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.
Esophagus. Esophageal spasms are painful muscle contractions that affect your esophagus, the hollow tube between your throat and your stomach. Esophageal spasms can feel like sudden, severe chest pain that lasts from a few minutes to hours.Esophageal spasms usually occur only occasionally. But for some people, the muscle contractions are frequent and can prevent food and liquids from traveling through the esophagus.Esophageal spasms can lead to chronic pain and swallowing problems. Treatment for occasional esophageal spasms may not be necessary.sophageal spasms usually occur only occasionally. But for some people, the muscle contractions are frequent and can prevent food and liquids from traveling through the esophagus. Esophageal spasms can lead to chronic pain and swallowing problems.