Sectional Anatomy

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Sectional Anatomy

• GI

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Technique

• Use a 3.5 -5.0 transducer
• Patient should fast at least 4 hours prior to
  exam to ensure distension of the GB and to
  minimize the stomach gas
• To further evaluate the the stomach and duodenum
  the patient can drink 10-40 oz of water through a
  straw to improve visualization
• To evaluate the colon a water enema can be given
  and transrectal ultrasound used

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GI Exam

• There are not many uses for ultrasound in the
  evaluation of the GI system. Two uses for
  ultrasound are
• Ultrasound is the examination of choice for
  pyloric stenosis evaluation in the pediatric
  patient
• Ultrasound can be used to evaluate for
  appendicitis in patients

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Gastrointestinal Tract

• Begins at the gastroesophageal junction and ends
  at the rectum
• Consists of the esophagus, stomach and large bowel

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GI Track
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Esophagus

• Hollow muscular tube that extends from the
  pharynx to the gastroesophageal junction, which
  is where the esophagus enters into the stomach
• By ultrasound you can visualize the esophagus in
  the neck when scanning the thyroid, it appears as
  a tubular structure with distal shadowing due to
  the air in the esophagus

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Esophagus
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Esophagus
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Esophagus

• The gastroesophageal junction can be seen in a
  sagittal view just to the left of the midline
  between the left lobe of the liver and the aorta

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Gastroesophageal Junction
?
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GI
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Parts of the Stomach

• Cardia - surrounds the lower esophageal sphincter
• Fundus - rounded portion superior and to the left
  of
• the cardia
• Body - large central portion below fundus
• Lesser curvature
• Greater curvature

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Parts of the Stomach

• Pylorus - distal aspect of stomach
• The pylorus is evaluated in infants if they are
  suspected of having pyloric stenosis
• Function is to store food before it goes to the
  duodenum
• Sonographicly appears target or bulls eye
  lying anterior to the aorta

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Pylorus
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Pylorus
?
?
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Pylorus
?
?
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Stomach
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Small Bowel

• Duodenum - originates at pyloric sphincter and
• merges with jejunum
• Jejunum - extends from the small bowel to the
  ileum
• Ileum - longest portion of small bowel and joins
  to
• the large intestine
• Receives food from the stomach and breaks it down
  further by digestion, also absorption of
  nutrients
• When fluid filled it appears as a tubular
  structure in sagittal and as a target structure
  in transverse

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GI Track
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Duodenum
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Small Large Bowel
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Small Large Bowel
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Large Bowel Appendix

• 1.5 meters long from ileum to anus
• Cecum - blind pouch of bowel
• Appendix - tubular structure attached to the
• cecum
• Ascending colon - ascends on the right side of
• the abdomen
• Transverse colon - crosses the abdomen
• Descending colon - descends on the left side of
• the abdomen

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GI Track
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Bowel
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Transverse Colon
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Ascending Colon
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Large Bowel Appendix

• Sigmoid colon - begins at the iliac crest and
• terminates as the
  rectum
• Rectum - last 20 cm of the colon ending in the
  anal
• canal
• Function is the absorption of water, minerals and
  vitamins that will pass to the liver also for the
  formation and expulsion of feces
• When seen it will appear similar to the small
  bowel

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GI Track
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Appendix
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Appendix
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Rectum
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GI Wall

• All of the GI walls are measured from the
  innermost echogenic layer to outermost echogenic
  layer
• The GI wall has
• Muscularis interna (Submucosa)- echogenic inner
  layer
• Muscularis externa - hypoechoic outer rim of
  muscle
• Serosa - outermost covering layer - echogenic

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Wall Size

• Stomach - found directly under the diaphragm in
  the
• epigastric region, wall
  measures 3-5 mm
• Small bowel - found in the central and lower
  parts of
• the abdominal cavity, wall measures
  lt to 3 mm
• Appendix - RLQ, wall measures lt2mm
• Large bowel - found along the outer abdominal
  walls
• on the Rt/Lt, wall lt5mm

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Anomalies of the GI Tract

• These anomalies can be seen by ultrasound
• Appendicitis
• Diverticulitis
• Hypertrophic pyloric stenosis (HPS)
• Crohns Disease
• Obstruction