There are many types of segmentation of the left ventricular wall, such as the 9-point, 16-point, and 20-point methods. The current method is the 16-point method, which is recognized and recommended by the American Society of Ultrasonography, while the 9-point and 20-point methods are rarely used because they are too coarse and cumbersome.
The 16-point method uses three long-axis views of the left ventricle (LV long-axis view, apical 4-chamber view, and apical 2-chamber view) and three short-axis views (LV short-axis mitral level, papillary muscle level, and apical level). The left ventricular long-axis view shows: anterior-basal septum, anterior-middle septum, posterior-basal wall, and posterior-middle wall; the apical 4-chamber view shows: anterior-basal septum, middle septum, and apical septum, and lateral-basal wall, lateral-middle wall, and lateral-apical wall; the apical 2-chamber view shows: inferior-basal wall, inferior-middle wall, and inferior-apical wall, and anterior-basal wall, anterior-middle wall, and anterior-apical wall; and the left ventricular short-axis view at the mitral orifice level shows: anterior-basal septum, inferior-basal septum, inferior-basal wall, posterior-basal wall, and lateral-basal wall. The LV short-axis view at the level of the mitral orifice shows: anterior septum, posterior septum, posterior subapical wall, lateral subapical wall, and anterior subapical wall; the papillary muscle level view shows: anterior mid septum, mid septum, inferior mid wall, posterior mid wall, lateral mid wall, and anterior mid wall; the apical level view shows: apical septum, inferior apical wall, lateral apical wall, and anterior apical wall. And any of the 16 segments can be shown in two different views. The long axis and short axis overlap and complement each other. Zhang Hongchao, Department of Cardiovascular Surgery, Air Force General Hospital
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http://hi.baidu.com/tongxuzhongyiyuan/blog/item/ec6220678f7ba9fcf73654b7.html
The American Society of Echocardiography divided the left ventricle into 16 segments. These views complement each other and play a crucial role in the diagnosis of segmental ventricular wall motion abnormalities by echocardiography.
Now, in the new 17-segment segmentation method based on the original 16 segments, the apical cap portion is added as 1 segment, which means that the apical portion of the single surviving heart is one segment.
For beginners, they may memorize these segments by rote at work, but you may not understand the reason for the distribution of these segments. Only when you understand it thoroughly can you play with it!
Why are the left ventricular long-axis views and the apical short-axis views divided into four segments each, instead of six segments each?
First, we need to understand three points
A, the septum and the interventricular wall are the same, only the designation is different, such as: anterior septum = anterior part of the septum = anterior interventricular wall.
B, the interventricular septum is divided into the upper and lower septum, and some people say the anterior and posterior septum (both are the same), the anterior septum is the anterior ventricular septum, the anterior interventricular wall; the anterior and posterior septum do not have a clear boundary.
C, only the apical septum, we call the septum, or called the septum (posterior septum, inferior septum) apical, other parts of the septum are called the anterior (upper) septum (interventricular wall) or posterior (lower) septum (interventricular wall), respectively
Second, the left ventricular long-axis section also has six segments, but the apical segment is called this: apical anterior wall (the real sense of the anterior wall, not the apical part of the anterior interventricular wall, the apical part is no anterior interventricular wall), apical inferior wall (not the apical part of the posterior wall, the apical part of the heart is no posterior wall)
Third, in the long-axis view of the left ventricle, the basal and middle segments of the septum are called the anterior interventricular wall (anterior or superior interventricular septum), and further down the anterior wall (the anterior wall in the true sense); the basal and middle segments of the posterior wall are called the inferior wall (the inferior wall in the true sense)
Why is this so?
A, first of all, we look at the anatomical basis of the interventricular septum, in the actual anatomy, the axial direction of the heart and the human body is about 45 degrees angle, and the interventricular septum is frontal plane, that is, in the left ventricular long-axis section, the essence of the “anterior wall” above the plane of the lower edge of the anterior papillary muscle is part of the interventricular septum, so called the anterior septum (anterior interventricular wall) The anterior septum (anterior interventricular septum) (superior interventricular septum).
The anterior edge of the septum is gradually curved downward to the apex of the heart, while gradually becoming narrower, and is a clockwise spiral (from the bottom of the heart downward view), so, first, the concave surface of the septum to the left ventricle, second, the upper left anterior is wider, third, the more narrow to the right anterior down, fourth, the apical part of the septum has become very narrow. This is the reason for the spiral conical shape of the septum.
