Open Fontanels

by Jo Ann White

When puppies of various breeds (and human babies too) are born, the bony plates of the skull are separated and somewhat soft, allowing them to flex as the puppy passes through the birth canal. After birth, these plates gradually fuse and become rigid. The last place to fill in and solidify is the spot at the top of the skull where the four skull plates meet. If these plates do not fuse, we are left with a soft, unprotected spot at the top of the head that is called an open fontanel. In some very tiny breeds, particularly Chihuahuas, the fontanel may never close.

Very rarely, a puppy with an open fontanel may have a serious medical problem called hydrocephalus (water on the brain). Too much fluid within and around the brain creates pressure that may damage or prevent the development of critical brain tissue. A hydrocephalic puppy will usually exhibit symptoms such as seizures, blindness, lack of coordination, walking in circles, an enlarged dome, etc., by the time it is four months old. There is no treatment for hydrocephalus.

In a normal-sized Shih Tzu an open fontanel usually closes by the time the puppy is about four weeks old, and almost always by the time it is four months old. If it does not, it still may close later. A puppy with an open fontanel can live out a normal life with certain precautions. Responsible Shih Tzu breeders are very careful to place the rare puppy with an open fontanel in a home without other pets or small children, and insist that it not be bred. The new owners are cautioned to avoid careless grooming, hits to the head, or falls, as an injury to this unprotected spot could cause possibly cause serious brain damage. Special care must be taken because the puppy is totally unaware that it has any problem and is as lively and active as any other youngster.

The issue of open fontanels is just one more reason to avoid the undersized Shih Tzu sometimes marketed as “imperial” or “teacup” Shih Tzu. The AKC standard calls for Shih Tzu to be compact and solid, with a mature weight of 9 to 16 pounds. This is a breed that is a “big dog in a little package.” Almost always, adult Shih Tzu with open fontanels are undersized. Any adult Shih Tzu with an open fontanel, or one that has produced puppies with fontanels that never close, should not be bred. Additional information about undersized Shih Tzu and so-called “designer dogs” can be found on this American Shih Tzu Club website.

CREDIT: Reprinted from the June 2009 AKC Gazette with permission of the author.