Posterior View of the Anterolateral Abdominal Wall

00:01 Now, let's have a look at the anterolateral abdominal wall.

00:04 Drawing together the muscular arrangements around the arcuate line and the rectus sheath.

00:11 This can be a slightly complicated image to look at.

00:14 So what we've done is we've really climbed into the abdomen, we've climbed into the abdomen and we're looking at the anterior abdominal wall, but we're looking at it from the view of the stomach or the intestines.

00:26 So we're looking at the posterior surface of the anterior lateral abdominal wall.

00:31 So you can see various structures are located here.

00:34 So here, we can see, we have external oblique muscle.

00:40 So here we can have external oblique muscle it's being cut, and we're imagining that muscle is now going to curve anterolaterally around. We can see external oblique.

00:49 Here we can see internal oblique muscle, the cut layer of muscle before it runs anterolaterally around to the linea alba in the midline.

00:58 And here we can see transversus abdominis muscle.

01:02 You can see posteriorly, we have the aponeurosis of transversus abdominis.

01:07 Here as we move inferiorly, we have the arcuate line, because now rectus abdominis muscle has penetrated transverse abdominis aponeurosis.

01:18 It also would have penetrated remember, the posterior layer of internal oblique aponeurosis.

01:24 But now with a level of the arcuate line from this posterior view of the anterolateral abdominal wall, you can see how we have the aponeurosis of transverse abdominis, rectus abdominis penetrates it.

01:37 So we just see the rectus abdominis muscle.

01:41 Obviously, what we would have on here is transversalis fascia, blocking the view, but that's been removed.

01:47 The green horizontal line, It's a little bit below the umbilicus, we have the accurate line, and then we have rectus abdominis.

01:56 What we've just grade onto the screen there is transversalis fascia.

01:59 So here we can see no transversalis fascia.

02:02 And here we have transversalis fascia.

02:05 So that's now been laid on.

02:06 And remember that is the most posterior structure we've seen so far.

02:11 Here we have the umbilicus.

02:12 We have the round ligament of the liver.

02:14 We'll come back to that when we talk about the liver, but that's an immunological remnant.

02:18 We also have the median umbilical ligament, which you can see here, and that's again to do with the bladder during and biological development.

02:25 We also have on either side, the right and the left.

02:28 The right you can see it demarcated on the left as well as on the right, the right medial umbilical ligament.

02:34 This is a remnant of embryological development, and it's housing the obliterated umbilical artery, the umbilical artery was important during embryological development.

02:43 But here we can see as we're no longer attached to the mother's uterus, we can no longer need to have the umbilical artery, it's become obliterated, it's become fibrosed, and it's become the medial umbilical ligament.

02:55 Not to be confused with the median.

02:57 So median in the midline, working away laterally.

03:01 First, we encounter the medial umbilical ligaments.

03:04 And then within the inferior epigastric vessels, we find we have the lateral umbilical ligament.

03:10 So you can see there were the inferior epigastric vessels, they would form what's known as the lateral umbilical ligament.

03:17 If we were then to add on another layer posteriorly, and we'll talk about the peritoneum in a later lecture.

03:23 Again, you can see the umbilicus.

03:25 But now essentially, if we just go back, and we have all of these structures, which is slightly elevated, so they're forming a contour, alongside the posterior aspect of the anterolateral abdominal wall.

03:40 We have various raised contours.

03:42 So we have the median umbilical ligament, the medial and the lateral umbilical ligaments.

03:47 If we were to then just lay a tablecloth over though, we can actually see how they formed these quite, quite clear ridges.

03:56 So here again, we can see the median umbilical fold, we can see the medial umbilical fold, and now we can see the lateral umbilical fold, which we can see here housing the epigastric blood vessels that we mentioned previously.

04:09 So we've got 1, 2, 3. Median in the middle, then medial and then lateral, the umbilical folds. We can see that.

04:17 This then means we have these various spaces that are situated between these various elevations.

04:22 Supravesical, medial, lateral, and these are important again to help demarcate specific areas of the abdomen.

04:29 And we'll talk to those again later on.

04:33 So it's good to have an understanding of the abdomen and its various landmarks both on the external surface that you can see.

04:39 The mechanisms of the formation of the rectus sheath and how that gives rise to various surface landmarks, but on the internal surface, which are viewed from the inside of the abdomen.