The Anatomy and Occurrence of Acid Reflux

What is the root cause of acid reflux? Too much gastric acid? An open cardia?

Some blame acid reflux on an overabundance of gastric acid, which, following this logic, must be neutralized. Well, this approach is wrong. We have seen and analyzed a host of gastroscopy reports, and only very few contain findings of "a large amount of secretion from the empty stomach” i.e. gastric juice.

The exact medical condition called acid reflux (or Gastroesophageal Reflux Disease – „GERD”) is the failure to shut the lower esophageal sphincter (also called the cardia) tightly, allowing gastric acid or its vapor to enter the esophagus. But this is only part of the big picture: if the gastric acid can enter the esophagus, it means the cardia does, indeed fail to form an impenetrable barrier between the stomach and the esophagus – but it does not automatically mean it always fails to do so. Hardly half of those aforementioned gastroscopy reports mention an “open” or “weakly shut” cardia. The other half claims that (the cardia): "closes properly"(...) yet the patient suffers from acid reflux. How is that possible? Well, those medical reports only capture a snapshot, a mere few minutes of the patient’s life.

The cardia is usually not continuously open. At times it is, allowing gastric acid or its vapor, to enter the esophagus. And the doctor will usually do little more than prescribe some kind of antacid or proton pump inhibitor (PPI) as a “treatment”. You can read more about them here.

What makes the cardia open at times, and why will it fail to shut properly?

The heart of the problem lies in the diaphragm.

The cardia is where the esophagus penetrates the diaphragm. The image shows the diaphragm in orange; the lower esophageal sphincter – the cardia – forms the upper boundary of the stomach. Below it there is, among other organs, the digestive tract; above it there are the heart and lungs.










The cardia is attached to the diaphragm, and the two affect each other. The image below allows a better view of the position of the stomach relative to the diaphragm. The circled area is the cardia. Whenever the pressure inside the abdominal cavity grows, the stomach is pushed upwards. Unfortunately, most people fail to realize it in time, noticing it only after a large meal, when their stomach is about to “rip”, tightening the abdominal wall and only allowing comfortable sitting with a straight back. If the growth in pressure would be apparent at an earlier stage, much fewer people would suffer from acid reflux.










If the diaphragm receives pressure from below, it will expand prohibiting the proper closure of the cardia.

Why does the diaphragm react to the growth of pressure inside the abdominal cavity so negatively?

The abdominal cavity is bounded by muscles and bones:


  • – The muscles of the pelvis at the bottom
  • – The lumbar spine and its muscles on the back side
  • – The layers of the abdominal muscle on the sides and the front side
  • – The diaphragm at the top




The pelvic muscles and those of the torso are active much more frequently than the diaphragm. And here I’m not referring to a deliberate training of those muscles, but rather everyday activities like getting out of the bed, walking or doing chores. In these situations the pelvic and torso muscles work much more intensively than the diaphragm.

When the pressure inside the abdominal cavity grows, this increased tension will press and deform the weakest barrier – the diaphragm – most easily. The diaphragm – which surrounds the cardia!

What do we use the diaphragm for – and what should we use it for?

We use the diaphragm to breathe. For infants most of the breathing is done by a technique called abdominal breathing, and only later do we – or most of us anyway – “lose the habit”. Some however, never do and continue to apply abdominal breathing into their adulthood – which is little more than panting. Abdominal breathing neglects the diaphragm, as a fraction of a normal person’s lung capacity is enough when doing less taxing everyday tasks.

Right now, for example, you are reading, which is a non-physical activity requiring only a minimal amount of breathing. Now, take a deep breath – as deep as you can. Can you feel how much more air you are able to inhale than you need when you are sitting or lying down? Well, inhaling to your full lung capacity also requires what is called shallow breathing which doesn’t require the use of the diaphragm, this is true – but the sole aim of this little experiment was to demonstrate how little air is enough when the body is resting, and that resorting to abdominal breathing as the prime inhaling method will leave the diaphragm weaker.

I think it’s easy to see that going to the grocery store down the corner is nothing as an exercise for the thigh muscles compared to doing 100 squats. Well, it is very similar with this panting-type abdominal breathing: it hardly strengthens the diaphragm...

A weak diaphragm will easily yield to pressure: it will deform and stretch, often PROHIBITING THE PROPER CLOSING of the cardia.

In the image below the black arrows indicate the upward pressure while the red arrows indicate the force exerted by the diaphragm pulling the cardia open:



The more frequently the diaphragm and abdominal pressure prohibit the proper closure of the cardia, the higher the chance of gastric acid or its vapor to enter the esophagus and the pharynx is, even potentially flowing back into the trachea, causing various unpleasant symptoms.



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