X-Ray Quiz – Discussion
The annotated image illustrates the salient features including antler sign and third mogul sign:
- Upper lobe vessels are prominent, indicating pulmonary venous hypertension. The named signs for prominent upper lobe vessels are: redistribution, antler sign, upturned mustache sign and cephalization.
- Right heart border three intercostal spaces and extends well into the right hemithorax, indicating right atrial enlargement. Normally right heart border is just outside the spinal column.
- Prominent left atrial appendage is seen on the left heart border. This is known as third mogul sign. First two moguls are aortic knuckle and main pulmonary artery.
- Elevation of left bronchus air column indicating left atrial enlargement. This causes a widening of the carinal angle .
A “third mogul” can also occur due to submitral aneurysms and post operative left ventricular pseudoaneurysm after mitral valve replacement .
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- Kumaresh A, Kumar M, Dev B, Gorantla R, Sai PV, Thanasekaraan V. Back to Basics – ‘Must Know’ Classical Signs in Thoracic Radiology. J Clin Imaging Sci. 2015 Jul 31;5:43.
- Aldridge S, Frazer J, Tawn J, Wilde P. Left ventricular aneurysm formation: an iatrogenic cause for the third mogul. Br J Radiol. 1988 Jun;61(726):463-8.