Parasternal Long Axis View
The fourth view in the series is the parasternal long axis view. Place your echo probe somewhere near the lower left sternal edge, around the fourth intercostal space. The side marker on the probe should now be pointing toward the patient's right shoulder.
This view is slightly less anatomically tangible than the apical four chamber view, so take a second to get your head around it. Remember that the long axis of the heart lies at an angle within the chest, and what you're trying to do with this view is image along the long axis of the heart, as if you were cutting it lengthwise with a knife.
By convention the apex of the heart is seen towards the left of the screen, the base of the heart to the right.
A standard image should allow you to clearly see normal motion of the mitral and aortic valve leaflets:
(AV-Aortic Valve, IVS-Inter-ventricular septum, LA-Left Atrium, LV-Left Ventricle, MV-Mitral Valve, RV-Right Ventricle)
If you're in any doubt about the valve motion, as with any view, use the high resolution zoom feature to focus on the area of interest:
The long axis view is another important view to look for a VSD. Especially a membranous VSD sitting just below the aortic valve. Place the colour Doppler window across the septum, and then sweep to the left and to the right to visualise the whole of the septum:
As ever, remember that ultrasound produces only a 2D image of what is a 3D structure. Using sweeps from side to side ensure that all of the heart is interrogated.
As part of the sweep you will tilt to look up towards the patient's left shoulder, allowing you to visualise the pulmonary valve:
The valve leaflets should virtually disappear during systole as they are so thin. Any thickening of the leaflets suggests valvar stenosis. Use colour Doppler to interrogate flow across the valve:
(LV-Left Ventricle, MPA-Main Pulmonary Artery, PV-Pulmonary Valve, RV-Right Ventricle)
You will also tilt down towards the left hip, allowing you to visualise the tricuspid valve: