Anterolateral Abdominal Wall: Overview

00:01 Hello, welcome to this topic, which is going to look at the anterior lateral abdominal wall, and specifically the various muscle layers that form this wall and how they are arranged.

00:12 So this is a really complex aspect of anatomy.

00:15 And there's lots of muscles that reside in the anterior lateral abdominal wall.

00:19 So let's have a look at really what I'm talking about.

00:22 So in this region, we're imagining the person is laying on their back and you're looking at them through their feet.

00:29 So they're laying on bed, they're laying on their back and you're standing at the foot end of the bed, so you're looking up through them.

00:36 And you can see the posterior aspect of the body is at the bottom of the screen, and the anterior aspect of the body is at the top of the screen.

00:44 It's important that you're familiar with that orientation.

00:48 So here we are looking at the surface anterolateral abdominal wall.

00:51 Skin, and then situated deep to that skin, we have a superficial layer of fascia which may contain various amounts of subcutaneous fat.

01:00 We then have a muscle layer, and you can see there there's four paired muscles.

01:05 So the same name for these muscles on both the left and right hand side.

01:09 And there's another muscle there that we can't quite see called pyramidalis and we'll come to that in a moment or two.

01:14 So we have the skin, the superficial fascia which contains some subcutaneous fat.

01:19 We have the muscle layer.

01:21 Then we have another layer of fascia which we call transversalis fascia.

01:25 We'll come to that in more detail later on.

01:27 And then deep to that, before we get into the abdominal cavity proper, we have the peritoneum, which goes on to form the peritoneal cavity.

01:35 And again, we'll talk about that later on as well.

01:38 The peritoneum is particularly complex.

01:40 So if we then just have a look at these individual muscle layers.

01:44 We can see we have a series of what are known as lateral or anterior lateral muscles that really start to laterally and make their way towards the midline and they typically come to the midline as layers of tendon.

01:58 Here, we can see most superficially, we have external oblique.

02:02 Deep to that we have internal oblique, and then we have transverse abdominis.

02:06 So we have three layers of these flat muscles that start laterally, and then curve anteriorly towards the most midline aspect towards the midline of the body, where they actually converge in the midline.

02:21 The muscles themselves don't reach the midline, but they give rise to a tendon, which we call an aponeurosis.

02:26 Again, we'll come to that in a moment or two.

02:29 Then running down vertically through the abdomen, on the anterior aspect, we have these anterior vertical muscles, and these are called rectus abdominis.

02:39 So a general outline there of the musculature on the anterior aspect of the abdominal wall.