Appendix Anatomy and Clinical Significance

Imaging Identification

The American College of Radiology recommends that a normal appendix diameter should be less than 6 mm when compressed 1
The American College of Radiology states that CT imaging can visualize the appendix as a tubular structure arising from the cecum, with wall thickness normally less than 3 mm 1
The American College of Radiology notes that MRI can identify the appendix with high sensitivity, especially in pregnant patients where the appendix visualization rate reaches 80% compared to only 7% with ultrasound 2
The American College of Radiology identifies the T1 bright appendix sign as a specific sign for a normal appendix on MRI, characterized by a high-intensity signal filling more than half the length of the appendix on T1-weighted imaging 3

The World Society of Emergency Surgery provides a weak recommendation supporting appendix removal when it appears normal during surgery for suspected appendicitis in symptomatic patients, due to the limitations of visual assessment during surgery 4

The World Journal of Emergency Surgery strongly recommends routine histopathology after appendectomy to identify unexpected findings, as operative findings and intra-operative grading correlate better than histopathology with morbidity and overall outcomes 5
The World Journal of Emergency Surgery notes that the decision to remove a normal-appearing appendix should weigh the risk of leaving a potentially abnormal appendix against the risk of appendectomy 5