Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed
The thymus is normally prominent in the newborn and increases in size during the first few months of life. The appearance of the thymus may resemble a sail ("sail sign"). The thymic margin may have a wavy appearance ("thymic wave") due to indentations caused by the anterior costal impressions on the soft thymus. A prominent thymus implies a healthy infant, while stressful situations (infection, etc.) lead to thymic atrophy. The thymus decreases in size by 1-3 years old. By 4 years of age it can only be seen on a CXR in 2% of patients, but it is usually seen on CT of the chest in patients less than 20 years old. The thymus changes in size and shape during inspiration and expiration with a relative increase in transverse thymic diameter during expiration that returns to normal with inspiration.
See References Chapter.
Section Top | Title Page
Follow us on Twitter @pedseducation and @pedsimaging
Please send us comments by filling out our Comment Form.
All contents copyright © 1992-2016 Donna M. D'Alessandro, M.D. and Michael P. D'Alessandro, M.D. and the authors. All rights reserved.
"Virtual Pediatric Hospital", the Virtual Pediatric Hospital logo, and "A digital library of pediatric information" are all Trademarks of Donna M. D'Alessandro, M.D. and Michael P. D'Alessandro, M.D.
Virtual Pediatric Hospital is funded in whole by Donna M. D'Alessandro, M.D. and Michael P. D'Alessandro, M.D. Advertising is not accepted.
Your personal information remains confidential and is not sold, leased, or given to any third party be they reliable or not.
The information contained in Virtual Pediatric Hospital is not a substitute for the medical care and advice of your physician. There may be variations in treatment that your physician may recommend based on individual facts and circumstances.