Abdomen and Pelvis

Objectives List structures found in the abdomen and pelvic region Differentiate between tissues and structures based on displayed density levels Identify various anatomy within the abdomen and pelvic region in sagittal, axial, and coronal planes Describe the locations of and relationships between anatomic structures After completing this topic, you should be able to: List structures found in the abdomen and pelvic region Differentiate between tissues and structures based on displayed density levels Identify various anatomy within the abdomen and pelvic region in sagittal, axial, and coronal planes Describe the locations of and relationships between anatomic structures

This video will highlight key information and structures of the abdomen and pelvic region. Although these regions are often imaged separately, there is no distinct landmark or structure that indicates the precise end of the abdomen and the beginning of the pelvis. Generally, the abdomen extends from the diaphragm superiorly, down into much of the false, or greater pelvis inferiorly.

Axial Coronal Sagittal These images show the three different planes of the abdomen. Axial images will always resemble circles. In the coronal images, the pelvis usually stands out. It is present in almost every coronal slice of the abdomen. Sagittal images always give you a side view. This is easy to remember because both side and sagittal start with the letter ‘s’. http://www.youtube.com/watch?v=d2_IY7Io0 go link for coronal image series http://www.youtube.com/watch?v=6bdxrpXuw3k&feature=related link for axial image series

The image on the left is a “scout” for the axial abdomen and pelvis slices covered in this video. The green line indicates the level of each axial slice shown. As we take a trip through this region, think of yourself as a tourist, learning about the important landmarks and structures of this area. This first slice is typical of the superior starting point for an abdominal CT. The liver usually begins to come into view at this slice level, <bring in arrow> along with the inferior ventricle portion of the heart. Note the white areas on the aorta which indicate calcification<bring in arrow> Liver Calcified aorta

Liver Aorta Stomach with contrast Lung Spleen Moving down a few slices, the most obvious structure is the liver, <bring in arrow> now occupying the entire right side of the abdomen. The calcified aorta <bring in arrow> is still visible in the middle, and now the stomach has come into view. <bring in arrow> The stomach contains contrast. The spleen <bring in arrow> is on the far left, and just inferior to it is the last bit of the left lung <bring in arrow> . In the image prior there was much more lung. Think about where more lung field would be present in the abdomen. Yes, you guessed it, at the top Liver Aorta Stomach with contrast Lung Spleen

At this level, the left kidney is now visible At this level, the left kidney is now visible. <bring in arrow> The kidney is one organ that is easily recognizable in sectional anatomy. What about the right kidney? In many people, although certainly not all, the left kidney is more superior than the right, which is displaced downward by the liver. Another important structure to recognize has come into view as well, the inferior vena cava, or IVC, <bring in arrow> next door to the aorta. IVC Left kidney

Bladder Bowel Psoas Common iliac artery Common iliac vein As we near the end of our tour of the abdomen and begin to venture into the pelvis, the scenery really starts to change. Let’s take a stop here at the approximate level of the ASIS. Some major structures to recognize at this level include the bowel, <bring in arrow> the urinary bladder, <bring in arrow> and the psoas muscles<bring in arrow> . Less distinct are the iliac veins<bring in arrow> and arteries<bring in arrow> . Common iliac artery Common iliac vein

sectional anatomy of the pelvis: male vs. female The male and female pelvis differ in size, shape, and organ content. Click on the link in red and visit the following website. Once you arrive, explore the different sections of both the male and female pelvis, paying close attention to differences in the size and shape of the bony pelvis, as well as the reproductive organs of the male and female. http://radiology.heinrich.ca/

Spleen Inferior Vena Cava Psoas Muscle Audio: Let’s take a moment to review. Can you list some of the key structures we’ve visited on our tour of the abdomen? (pause for 5-10 seconds?) How did you do? Learning landmark structures such as those presented in this topic, provide a foundation for building a more comprehensive knowledge of anatomy. Animation notes: red circles fade in as sentence begins. Pause for five seconds or so after asking question, then fade in answers on left. Psoas Muscle

Spleen Psoas Looking at this coronal view of the abdomen and pelvis, can you identify the circled structures? (pause for 5 seconds, then fade in terms). How did you? The more you study, the more familiar the anatomic neighborhood becomes. Soon, you won’t feel so much like a tourist, you’ll begin to feel right at home. Bladder