From Echocardiography in ICU

Parasternal long axis view. The mitral valve is the valve farther from the probe. The posterior leaflet is attached to the posterior LV wall, the anterior leaflet is the closest from the aorta. In this view you can visualize the mitral valve, the coaptation of the leaflets and their relation to the mitral annulus, the chordae and papillary muscles. This is the best view to appreciate the dynamics of the mitral valve and to determine the mechanisms of regurgitation or stenosis.

Parasternal long axis view with color. In this view you can look for mitral regurgitation or indirect signs of mitral stenosis. However it is not the best view to assess mitral regurgitation severity since the regurgitant jet is almost perpendicular to the ultrasound beam. You will have to confirm in at least one more view. There is no regurgitation in this example.
Parasternal short axis view, level of the mitral valve. You can visualize the cross section of the mitral valve, which will look like a "fish mouth". The anterior leaflet is on the top, closer to the right ventricle. The posterior leaflet is at the bottom of the image.
Apical 4 chamber view. You can see the anterior (next to the aorta) and posterior (attached to the lateral wall) mitral leaflets. You can also visualize the mitral chordae and papillary muscles.
Apical 4 chamber view with color. You will use the color Doppler in this view to look for a mitral regurgitation, which will appear as a systolic blue jet from the left ventricle to the left atrium. In this view you can assess the severity of mitral regurgitation.There is no mitral regurgitation in this example.
Subcostal 4 chamber view. This is not the best view to assess the mitral valve, but if other imaging windows are not available in the patient, subcostal 4 chamber view can help you to rule out significant mitral regurgitation.