Ultrasound basis: Because the septum is curved and spiral, in the left ventricular long-axis view, when the acoustic beam passes through the septum from the base to the apex, it first cuts to the basal and middle segments of the anterior septum, and then to the apical segment of the left ventricular anterior wall, so the “septum” we see in the apical part of the standard left ventricular long-axis is actually the septum The “septum” that we see in the apical part of the standard left ventricular long axis is actually a part of the septum (anterior septum) and not really the entire septum.
Where are the inferior and posterior walls of the heart?
The approximate extent of the inferior wall, mostly in the left ventricle and a small portion in the right ventricle, is separated by the inferior septum, which extends down to the apical part of the heart and tapers upward to the right posteriorly to near the base of the heart, as determined by the angle between the long axis of the left ventricle and the mid-missing surface of the body and the anatomy of the diaphragm, which means that the left posterior upper part is a smaller area of the posterior wall; the approximate extent of the posterior wall is from the base of the heart, medially to the inferior wall, laterally to the lateral wall, and inferiorly to the inferior border of the posterior papillary muscle. the inferior border of the posterior papillary muscle.
Therefore
in the short axis at the mitral valve level, to the anterior and posterior, in the following order: base of anterior wall – base of lateral wall – base of posterior wall – base of inferior wall – base of inferior septum – base of anterior septum
In the short axis of the papillary muscles, the horizontal short axis, to the back, is: the middle of the anterior wall – the middle of the lateral wall – the middle of the posterior wall – the middle of the inferior wall – the middle of the inferior septum – the middle of the anterior septum
However, the short axis of the apical level, to the back, is: anterior wall apical – lateral wall apical – inferior wall apical – septal apical (missing posterior wall and anterior septum)
The schematic diagram is as follows (posterior view)
Therefore, in the long-axis view of the left ventricle, in the two-chamber view and in the short-axis view of the apical part, the apical part shows the anterior wall and the inferior wall together (the other two are the septum and the lateral wall), which is the reason why the anterior wall (not the septum) and the inferior wall (not the posterior wall) are seen in the apical part of the standard left ventricular long-axis view
The following is a diagram of each section
Left ventricular long axis 4 segments
Mitral valve horizontal short axis 6 segments
Mitral papillary muscle short axis 6 segments
Apical short axis 4 segments
Apical 4-chamber heart 6 segments
Apical two-chamber heart (left atrioventricular) 6 segments
Correspondence between segments and coronary distribution in each section
Parasternal long-axis view: The anterior septal blood supply comes from the anterior descending branch. If the proximal septum has abnormal systolic activity, it indicates a proximal lesion of the anterior descending branch. The posterior wall of the left ventricle is usually supplied by the left gyrus branch.
Short-axis view: the anterior descending branch supplies the anterior septum and anterior wall; the posterior descending branch supplies the posterior septum and inferior wall. The posterior descending branch mostly originates from the right coronary artery, and the posterior descending branch originates from the gyral branch in left dominant cases. The left gyral branch supplies the posterior lateral wall.
Apical two-chamber heart: the posterior descending branch supplies 2/3 of the inferior wall of the left ventricle, the rest is supplied by the anterior descending branch, and the proximal basal segment of the anterior wall is supplied by the proximal end of the anterior descending branch
Apical four-chamber heart: the apical part and the distal 2/3 of the ventricular septum are supplied by the anterior descending branch, the proximal 1/3 of the ventricular septum is supplied by the posterior descending branch, and the lateral wall is supplied by a branch of the gyral branch.
In the new 17-segment segmentation method, the newly added segmental apical cap is usually supplied by the left anterior descending branch
Two other issues must be brought to your attention
(a) On the left apical two-chamber view, the anterior and inferior walls are seen; if the probe is rotated slightly at this point, it shows the aorta, which resembles a long ventricular long-axis view (which can be called an apical nonstandard left ventricular long-axis view), i.e., it changes from the original anterior and inferior walls to the anterior interstitial and posterior walls.
(b) In the standard four-chamber view, which shows the posterior septum and lateral wall, if the probe is pointed slightly in the direction of the base of the heart (with the acoustic beam upward), i.e., in the apical five-chamber view, the septum shifts from the original posterior septum to the anterior septum and the lateral wall to the anterior wall.
These two particular views are easily confused by the general public !!!
Complete the explanatory video: Echocardiographic left ventricular segmentation method (American Society of Echocardiography 16 segmentation method), http://v.blog.sohu.com/u/vw/4350280