric acid secretion
● May cause:
○ pernicious anemia ( B12 absorption)
○ Iron-deficiency anemia
○ Calcium malabsorption
■ Increased Gallstones (more common in females
■ Decreased Liver Size & Function
● Leads to prolonged drug effects
● Increased fall/fracture risk with benzodiazepines.
CONSTIPATION IN OLDER ADULTS
● Affects more women
○ Often leads to daily laxative use
● Common causes of constipationL
STRUCTURE AND FUNCTION OF THE ABDOMEN
● The abdomen is a large,oval cavity extending from the diaphragm down to the brim of
the pelvis. Four ayers of large,flat muscles form the ventral abdominal wall. These are
joined at the midline by a tendinous seam, the linea alba. One set, the rectus abdominis,
forms a strip extending the length of the midline, and its edge is often palpabl e
● Musculature: The ventral abdominal wall consists of four layers of flat muscles,
including the rectus abdominis, which is palpable and helps protect organs and flex the
spine
● Internal Anatomy
○ Peritoneum: A double-layered serous membrane
■ Parietal peritoneum lines the abdominal wall.
■ Visceral peritoneum covers the abdominal organs.
● Mesenteries: Double layers of peritoneum that:
○ Serve as pathways for blood vessels, nerves, and lymphatics.
○ Support and stabilize the abdominal organs (viscera).
● Greater Omentum: A fatty mesentery covering the ventral abdomen.
● Solid Viscera: maintains a constant shape
○ Include: liver, R kidney, ovaries, pancreas, spleen, adrenal glands,kidneys, uterus
(generally not palpable).
● Hollow Viscera: shape depends on content, usually not palpable, except when distended
colon (with feces) or bladder (with urine)
○ Include: stomach, gallbladder, small intestines (in all 4 quadrants, colon and
bladder).
● Spleen: soft lymphatic tissue, lies behind 9th and 10th ribs, lateral to the midaxillary line.
Normally not palpable
○ Filters out the blood, removes old blood cells, stores platelets and blood, plays a
crucial role in the immune system by housing white blood cells
● Aorta and Arterial pulsations: aorta is left of the midline in upper abdomen
○ Bifurcate into R and L common iliac arteries
● Pancreas: located behind the stomach
● Kidneys: bean-shaped, retroperitoneal
○ Protected by posterior ribs and musculature
○ Left kidney: lies at the 11th and 12th ribs
○ Right kidney: rests 1-2cm lower than the L due to liver position, may be palpable
● Adrenal glands: sit like caps on the upper poles of each kidney
○ Function as crucial endocrine glands
, ●
THE AGING ADULT AND THE GI SYSTEM
● Abdominal wall changes
○ Fat accumulation increases:
■ Women: suprapubic area due to estrogen.
■ Men: General abdominal area, worsened by a sedentary lifestyle.
○ Fat redistributes from the face/extremities abdomen/hips.
○ Abdominal muscles relax with age.
● GI system Changes
○ Functional ability is mostly maintained unless disease is present, but these
age-related changes occurs:
■ Decreased salivation, dry mouth and decreased taste.
■ Delayed Esophageal emptying increases aspiration risk if eating while
supine.
■ Decreased gastric acid secretion
● May cause:
○ pernicious anemia ( B12 absorption)
○ Iron-deficiency anemia
○ Calcium malabsorption
■ Increased Gallstones (more common in females
■ Decreased Liver Size & Function
● Leads to prolonged drug effects
● Increased fall/fracture risk with benzodiazepines.
CONSTIPATION IN OLDER ADULTS
● Affects more women
○ Often leads to daily laxative use
● Common causes of constipationL
