Right Atrium

Size

Dilated if bigger than LA
A4C - Measure minor (width) and major (length) axis. Planimetry RA.

RA1

RAP

Assume it is 10 or
Measure IVC in inspiration and expiration.

RA2

Obviously measuring it directly via a CVC is more accurate.

Normal structures which may be seen in RA
Eustachian valve - thin flap at junction of IVC and RA. Size and mobility variable.
Coronary sinus.
Chiari network - web across RA in 2% population. Of no significance.