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Topic

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Right auricle of heart

The right auricle, also called the right atrial appendage (RAA), is a small, muscular, ear-shaped extension of the right atrium. It projects forward from the atrium, overlapping the ascending aorta, and serves as a reservoir that increases the capacity of the right atrium.

Its interior is lined by pectinate muscles, which are more prominent than those of the left auricle. The right auricle plays a functional role in augmenting right atrial volume during increased venous return and in modulating atrial contraction dynamics.

Clinically, the right auricle is less commonly involved in thrombus formation compared to the left auricle but can be significant in right atrial enlargement, arrhythmias, and congenital or acquired heart disease. It is an important landmark during cardiac surgery, device implantation, and catheter procedures.

Synonyms

  • Right atrial appendage (RAA)

  • Auricula dextra

  • Right auricle

Function

  • Acts as a reservoir that increases right atrial capacity during venous return

  • Contributes to atrial contraction and pressure regulation

  • Houses pectinate muscles that aid atrial mechanics

  • Serves as a landmark for surgical and interventional procedures

MRI Appearance

T1-weighted images:

  • Right auricle lumen appears as a signal void (black) due to blood flow

  • Thin auricular wall appears hypointense, separated from surrounding epicardial fat

T2 Cine (Cardiac-gated):

  • Provides dynamic assessment of auricular filling and contraction

  • Auricle seen as an outpouching of the right atrium with characteristic trabeculated wall

  • Cine imaging can detect abnormal motion, dilatation, or thrombus

T1 Post-Contrast (Gadolinium-enhanced):

  • Enhances as part of the right atrium, showing homogeneous bright lumen

  • Detects auricular thrombus as a non-enhancing filling defect

  • Useful in arrhythmia evaluation and atrial enlargement

MRI Non-Contrast Cardiac-Gated 3D Imaging:

  • Auricle visualized as a small, anteriorly projecting outpouching of the right atrium

  • Provides high-resolution anatomical mapping without contrast

  • Useful in congenital heart disease evaluation and surgical planning

CT Appearance

CT Coronary Angiography (CCTA):

  • Clearly shows the right auricle as a small anterior extension of the right atrium overlapping the ascending aorta

  • Opacifies brightly with intravenous contrast, allowing detection of thrombus, dilation, or structural anomalies

  • 3D reconstructions demonstrate its relationship to the ascending aorta, superior vena cava, and right coronary artery

  • Important for pre-surgical planning, arrhythmia evaluation, and atrial mapping

CT image

Right auricle of heart CT axial image -img-00000-00000

MRI image

Right auricle of heart mri image