Applied Anatomy of Abdomen

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Applied Anatomy of Abdomen

• Abdomen, Pelvis Perineum Unit Lecture 10
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Lecture 1 Anterior Abdominal wall

• Surgical Incisions
• Along lines of cleavage?
• Location depends on type of operation, location
  of organ(s), bony or cartilaginous boundaries,
  avoidance of (especially motor) nerves,
  maintenance of blood supply, and minimizing
  injury to muscles fascia.
• A. Longitudinal Incisions
• 1. Median or midline incision through linea alba
  above/below umbilicus
• 2. Paramedian incisions longitudinal incisions
  para-sagittal plane.
• 3. Pararectus incisions along lateral border of
  rectus sheath. undesirable?
• 4. Abdominothoracic incision for lower end of
  esophagus.
• B. Oblique and Transverse Incisions
• 1. Gridiron (muscle-splitting) incisions used for
  an appendectomy. McBurney incision is made at
  McBurney point? less popular?
• 2. Suprapubic (Pfannenstiel) incisions (bikini
  incisions) at pubic hairline for cesarean section
  and most gynecological and obstetrical
  operations.
• 3. Subcostal incisions for gallbladder biliary
  ducts (right side) and for spleen (left side). It
  is parallel inferior to costal margin?
• 4. Inguinal incisions for repairing hernias may
  injure ilioinguinal nerve.

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Lecture 1 Anterior Abdominal wall

• Paracentesis of the Abdomen
• It is withdrawal of excessive collections of
  peritoneal fluid, as in ascites. A needle or
  catheter is inserted through anterior abdominal
  wall. If a needle is inserted in the flank, it
  will pass through the following
• skin,
• superficial fascia,
• deep fascia,
• aponeurosis of external oblique,
• internal oblique muscle,
• transversus abdominis muscle,
• fascia transversalis,
• extraperitoneal fatty tissue
• parietal peritoneum.

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Lecture 1 Anterior Abdominal wall

• Collateral Pathways of Superficial Abdominal
  Veins
• When flow in inferior vena cava is
• obstructed, anastomoses between
• tributaries of superior inferior vena
• cavae , such as thoracoepigastric vein,
• may provide collateral pathways by which
• obstruction may be bypassed, allowing
• blood to return to the heart. Small
• cutaneous (systemic) veins surrounding
• umbilicus also anastomose with the
• paraumbilical veins (tributaries of
• portal vein), which run with obliterated
• umbilical vein (round ligament of liver).
• During either caval or portal obstruction,
• anastomosing veins may also become
• distended, causing caput medusae
• appearance.

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Lecture 2 Inguinal Canal Scrotum

• Varicocele
• A varicocele is a condition in which the veins of
  the pampiniform plexus are elongated and dilated.
  It is a common disorder in adolescents and young
  adults, with most occurring on the left side.
  This is thought to be because the right
  testicular vein joins the low-pressure inferior
  vena cava, whereas the left vein joins the left
  renal vein, in which the venous pressure is
  higher.

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Lecture 3 Posterior Abdominal Wall

• Psoas Abscess and Tuberculosis
• Psoas fascia covers anterior surface of psoas
  muscle and can influence direction taken by a
  tuberculous abscess. TB of thoracolumbar
  vertebrae results in destruction of vertebral
  bodies, with possible extension of pus laterally
  under psoas fascia. From there, pus tracks
  downward, following course of psoas muscle, and
  appears as a swelling in upper part of thigh
  below inguinal ligament. It may be mistaken for a
  femoral hernia.

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Lecture 5 Esophagus, Stomach Duodenum

• Hiatus Hernia
• A hiatus hernia is a protrusion of a part of
  stomach into mediastinum through esophageal
  hiatus of diaphragm. Hernias occur most often in
  people after middle age, possibly because of
  weakening of muscular part of diaphragm and
  widening of esophageal hiatus. Two types are
• Paraesophageal hiatal hernia less common, cardia
  remains in its normal position. However, a part
  of fundus extends through esophageal hiatus
  anterior to the esophagus.
• Sliding hiatal hernia abdominal part of
  esophagus, cardia, and parts of fundus of stomach
  slide superiorly through esophageal hiatus to
  thorax.

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Lecture 5 Esophagus, Stomach Duodenum

• Vagotomy
• It is surgical section of the vagus nerves
  because secretion of acid is largely controlled
  by vagus nerves.
• A. Truncal vagotomy (surgical section of vagal
  trunks) is rarely performed because innervation
  of other abdominal structures is also sacrificed.
  
• B. Selective gastric vagotomystomach is
  denervated but vagal branches to pylorus, liver
  biliary ducts, intestines celiac plexus are
  preserved.
• C. Highly selective vagotomy attempts to
  denervate only area in which parietal cells are
  located, sparing other gastric function
  (motility) stimulated by vagus nerve.

