The esophagus is a muscular tube that connects the mouth and the stomach. Food does not just fall from the mouth through the esophagus and into the stomach. The pharynx and walls of the esophagus propel food to the stomach by rhythmic waves of muscular contractions called peristalsis. When the esophagus is not in use, these sphincters close so that food and stomach acid do not flow back up the esophagus from the stomach to the mouth. During swallowing, the sphincters open so food can pass to the stomach.

"In the resting state, the esophageal body is normally collapsed, and the UES and LES are closed to prevent retrograde flow of esophageal and gastric contents." This description indicates that between swallows the esophageal lumen is collapsed (apposed walls) rather than held widely open, and both sphincters are closed at rest, limiting passive movement of contents into the stomach.

A muscular ring at the top of the esophagus, called the upper esophageal sphincter, controls the flow of food from the throat to the esophagus. The esophagus is a muscular tube that connects the mouth and the stomach. Rings of muscle contract and relax to allow food and liquids to pass through the upper and lower portions.

The upper esophageal sphincter (UES) … is a 4-cm segment of the digestive tract that separates the esophagus from the pharynx. … At rest, these cartilages press against the spine, **closing the potential space of the UES**. … The UES serves to protect the esophagus and stomach from aerophagia and the larynx from gastric and esophageal reflux while facilitating normal swallow function.[1]

"Therefore when the lumen was fully closed on the catheter the diameter of the lumen was taken as 0 mm (lumen occlusive), rather than 3.2 mm. ... Finally, isometric relaxation ... allows the lumen to return to its original quiescent state." The authors describe mechanical states of the esophageal body, including periods of **luminal occlusion** and a **quiescent state** after peristalsis, implying that at rest the lumen can be closed or nearly closed except when distended by a bolus or air.

"In the resting condition, the esophageal body has a small amount of tone, but it is largely quiescent and may contain small amounts of air and reflect intrathoracic pleural pressures." This GI Motility overview notes that at rest the esophageal body is quiescent and can contain small amounts of air, meaning the lumen is not an actively sealed tube along its whole length and some gas can be present despite sphincter closure.

Think of swallowing as a journey that foods and liquids take to your stomach. There are three main stops along the way: your mouth (oral cavity), throat (pharynx) and the food tube that connects to your stomach (esophagus). Your esophagus squeezes the food or liquid down in a wave-like motion (peristalsis) until it reaches your stomach.

“The two sphincters maintain **tonic closure** and augmented reflex closure of the sphincter mechanism. They both **relax upon swallowing** but can also relax without a swallow, as a part of the reflex called transient LES relaxation (TLESR).” “For the transport of ingested contents into the stomach, **relaxation of both the LES and the diaphragmatic sphincter is essential**.” This indicates that at rest the lower end is kept closed by tonic sphincter contraction; fluid passage into the stomach requires active sphincter relaxation plus opening.[3]

"Under normal conditions, the LES remains tonically contracted with an intraluminal pressure of about 30 mmHg. ... The LES typically relaxes to a pressure close to the intragastric pressure (approximately 3.0 mmHg). ... TLESR is the spontaneous relaxation of the LES in the absence of swallowing. ... Vomiting, belching, and physiologic reflux in normal subjects occur through the mechanism of TLESR." This StatPearls review clarifies that the **lower esophageal sphincter (LES)** is tonically closed at rest but undergoes **transient relaxations** independent of swallowing, allowing antegrade or retrograde flow, so it is not continuously closed at all times when not eating.

Muscles at the **top and bottom of your esophagus** play an important part in the process. … When no food or liquid is coming its way, **it usually stays shut to prevent stomach acid and digestive juices from getting into your esophagus**. … When there’s no food or liquid in sight, **it stays closed**. Once inside your esophagus, waves of muscular contractions (peristalsis) push the food down into your stomach.

“In the **resting state**, the esophageal body is flaccid and **collapsed**, and the upper and lower esophageal sphincters (UES and LES) are **closed** to prevent air entry and gastric reflux.” “Bolus transport requires coordinated **UES opening**, peristaltic contractions of the esophageal body, and **LES relaxation and opening**.” This recent review confirms that at rest the lumen of the body is collapsed while both sphincters at the ends are closed; transit into the stomach depends on sphincter relaxation, not passive dripping.[10]

“Normally, the **upper and lower sphincters are closed except during swallowing**, which prevents constant entry of air from the oral cavity or reflux of stomach contents.” This teaching text describes the esophagus as a muscular tube whose **ends are sealed by sphincters at rest**, while the body between them serves as the conduit when opened by swallowing-related peristalsis.[4]

"Both the UES and LES are tonically contracted at rest. The closed state for the UES is a result of continuous neural excitation, with a small passive component to tone. ... The resting tone of the LES is typically between 15 and 45 mm Hg ... LES relaxation occurs not only in response to swallowing but also in response to esophageal distention (secondary peristalsis) or without peristalsis." This chapter on the esophagus states that both the **upper** and **lower esophageal sphincters** are closed at rest, but emphasizes that LES relaxation can occur outside of swallowing, indicating intermittent opening even when not actively eating.

The upper esophageal sphincter relaxes and opens to allow food and liquids to pass into the esophagus. Afterward, the cricopharyngeus muscle closes back up to prevent any regurgitation back up into the throat. If the coordinated muscle movement timing is slightly off, liquids and even food may end up going down the windpipe instead of the esophagus, a situation known as aspiration.

