GROSS ABDOMEN MODULE - under construction

General Introduction

From actual bodies almost all the ideas of anatomical theory developed, but to understand this theory it is easier to use lists and labelled diagrammatic PowerPoint images, which present a simplified view and one that ignores anatomical variation from one person to another. The purpose of the anatomy lab is for you to find out what bodies are really like to the extent that we can do this once they are dead.
Another linking of knowledge and experience comes when you join your cadaver-based knowledge with live surface anatomy, surgical exposure, imaging techniques, etc, on patients.
This guide to your lab experience relates certain PowerPoints used in the lecture to labelled views of lab dissections. The images are separate from the brief linking and explanatory text and you'll reach them via links. In this way, you do not have one huge file to download, and you can leave or move in the program at any time. But, remember - you are in a website, so use BACK, not the exit X, which will whisk you right out of this module.

However, what we are showing you here are images to prepare you for what to experience and learn in the lab. You absolutely have to put on the gloves, feel, and explore, moving organs out of the way, putting them back, using your mind all the time and talking things through with your clasmates at the table. Ideas on the experience and the thinking are at this site Cadaver
Read through it to prepare yourself.
In the lab, within your working group of three or four, someone needs to have brought a copy of Guy's Anatomy book, a list of the structures to be learned for the test, & whatever of this can usefully be printed out and brought. Although, the idea is to have most of this in your head when you come in. However, printing out the Figs in black and white of course loses the color used extensively to distinguish things. You can, later, go over the labels and leaders and restore them with colored highlighters.
For using this material at the computer, some may work from the screen just clicking the links, others may want a printed version to read along with going off for the images.


Gross dissection Views

The gross dissection images on this site were photographed in 2003 & 2004 by Dr Barbara Kraszpulska with the technical help of Jeffrey Altemus, under the auspices of the Department of Neurobiology & Anatomy, West Virginia University. She holds the author's copyright.

Dissection views

(i) That you can see inside someone in this manner is only thanks to his/her generosity in allowing this use of his body after death. Respect the person's intent that you should be able to learn so as to be better at knowing and helping the living.

(ii) The appearance of the embalmed tissues and organs changes over time, so that in the lab you may meet darker shades of tan and brown.

(iii) In order to view the structures, usually several layers of connective tissue have had to be removed, so the images do not show how well and tightly our organs are packed in and fastened together.

(iv) One's first thought should be on orientation - How is the person lying? Face down/up/ or on side? What region am I looking at, and from what direction? Front back, left side, etc. [Know the technical names, supine, left lateral, etc.]

The first image of a series has a white stick figure to indicate orientation. Thorax & Abdomen (anterior) - Orientation

(v) Later Figs then are labelled to show major structures, vascular and nervous structures, and other items of interest.
Set in the text close to a dissection view may be a link to a relevant Powerpoint Fig from the Theory lectures.

(vi) At home, the images may take up to a minute to download, depending on your connection to the Web. They are in .jpg format which needs a viewer of some kind (Paint, Adobe, Camedia, etc.).
If you save the images all to one folder on your own computer, your viewer subsequently will give you a comprehensive showing of thumbnails or files that you can select from rapidly. Although, the links from the master text will not work, you can print that out and read along while looking at the images. Later, when I'm sure of how many .ppt and .jpg Figs I need to use, I may number them consecutively to connect them better with the text.


How we'll handle the list of structures to be known for the lab differs from the Bones list. At the end of this module will be the complete list for you to go through to see if you have a clear mental image of what each structure looks like in the lab and what its relations are. But before then the list will be broken up into the structures for particular thoracic regions, starting with Thoracic wall.



NBAN 206 MODULE III
Lab assignments Taken from Guy Workbook Lessons 34, 35, 36 Use Marieb (text, Ch. 14) for additional information.

WALLS OF THE ABDOMEN (Lesson 34) rectus abdominus muscle external abdominal oblique muscle internal abdominal oblique muscle transverse abdominis muscle aponeurosis of external abdominal oblique m.

ABDOMINAL ORGANS AND MESENTERIES (Lesson 35) Mesenteries: mesentery (proper), mesocolon, visceral peritoneum, parietal peritoneum, peritoneal cavity, greater omentum

Stomach: fundus, cardia, lesser curvature, greater curvature, pylorus

Small intestines: duodenum, jejunum, ileum

Large intestines: vermiform appendix, cecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, sigmoid colon, rectum

Liver:
falciform ligament, round ligament, right and left lobes, portal area
Gall Bladder
Biliary system: common hepatic duct, cystic duct, common bile duct Additional large organs in the abdomen Diaphragm Kidneys and suprarenal glands Pancreas Spleen VESSELS OF ABDOMEN (Lesson 36) ARTERIAL BLOOD SUPPLY OF THE LOWER BODY (Lesson 36) Use Marieb (text, p. 344) for more information) ABDOMEN Descending abdominal aorta (gives off three larger arteries) Celiac trunk (to foregut derivatives) Superior mesenteric artery (to midgut derivatives) Inferior mesenteric artery (to hindgut derivatives) Renal aa. (to kidneys) Gonadal aa.(to gonads) Lumbar aa.(to posterior all of abdomen)

Introduction to the Abdomen

The abdomen is covered by skin, and a lot of fat, over the abdominal muscles. These will mostly have been dissected away leaving white fasciae (sheets of connective tissue), and brown muscles over and attached to the pelvis, bony rib-cage, and spine.
The multilayering characteristic of the chest continues into the abdomen. Be aware (i) that layers may have been removed so that the now topmost layer lay deeper in life, and (ii) that its position may be included in the name of the muscle or fascia, but (iii) the muscle has a characteristic orientation which helps to identify it. The layering and fiber orientation are very much in the surgeon's mind as she/he approaches deeper organs neeeding attention, but also that there a places where there is more connective tissue than muscle
As we go through the abdomen images, we shall be going from superficial to deep, until we have removed mesenteries, guts and stomach, and liver and are looking at the retroperitoneal structures, such as aorta, kidney and spleen.