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Lecture 6 Small Large Intestine

• Visceral Referred Pain There are two types of
  pain
• A. Somatic pain (sharp and localized easily)
  arises from organs such as muscles, bones
  parietal peritoneum.
• B. Visceral pain (dull and poorly localized)
  arises from an organ such as stomach and
  intestine.
• C. Referred pain (dull and localized) is a
  visceral pain arising from viscera but felt
  (radiate) to dermatome level, which receives
  visceral fibers from organ concerned.

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Lecture 6 Small Large Intestine

• Appendicitis
• Is acute inflammation of the appendix is caused
  by occlusion of lumen either in young people by
  hyperplasia of lymphatic follicles in appendix Or
  in older people, obstruction results from
• a fecolith that forms around a center of fecal
• matter. When secretions from appendix
• cannot escape, appendix swells, stretching
• visceral peritoneum. Visceral pain of
• appendicitis, therefore, referred to
• periumbilical region because afferent
• pain fibers enter spinal cord at T10 level.
• Later, severe pain in right lower quadrant
• results from irritation of parietal
• peritoneum lining abdominal wall
• (Shifting Pain).

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Lecture 8 Liver, Spleen and Pancreas

• Gallstones
• A gallstone is a concretion composed chiefly of
  cholesterol crystals in biliary system. They may
  cause injury to gallbladder or obstruction of
  biliary tract. Distal end of hepatopancreatic
  ampulla is narrowest part of biliary passages and
  is a common site for
• impaction of gallstones. Hartmann pouch
• (infundibulum of gallbladder) is a dilation at
• junction of neck of gallbladder and cystic duct
• and is another common site for impaction.
• Gallstones lodged in cystic duct causes
• biliary colic (intense, spasmodic pain). If stone
  
• blocks cystic duct, cholecystitis (inflammation
  of
• gallbladder) occurs because of bile accumulation
• enlargement of gallbladder.
• Acute Cholecystitis is inflammation of
• gallbladder which may cause irritation of
• subdiaphragmatic parietal peritoneum,
• which is supplied in part by phrenic nerve. This
• may give rise to referred pain over right
  shoulder.

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Lecture 8 Liver, Spleen and Pancreas

• Gallstones in the Duodenum
• Dilated and inflamed gall bladder owing to an
  impacted gallstone in its duct, may develop
  adhesions with adjacent viscera. Continued
  inflammation may break down (ulcerate) tissue
  boundaries between gallbladder and a part of
  alimentary tract adherent to it, resulting in a
  cholecystenteric fistula.
• Because of their proximity to
• gallbladder, the superior part of
• duodenum and transverse colon
• are most likely to develop a
• fistula of this type. The fistula
• would enable a large gallstone,
• incapable of passing though the
• cystic duct, to enter the
• alimentary tract that may become
• trapped at the ileocecal valve,
• producing a bowel obstruction
• (gallstone ileus).

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Lecture 8 Liver, Spleen and Pancreas

• Pancreatic Head Cancer
• Cancer of the head often compresses and obstructs
  the bile duct and/or the hepatopancreatic
  ampulla. This condition causes obstruction,
  resulting in the retention of bile pigments,
  enlargement of the gallbladder, and jaundice
  (obstructive jaundice). Cancer of the neck and
  body of the pancreas may cause portal or inferior
  vena caval obstruction because the pancreas
  overlies these large veins.

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Lecture 9 Kidney Ureter

• Renal and Ureteric Calculi
• Calculi may form and become located in calices of
  kidneys, ureters, or urinary bladder. A renal
  calculus (kidney stone) may pass from kidney into
  renal pelvis and then into ureter. If stone is
  sharp, or it is larger than normal lumen of
  ureter (about 3 mm) causing excessive distension
  of this muscular tube, ureteric calculus will
  cause severe intermittent pain (ureteric colic)
  as it is gradually forced down the ureter by
  waves of contraction. Calculus may cause complete
  or intermittent obstruction of urinary flow.
  Depending on level of obstruction, pain may be
  referred to the lumbar or inguinal regions, or
  the external genitalia and/or testis.

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Lecture 9 Kidney Ureter

• Pelvic Kidney (ectopic kidney)
• Kidney may be arrested in some part of its normal
  embryonic ascent it usually is found at the brim
  of pelvis.
• Horseshoe Kidney
• Caudal ends of both kidneys fuse as they develop
  resulting in horseshoe kidney. Both kidneys start
  to ascend from pelvis, but the interconnecting
  bridge becomes trapped behind inferior mesenteric
  artery, so kidneys come to rest in low lumbar
  region. Both ureters are kinked as they pass
  inferiorly over the bridge of renal tissue,
  producing urinary stasis, which may result in
  infection and stone formation.

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