What is Cast Syndrome in Orthopedics?

Instructor: Artem Cheprasov
Should you worry if you have a cast on your leg? Will you get cast syndrome? Find out, in this lesson. We're going to define and explain what cast syndrome really is.

What is Cast Syndrome?

Don't panic just yet! If you've got a leg cast or an arm cast you are not at risk for cast syndrome, otherwise known as superior mesenteric artery syndrome. This is a rare and potentially life-threatening medical condition that results in the compression of the duodenum.

Let's find out more about exactly what happens, why it happens, and what it causes in this lesson.


Before we can understand cast syndrome a bit better, we need to understand some very basic anatomy. In your abdomen, toward your back, courses the largest artery in the body. This artery is called the aorta. The aorta runs up and down your body in a vertical manner. So, it is like the vertical line at the 'back' of the letter K.

The aorta gives off a branch, called the superior mesenteric artery (SMA). This artery courses toward the front of your body in a downward direction, at a roughly 45-degree angle away from the aorta. So, this artery is like the small line going toward the bottom in 'K'.

This angle, obviously, creates a space between the aorta at the back and the superior mesenteric artery at the front. Can you see the space in between the vertical and downward line in 'K'?

In this space, part of the duodenum, called the transverse duodenum, passes through the abdomen. The duodenum is the first part of the small intestine. The duodenum connects directly to the stomach.

Anyways, if anything compresses the angle (makes it smaller) between the SMA and aorta to about 6-25 degrees, then logically whatever is in this space is going to get squeezed quite a bit! And what's going to get squeezed in this instance? The duodenum! And so you get yourself superior mesenteric artery syndrome, also called cast syndrome. This ends up intermittently or severely, fully or partially, obstructing the duodenum at this point.


It's called cast syndrome, or more traditionally body cast syndrome because one of the possible causes for such compression is the use of a body cast. However, this is by no means the only cause of this condition. Other causes include scenarios such as:

  • Anorexia. This leads to excess weight loss. The intra-abdominal fat that props up this angle disappears and the angle decreases, leading to the same problem.
  • Rapid growth in children. They may grow so fast that they don't gain enough weight in the process. This sort of mimics the anorexia situation above.
  • Trauma, which can forcibly shut the angle and thus compress the duodenum.
  • Scoliosis surgery, which may change the angle in questions as the spine is lengthened.

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