Points to keep in mind for abdomen

The first few views of the abdominal wall will not all be in the same head-right orientation, so look at stick man to warn of head-left switches.

This view shows the outer abdominal wall after scraping away the fat under the skin. we see the white sheets of connective tissue - aponeuroses - into which the medial ends of the abdominal muscles insert. The orange arrow indicates the characteristic hands-in-pockets orientation of the external abdominal oblique MMs. Down the midline the white line alba can just be made out. Cutting through the aponeuroses exposes a little of the rectus abdominis MMs, and shows that the aponeuroses also act as the sheath for the rectus muscle. . Ext abdominal oblique MMs & Rectus sheath

Here the outer sheath has been reflected, exposing both rectus abdominis MMs, oriented parallel to the midline linea alba of dense connective tissue. . Rectus abdominis MMs & Linea alba

Severing the rectus muscles and lifting them back reveals the deeper posterior wall of rectus sheath, which consists of the aponeurosis of the internal abdominal oblique MMs. This muscle runs at a right angle to the external abdominal oblique M. . Aponeurosis of Internal abd obl MMs

Here the abdomen has been opened, and the omentum removed. It shows how the internal abdominal oblique MMs are likewise sandwiched between white aponeuroses. Note also the ugly yellow fat tags epoploic appendages/appendices that hang off the colon and help to identify it. . Internal abdom oblique M & Fat Tags

This is what ones sees on opening the abdomen. The large fatty greater omentum obscures most of the gut. We distinguish the sigmoid colon from the small intestine by the fat tags on the former. The diapragm has been pulled back to expose some of the liver (right) and the stomach (left).
The outside of all these organs constitutes the visceral peritoneum; the parietal peritoneum is the smooth lining of the abdominasl cavity, but 0nly labelled in one site. . Greater omentum & Peritoneum

The next dissection image (DI) marks the general territories of thorax and abdomen, plus the Lft & Rt pectoralis muscles. Anatomy from now on will be much about territories and boundaries.

This view is typical of abdomen: major structures have been moved (a retractor holds up the liver), or removed (the lesser omentum within the stomachs's lesser curvature). As always heeding the body's orientation, the view shows well the smooth parietal-peritoneal surface of the diaphragm; the quite small curving white stomach; and, hanging from its greater curvature, the fatty greater omentum hiding the gut. . Stomach & Greater omentum

The greater omentum leaves exposed some of the right-side large intestine. Also evident is that the large liver extends out of the right upper quadrant into the left, and the shiny(=slippery) parietal peritoneum lines the abdominal wall. . Liver and parietal peritoneum

In this new orientation, the connection of the greater omentum to the stomach has been destroyed, but the omentum's connection to the transverse colon can be seen. Also, other parts of the large intestine are visible, except for the v. appendix and descending colon. . Large intestine

The cecum was displaced medially on the last image. Here, it remains tucked down into the lower right quadrant. The omentum has been totally cut away to show the small intestine nestled into the large intestine - the snake at McDonald's . Small intestine

When the transverse colon is pulled down, the liver and stomach become visible, here brought more clearly into view by retracting the liver, which also exposes the green gall-bladder inferior to it Liver & gall-bladder

Here, the orientation has shifted again, and the transverse colon has been pulled up to expose most of the small intestine. Note how the ileum is recognized by connecting with the cecum (the ileocecal valve is marked with the yellow circle); most of the small gut is jejunum; and the short duodenum disappears retroperitoneally to join pyloric stomach (not seen). The sharp bend/turn in the large intestine by the liver is the hepatic flexure. . Regions of small intestine

This is the same view, but with the primary mesenteric vessels marked - Superior mesenteric artery & vein. Their branches disperse to small intestine, cecum, ascending colon, and most of the transverse colon. They were imbedded in the solid membrane of the mesentery proper, but this was dissected away to leave the vessels visible. The whiter arterial branches are much easier to see than the venous ones. . Superior mesenteric A & V

Here the guts and stomach have been removed to expose retroperitoneal structures, including the abdominal aorta slightly to the left of the midline. From the aorta in descending order are: the celiac trunk, immediately splitting into three AAs; closely followed by the superior mesenteric artery, and at a distance by the inferior mesenteric artery. Note how much larger is the superior mesenteric A in keeping with the size of its territory. . Celiac trunk and mesenteric AAs

The celiac trunk's branches are: the left gastric artery; the common hepatic artery (leading to the gastroduodenal artery and the proper hepatic artery; and the splenic artery. The 'gastro' component goes around the stomach to serve the greater curvature and omentum. . Gastric, hepatic & splenic AAs

The splenic artery wiggles on its way to the spleen, here lifted out of its normal protected site (white asterisk) within the left ribcage . Spleen & Splenic A

Here, the spleen is in place and almost out of sight, but the large splenic vein emerging from it can be seen. Another adjacent retroperitoneal structure is the whiteish, elongated, lumpy (lobulated) pancreas usually hidden behind the stomach - a thumb is retracting the stomach. The head of the pancreas has to be by the duodenum at he pyloric end of the stomach . Splenic vein & Pancreas

This new view shows the long, narrow, wiggly vermiform (wormlike) appendix attached to the medial side of the cecum. Many older people will have had theirs removed because of appendicitis. The site of the ileo-cecal valve is also marked. . Vermiform appendix