• Probe: Linear
  • Mode: Peds Abdomen
  • Starting Depth: 4 cm


  • Psoas muscle
  • Iliac vessels
  • Appendix
    • Long axis with blind sac connected to cecum
    • Short axis with target sign


  • Start at point of maximal tenderness
  • If appendix not identified, use anatomy to orient and localize ileoceal junction
  • Trace cecum to appendix
  • Use graded compression to eliminate gas artifact and assess appendix compressibility

Abnormal measurement

  • Diameter > 6 mm

Appendix in long axis

Blind ended tubular structure, usually < 6cm in diameter, compressible


Appendix is > 6 mm, non-compressible 

Fat Stranding, Fecalith

Secondary signs suggestive of appendicitis 

Free Fluid

Appendix obscured by bowel gas
Fix → Move bowel gas out of view using graded compression, or reposition patient

Thickened ileum is mistaken for appendix
Fix → Identify blind ended tip and trace back to cecum

Distal tip appendicitis is overlooked
Fix → Visualize entire length of appendix to the blind end of the tip

False positive interpretation
Fix → A normal appendix can be > 6mm. For a positive finding, there must be an enlarged, non-compressible appendix + signs of inflammation on ultrasound or lab work, and pain