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.
Scarring of the liver is the most common cause of esophageal varices. This scarring cuts down on blood flowing through the liver. As a result, more blood flows through the veins of the esophagus. The extra blood flow causes the veins in the esophagus to balloon outward. Heavy bleeding can occur if the veins break open.