Surface Anatomy of the Abdominal Wall – Overview

by Craig Canby, PhD

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    00:01 Welcome to this lecture on an overview on the abdominal wall.

    00:06 This slide lists the objectives that you should be able to answer as a learner at the conclusion of this presentation.

    00:14 First, describe the surface anatomy of the anterolateral abdominal wall.

    00:19 Describe the planes and regions of the four quadrant and nine region pattern.

    00:25 List the regions where pain is referred by derivatives of the foregut, midgut, and hindgut.

    00:32 List the skeletal and muscular elements of the abdominal wall. List the layers of the abdominal wall from superficial to deep.

    00:41 List three important anatomic landmarks with respect to the dermatomes.

    00:47 And lastly, list the male and female major structures transmitted through the inguinal canal.

    00:56 We will then highlight the key messages from this presentation in a summary and then provide for attribution of the images that we'll use throughout this presentation.

    01:10 Alright here are body map to orient you to the areas that we're going to be covering today in this lecture.

    01:17 We will be looking at this area, the anterior abdominal wall. We will explore orientation to the lateral aspect of the wall.

    01:26 And then we'll also take a look at the posterior portion of the abdominal wall.

    01:33 This slide brings us to surface anatomy or the surface relief of the anterior abdominal wall.

    01:41 This is best demonstrated in a young well developed male with less than ten percent body fat.

    01:48 The landmarks that we're interested in are in the area of the rectus abdominis.

    01:55 The rectus abdominis underlies the skin and rectus sheath in this area as well as on the left side of the body.

    02:05 In the midline, we have the belly button or the umbilicus. And then above and below, but best seen above, you see this depression or this furrow and this corresponds to the linea alba.

    02:25 Additionally, we have an area here that represents a furrow or depression and as you proceed inferiorly toward the pubic bone you'll see that it curves inwards.

    02:37 Similarly, we have the same thing occuring on the opposite, rectus abdominis on it's lateral aspect and again it will curve inwards as you proceed inferiorly.

    02:49 This team arcades will represents the line refer to as the linea semilunaris And lastly, we see some furrows and they're orientated more transversly here within the skin overlying the rectus abdominis, these correspond to tendinous intersections.

    03:14 When we think about the anterior aspect of the abdominal wall, we can divide the anterior abdominal wall into quadrants.

    03:24 This is useful clinically in charting where a patient may be feedling abdominal pain.

    03:32 To form these quadrants, we need two lines. One is a vertical line, one will be a horizontal line.

    03:41 The vertical line is represented here. It is running within the linea alba proceed through the umbilicus inferiorly toward the pubic symphisis.

    03:53 The horizontal line will run also through the umbilicus, thereby intersecting with the vertical line at the perpendicular angle and then continue to the opposite side as well.

    04:07 Consequently, we now have a right upper quadrant, a left upper quadrant, a right lower quadrant, and a left lower quadrant.

    04:22 Underlying some of these quadrants would be principally the liver and gall bladder in the right upper quadrant.

    04:29 The liver does extend over to the left upper quadrant. We would have the spleen residing within this region.

    04:37 The portion of the stomach. In the right lower quadrant for example, we'd have the appendix and the caecum.

    04:46 And in your left lower quadrant underlying this particular region, we would have the descending colon and sigmoid colon.

    04:58 We can also describe the anterior abdominal wall into a nine region pattern.

    05:06 This is more complex. There are two vertical planes that will help define this nine region pattern and two horizontal planes. Those planes are shown in this particular illustration.

    05:21 We have the right mid clavicular plane being one of the two vertical planes.

    05:27 And then we'll have the left mid clavicular plane. The two horizontal planes will intersect the two vertical planes.

    05:37 The first horizontal plane oriented more superiorly here is referred to as the subcostal plane and it is running from the inferior margin the rib cage to the opposite inferior margin of the rib cage.

    05:54 The inferior horizontal plane that we see at this level is running from a bony projection on the iliac crest refer to as the tubercle and then will run to the opposite ilium where it has its associated tubercle. This is then refer to Apley as the intertubercular plane.

    06:17 As a result, the overlying the anterior and even the lateral abdominal wall of these two vertical and two horizontal planes, we now have the nine region of pattern.

    06:29 We have three regions in the upper area, shown here. We have three regions in the middle region or area.

    06:37 And we have three regions below. These are named. This is the right hypochondriac region.

    06:45 This is the epigastric region. This then is the left hypochondriac region.

    06:53 The middle regions, from the right side in the individual to the left side in the individual would be right flank or right lumbar, umbilical where you have the umbilicus and then you would have your opposite left flank or lumbar region.

    07:11 The inferior three regions shown here, again running from the individuals right to the left, this would be the right groin or right inguinal region. This is the pubic or hypogastric region.

    07:25 And then we have the opposite left groin or left inguinal region.

    07:34 This nine region pattern is useful in understanding referred pain.

    07:42 When we think about the development of the viscera that would be associated with your abdominal cavity the primitive gut tube is arranged into three regions called the foregut, the midgut, and a hindgut.

    08:02 Adult structures derived from the foregut would include the oesophagus, the stomach, liver, gall bladder pancreas, and the proximal portion of your duodenum.

    08:15 The midgut derives structures would include distal duodenum, all of the remainder of the small intestinal segments, the caecum, appendix, ascending colon, and about the proximal half of your transverse colon.

    08:33 And then the hindgut would give rise to the distal portion of your transverse colon, descending colon, sigmoid colon, rectum, and a portion of the anal canal.

    08:47 Pain from those gut-derived structures is referred to the various regions based on which part of the primitive gut tube it was derived from.

    08:58 So for example, the appendix which would reside in this particular region, the appendix is derived from the midgut and so typically then referred pain will be referred to the umbilical region.

    09:14 The gall bladder, will typically refer pain to the epigastric region.

    09:21 The pancreas can certainly have referred pain to the epigastric region as well.

    About the Lecture

    The lecture Surface Anatomy of the Abdominal Wall – Overview by Craig Canby, PhD is from the course Abdominal Wall.

    Included Quiz Questions

    1. Appendix
    2. Stomach
    3. Pancreas
    4. Liver
    5. Sigmoid colon
    1. LUQ
    2. RUQ
    3. RLQ
    4. LLQ
    1. Subcostal and intertubercular
    2. Right midclavicular and left midclavicular
    3. Subcostal and umbilical
    4. Right midclavicular and subcostal
    5. Left midclavicular and subcostal
    1. Hypogastrium
    2. Inguinal
    3. Right hypochondrium
    4. Left hypochondrium
    5. Epigastrium
    1. Epigastrium
    2. Umbilical region
    3. Right hypochondrium
    4. Left hypochondrium
    5. Hypogastrium

    Author of lecture Surface Anatomy of the Abdominal Wall – Overview

     Craig Canby, PhD

    Craig Canby, PhD

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    very well summaraized, and explained, the doctor did very well
    By Edgar B. on 06. February 2019 for Surface Anatomy of the Abdominal Wall – Overview

    i did very like how it was explained the anatomy, i enjoyed every single bit of the conference