Tag Archives: Heart

PLAX view: Orientation

The parasternal long axis view or the PLAX is obtained by placing the transducer to the left of the sternum in 3rd or 4th intercostal space with the orientation marker toward patient’s right shoulder or 10 o’ clock position, which is essentially the ‘long axis’ of the heart. For better understanding of the procedure, watch my video 3 (~19:33) and video 8 (~5:22).

The following figures demonstrate the plane in which we are slicing the heart to obtain PLAX view.

PLAX plane
Orientation to the PLAX view in lying down position

Normal sonographic anatomy of the PLAX view:

In a technically ‘good’ PLAX view, both the mitral valve and the aortic valve will be clearly seen and will be roughly in the center of the image, stacked on top of each other. The base of the left ventricle (LV), but not the apex, will be visible. The right ventricular outflow tract (RVOT) will be seen on the top of the image. Note that the right ventricle has noticeably thinner and smaller walls compared to the LV. The right atrium (RA) is not visible in this view. On the right, the left atrium (LA), aorta and RVOT each should roughly take up one-third of the image. Pericardium appears as a bright border and the descending thoracic aorta is visible at the bottom of the image, as a circle outside the LA.

Focus on FoCUS: The 4 basic views of the heart

FoCUS = Focused Cardiac Ultrasound

FoCUS consists of 4 basic views of the heart namely parasternal long- and short-axis views, the apical 4-chamber view, and the subxiphoid view, as described in the Rapid Ultrasound in Shock (RUSH) protocol.

The parasternal views are obtained with the probe positioned just left of the sternum at intercostal space 3 or 4. It’s like slicing the heart in ‘its’ sagittal and transverse planes respectively.

The long axis of the heart is oblique to that of the body, extending from right shoulder to the left hip

The apical 4-chamber view of the heart is obtained by placing the probe just below the nipple line at the point of maximal impulse of the heart. It’s like slicing the heart in its coronal plane.

The subxiphoid 4-chamber view is obtained with the probe aimed up toward the left shoulder from a position just below the subxiphoid tip of the sternum. The image is similar to that of Apical 4C except that it is slightly tilted to the right. It is easier to obtain than the apical 4C and helps to assess pericardial effusion quickly. Note that you’ll see the liver on top of the image as we are using it as a window to look at the heart.

It is important to have an idea of all these 4 views of the heart, as some views may not be well visualized depending on the individual patient’s body habitus and position, necessitating an alternative approach.