"Normal esophageal function involves coordinated peristalsis that moves food down to the stomach. The lower esophageal sphincter is a muscle located at the junction between the stomach and the esophagus and has to relax appropriately for the food to enter the stomach. Motility disorders can occur if normal peristalsis is disrupted or if the relaxation of the LES is impaired thereby causing food to get stuck or stay in the esophagus for too long." The American College of Gastroenterology explains that the LES must relax to permit bolus passage and that impaired relaxation can trap material in the esophagus, reinforcing that a resting, tonically contracted LES normally blocks passive flow into the stomach unless it relaxes.

Your esophagus is made of a series of sphincters that open and close to help you swallow. This is why you can even drink water upside down. After that initial swallow, the throat continues to push the food down to the stomach through a process called peristalsis.

The esophagus is the muscular tube, about 8 inches in length, which connects the throat to the stomach. … An esophageal stricture occurs when the esophagus **becomes narrower at a certain point or points**. This narrowing leads to difficulty swallowing, eating, and drinking. It can also make a person more likely to choke. The stricture may become so severe it eventually causes a **complete obstruction**.

Achalasia is a motility disorder that affects muscle function when the nerves in the esophagus degenerate. As a result, **the muscles in the esophagus stop working, and the valve at the bottom of the esophagus does not open**. Normally when a person swallows, a reflex **relaxes the lower esophageal sphincter and the esophagus muscles begin to move food** toward digestion. … If a patient has achalasia, **the lower esophageal sphincter does not open appropriately and the body of the esophagus does not squeeze food down in a coordinated way**, leading to regurgitation and inability to empty contents into the stomach.

"Disorders of esophagogastric junction (EGJ) outflow occur when there is a failure of the LES to relax to allow a food bolus to pass." Medscape’s overview of EGJ outflow disorders notes that failure of LES relaxation prevents bolus passage, implying that a normally closed LES is a functional barrier that must open for material to move into the stomach, rather than a conduit that allows liquid to drip down freely at rest.

Our major findings were that cold water reduced strength of the peristaltic wave in healthy subjects and NOD patients, whereas it had no effect on achalasia patients. The study confirms that water interacts with esophageal motility; it does not describe the esophagus as permanently closed when not swallowing.

The esophagus is a muscular tube that connects the mouth to the stomach and is the conduit for food bolus to pass from the throat to the stomach. An **esophageal stricture is a narrowing of the esophagus** (see figure). … The most common cause of an esophageal stricture is long‑standing gastroesophageal reflux disease (GERD), where **stomach acid backs up from the stomach into the esophagus** and causes esophageal inflammation, which can lead to scarring and narrowing over time.

The esophagus has an **upper esophageal sphincter up here and the lower esophageal sphincter where the esophagus meets the stomach** which keep the ends of the esophagus closed most of the time. … The walls of the esophagus **are squeezed together by the smooth muscle there and that has to relax for anything to pass through**. … These two sphincters … when you’re eating food and drinking they need to relax to allow whatever you’re swallowing to pass through the esophagus … The rest of the time **they’re closed**. … High pressure in the abdomen is likely to **squeeze closed the walls of the esophagus because there’s nothing in it**; why would it be open?

“The esophagus is a **25-cm long muscular tube** that connects the pharynx to the stomach.” While this entry focuses on gross anatomy, standard anatomical descriptions treat the esophageal lumen as **collapsed at rest**, opening with peristaltic waves rather than being a rigidly patent channel that would allow fluid to drip passively without sphincter relaxation.[9]

Esophageal manometry studies show that between swallows the esophageal body typically exhibits low pressure with the walls apposed (a collapsed lumen), while the upper and lower esophageal sphincters maintain higher resting pressures and act as barriers. High-resolution manometry and barium swallow imaging demonstrate that small amounts of saliva or refluxate can be present in the esophageal lumen and that transient lower esophageal sphincter relaxations and swallow-induced relaxations allow contents to enter or leave the stomach even when a person is not actively eating a meal.

There is a peristalsis to swallowing, a natural reflex that not only pushes the fluid forward but also protects from getting any fluid into the trachea.

Although at rest, the **rat esophagus is tensed anisotropically in situ**. Resting length between the dots was 4.80 ± 0.76 mm. After CT removal, 4.77 ± 0.78 mm. After transections to free the esophagus, 3.42 ± 0.97 mm. This indicates that even at rest the esophageal wall is under tension and shortens when freed, suggesting **baseline smooth‑muscle tone rather than a flaccid, fully open tube**.

Esophageal strictures have many causes. … In laymen’s terms, **self dilation is manually stretching your esophagus yourself**. It is done with a “dilator” that you carefully insert and gently push into your throat until it passes through the connection where your esophagus was reattached to your redesigned stomach. **This stretches your esophagus out.**

“The lower esophageal sphincter is a ring of smooth muscle between the esophagus and stomach. It **stays tightly closed**, relaxes during swallowing, and prevents stomach contents from flowing back into the esophagus.” This popular explanatory post summarizes the standard view that the LES is tonically closed at rest, blocking spontaneous downward or upward flow at the gastroesophageal junction.[8]