In recent years, some taxonomic controversy has occurred over the genus of North American rat snakes. Based on mitochondrial DNA, Utiger et al. (2002) showed that North American rat snakes of the genus Elaphe, along with closely related genera such as Pituophis and Lampropeltis, form a monophyletic group separate from Old World members of the genus.
A pinched nerve is a type of injury or damage to a nerve or a group of nerves. The injury can result from compression, constriction, or stretching. A pinched nerve can lead to other conditions and cause temporary or permanent damage depending on the extent of the injury. pinched nerve is a type of injury or damage to a nerve or a group of nerves. The injury can result from compression, constriction, or stretching. A pinched nerve can lead to other conditions and cause temporary or permanent damage depending on the extent of the injury.
The esophagus is a muscular tube connecting the throat (pharynx) with the stomach. The esophagus is about 8 inches long, and is lined by moist pink tissue called mucosa.The esophagus runs behind the windpipe (trachea) and heart, and in front of the spine. Just before entering the stomach, the esophagus passes through the diaphragm. Esophageal ulcer: An erosion in an area of the lining of the esophagus. 2  This is often caused by chronic reflux. 3  Esophageal stricture: A narrowing of the esophagus. 4  Chronic irritation from reflux is the usual cause of esophageal strictures.