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.
Esophageal cancer: A malignant tumor of the esophagus. The risk of cancer of the esophagus is increased by long-term irritation of the esophagus, such as from smoking, heavy alcohol intake, and Barrett esophagitis. Very small tumors in the esophagus usually do not cause symptoms.nfections of the esophagus can be caused by bacteria, viruses, or fungi, including: 1  Candida, a yeast infection. 2  Herpes, a viral infection.