Zenker's diverticulum is the name of a pouch that forms in the throat due to a weak spot or split in the muscle wall. This disorder can cause a range of problems related to swallowing and the proper passage of food through the throat.
When a muscle is weakened or split, the tissue nearby can sometimes slide into the space created, causing the formation of a pouch or indentation. The word diverticulum (the plural of which is diverticula) refers to a pouch, sac, or indentation created by the herniation (weakening or splitting) of a muscle wall. Zenker's diverticula (ZD) are pouches or pockets that form in the pharynx, the passage of the upper throat that connects to the trachea and esophagus. They are typically found on the left side of the neck because the esophagus' slightly curved shape creates a space there.
The direct cause of ZD is most often the splitting or weakening of muscles in an area of the pharynx called the Killian triangle (these splits or weak spots are possible in other areas of the pharynx, too, but not as likely). It is not known what exactly causes the split in the first place, though doctors speculate that abnormal muscular movements during swallowing, muscle spasms (caused, for example, by gastroesophageal reflux disease), inability of the muscles to completely relax, or underlying abnormalities in the upper esophageal sphincter (the "valve" that opens and closes the path to the stomach) may be contributing factors.
ZD occurs in men more frequently than women, tends to effect people of Northern European heritage more often than people from other backgrounds, and almost always occurs in older patients.