If you're fond of dogs that have a "smashed in" face, then your pet likely falls into a special category of canine known as brachycephalic. The term comes from two Greek words: "brachy," which means short, and "cephalic," which means head.
These types of dogs have been bred through the generations to have a normal lower jaw in proportion to their body, and a compressed, or shorter, upper jaw. Because of selective breeding, these dogs also have developed a number of health conditions that may cause concerns.
Specifically, these dogs often have brachycephalic respiratory syndrome, a condition that affects different areas of the respiratory tract. Breeds most often affected are Boston Terriers, Bulldogs, Pekingese, Pugs and Shih Tzus. [...]
The medical term for pinched nostrils is stenotic nares and it is a common problem in many of the brachycephalic or pug-nosed dogs. These breeds seem to have a huge list of respiratory problems that can develop over time due to their short head formation and the compact nature of the respiratory system. Stenotic nares in themselves may not be problematic for the dog unless there are other complications that make breathing difficult for the pet.
The most common breeds affected by stenotic nares include Pugs, Boston Terriers, Pekingese, English Bulldogs, Boxers and Shih Tzus. These dogs are born with cartilage malformations in the nose that limit or restrict the opening of the nostril, slightly to greatly reducing the airflow through the nose. [...]
Perhaps one of the most difficult aspects of breeding for a particular look in a type of dog is that often the altering of the physical attributes of the dogs over time results in significant problems for future generations. This is perhaps most obvious with the inherited respiratory conditions which tend to be most pronounced in breeds that have been selective bred for short muzzles and pushed in faces. It is important to note that not all respiratory problems that can be inherited are solely caused by specific types of breeding programs. There are specific conditions that can occur within lines and breeds of dogs however these conditions are often not life threatening unless there are other complicating factors. [...]