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What Is Situs Solitus?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Situs solitus is a medical term indicating that all the abdominal and chest organs are in their expected positions, and are correctly oriented. The opposite is situs inversus, where the positions of the organs are flopped throughout the abdomen, creating a mirror image of what should be present. The position of the abdominal viscera can become important for activities like surgery, collecting biopsy samples, and assessing a patient with health problems that may be related to organ positioning.

In some cases, the positions of the organs are mixed up, and their positioning is described as situs ambiguus, referring to the fact that some organs are correctly positioned, while others are not. This can potentially pose a problem, as the organs fit together like the pieces of a puzzle in situs solitus, and switching their positions randomly could create problems. The patient might have difficulty with breathing, digestion, and other activities, for instance.

Many doctors depend on prenatal ultrasounds to monitor fetal progress.
Many doctors depend on prenatal ultrasounds to monitor fetal progress.

In a very special form of situs ambiguus known as dextrocardia, all the organs are in the correct place except for the heart, which is moved to the right side of the chest. This may sometimes be described as dextrocardia with situs solitus, as a note that all the other organs are where they should be. Swapped organ positioning can be a cause for concern if it interferes with organ function.

The causes of abnormal organ positioning have to do with errors in fetal development, when budding stem cells fail to migrate into situs solitus.
The causes of abnormal organ positioning have to do with errors in fetal development, when budding stem cells fail to migrate into situs solitus.

When the organs are positioned in situs solitus, the heart, a bilobed lung, spleen, stomach, and aorta are located on the left side of the body. The right houses the trilobed lung, gallbladder, and liver. These organs can be seen on a medical imaging study, which can allow a doctor to take note of any that may have migrated out of position. Such studies may be ordered before surgery to learn more about the nature of an injury or issue, and to confirm that the organ is where the surgeon expects it to be. Otherwise, the surgeon might make an incision and encounter something unexpected.

Medical imaging tests can allow a doctor to take note of migrating organs.
Medical imaging tests can allow a doctor to take note of migrating organs.

The causes of abnormal organ positioning have to do with errors in fetal development, when budding stem cells fail to migrate into situs solitus. This is a complex and detailed process, and occasionally mistakes happen. These are not necessarily predictable or preventable. In some cases, they are associated with larger medical problems, including in some instances abnormalities that may be incompatible with life. Prenatal ultrasound can provide some information about fetal development and may help care providers prepare for issues that may need treatment shortly after birth.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

KaBoom

I wonder how most people with situs inversus totalis find out they have it. It seems like sometimes situs inversus doesn't really interfere with the day to day functioning of the organs. So there wouldn't really be any cause for alarm. I guess people mostly find out when they're getting other medical stuff done.

In fact, I bet there are people out there with situs inversus that don't even know they have it!

strawCake

@Azuza - Yeah, I'm sure a lot of people don't fit the situs solitus definitely completely. I personally think dextrocardia sounds kind of interesting.

It's been my experience that most people don't know exactly where most of their organs are. For instance, I could not tell you where my gallbladder or my liver is located. However, everyone knows where the heart is traditionally located.

People put their hand over it to do the Pledge of Allegiance all the time. It must be weird to not have your heart in the "normal" place. Imagine trying to explain to a kid with dextrocardia that you put your hand over your left side because your heart is there, when theirs is not!

Azuza

When I took anatomy and physiology, I learned that anomalies in organ placement are fairly common among humans. Many people do not have abdominal situs solitus, for sure.

In fact, I myself have a retroverted uterus (this basically means my uterus is facing the wrong way.) As far as I know, all my other organs are in the right place though, so I don't have anything as extreme as situs inversus. However, I'm not sure my organ placement would be considered a perfect situs solitus either. Either way, it's never adversely affected my health.

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    • Many doctors depend on prenatal ultrasounds to monitor fetal progress.
      By: Valeriy Velikov
      Many doctors depend on prenatal ultrasounds to monitor fetal progress.
    • The causes of abnormal organ positioning have to do with errors in fetal development, when budding stem cells fail to migrate into situs solitus.
      By: blueringmedia
      The causes of abnormal organ positioning have to do with errors in fetal development, when budding stem cells fail to migrate into situs solitus.
    • Medical imaging tests can allow a doctor to take note of migrating organs.
      By: Maurizio Milanesio
      Medical imaging tests can allow a doctor to take note of migrating organs.