Welcome to the ehealthforum and I am really glad to help you out.
A prominent aortic knob can occur due to a slight rotation of the patient while taking the x-ray film and if there was no rotation, then there a few possibilities which need to be looked into.
The aortic knob is a radiographic structure that is formed by a part of the aortic arch and a portion of the descending aorta.
In normal people the aortic knob measures less than 35mm when measured from the lateral border of the trachea to the lateral border of the aortic knob.
If the knob is greater than 35 mm, then it could be due to increased pressure, flow, or changes in the elasticity of the wall e.g. cystic medial necrosis (damage to the wall of the aorta) ,dissection of the aorta (in this also thereâs a tear in the wall of the aorta â this is a very serious disease and if not urgently attended to can be catastrophic.
However, the possibility seems less likely in your case).
To confirm these possibilities, either a CT scan or an MRI needs to be done.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided.
For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.
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