ANATOMY
Abdomen
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Abdomen Wall
The abdominal musculature has three distinct layers that take
three different directions. The external oblique muscle, internal oblique
muscle, and transverse abdominis muscle may be sequentially split and retracted
so that extensive -?-suturing
is unnecessary to provide a strong repair (McBurney's incision).
Because the
-?-Linea alba
is relatively avascular, incisions may not heal well and predispose to
epigastric herniation.
Above the arcuate line, the anterior leaf of the rectus
sheath is formed by fusion of the external oblique and internal oblique
-?-Aponeuroses; the posterior leaf
is formed by the fusion of the internal oblique and transverse abdominis
-?-Aponeuroses.
Below the arcuate line, the anterior leaf of the rectus
sheath is formed by fusion of all
-?-Three
aponeuroses and there is
-?-No
posterior leaf.
The inferior epigastric artery passes into the rectus sheath
at the arcuate line. This is a potential site for
-?-spigelian
herniation into the rectus sheath.
| Hernia | Pathway |
|---|---|
| -?-Direct Inguinal | Through the inguinal triangle bounded by inguinal ligament, inferior epigastric artery, and rectus abdominis-therefore, medial to the inferior epigastric artery. Exits through the superficial inguinal ring adjacent to the spermatic cord.Usually acquired |
| -?-Indirect Inguinal | Through the deep inguinal ring and along the inguinal canal-therefore, lateral to the inferior epigastric artery. Exits through the superficial ring within the spermatic cord. Usually congenital |
| -?-Femoral | Passes inferior to the inguinal ligament through the femoral ring into the thigh. More prevalent in women |
GI Tract
Peptic ulceration of the lower esophagus, stomach, or
superior duodenum is referred along the greater
-?-splanchnic
nerve to the fifth and sixth dermatomes which include the epigastric region.
The hepatic triangle, bounded by the cystic duct,
gallbladder, and common hepatic duct, contains the cystic arteries, and right
-?-hepatic
artery with potential for extensive variation.
The duodenal papilla usually contains the hepatopancreatic
ampulla, formed by the joining of the common bile duct and the pancreatic duct.
If blocked by a stone,
-?-pancreatitis
may develop.
The tail of the pancreas contains the majority of the
pancreatic islets (of Langerhans), a consideration in pancreatic
-?-resection.
Ileal (Meckel's) diverticulum is found in about
-?-3 percent
of the population, located within 3 feet of the ileocecal junction (on the
antimesenteric side of the ileum), and usually less than 3 inches long. Peptic
ulceration of adjacent ileal mucosa and volvulus are complications.
The hepatic portal vein directs venous return from the
gastrointestinal tract to the
-?-liver.
Because the hepatic portal system has no valves, blood need
not flow toward the liver. Liver disease (such as
-?-Cirrhosis) or compression of a
vein (as in pregnancy or
-?-Constipation) results in blood
shunting through the anastomotic connections to the systemic venous system.
| Location | Anastomotic Connections | Signs & Symptoms |
|---|---|---|
| Esophagus | Azygos veins with left gastric and short gastric veins | -?-Esophageal varices, intractable hematemesis |
| Umbilicus | Paraumbilical veins with superior and inferior epigastric veins | -?-Caput medusa |
| Rectum | Superior rectal vein with middle and inferior rectal veins | -?-Internal and external hemorrhoids |
Kidneys, Ureters, Adrenal Glands
The renal fascia (the false capsule or Gerota's fascia) is a
discrete fascial layer that surrounds each kidney. Paranephric fat outside this
capsule and perinephric fat inside this fascial layer support the
-?-Kidney.
Minor calyces receive one or two pyramids before fusing
into major calyces. Two to four minor calyces join to form major calyces that
coalesce to form the
-?-Renal
pelvis.
The ureters narrow at three points-at the renal pelvis, at
the pelvin brim, and the
-?-Bladder. Kidney stones may lodge
at these locations with pain referred respectively to the
-?-Subcostal, inguinal, and perineal
regions.
Adrenal arteries arise from the inferior phrenic
arteries, the aorta, and the renal arteries. The right adrenal vein usually
drains -?-Medially
into the inferior vena cava; the left adrenal vein usually drains
-?-Inferiorly
into the left renal vein.
The superior lumbar trigone (a posterior approach to the
kidneys, suprarenal glands, and the upper ureters) is bounded by the quadratus
lumborum muscle, superior border of the internal oblique muscle, and the
-?-Twelfth
rib.
| Organ | Referral area | Pathway |
|---|---|---|
| Diaphragm Central Marginal |
C3-C5: Neck and shoulder T5-T10: Thorax |
-?-
Phrenic nerve Intercostal nerves |
| Stomach, gallbladder, liver, bile duct, superior duodenum |
-?-T5-T9:
Lower thorax Epigastric region |
Celiac plexus to greater splanchnic nerve |
| Inferior duodenum, jejunum, ileum, appendix, ascending colon, transverse colon | T10-T11: Umbilical region | -?-Superior mesenteric plexus to lesser splanchnic nerve |
| Organ | Referral area | Pathway |
|---|---|---|
| Kidneys, upper ureters, gonads | T12-L1: Lumbar and ipsilateral inguinal regions | -?-Aorticorenal plexus to lumbar splanchnic nerves |
| Descending colon, sigmoid colon, mid ureters | L1-L2: Pubic andinguinal regions, anterior scrotum or labia, anterior thigh | -?-Aortic plexus to lumbar splanchnic nerves |