TL;DR: A fontanel is a soft spot on a dog's skull that is often normal in small breeds, but you should seek veterinary care if the area bulges or if your dog shows neurological symptoms after a head injury.
What is a fontanel in dogs and puppies?
A fontanel, often referred to as a "molera," is a soft spot on the top of a dog's skull where the bony plates have not fully fused together. This condition is most common in toy and small breeds, such as Chihuahuas. In many puppies, these spots are normal and will gradually close as they mature, though in some dogs, they may remain open for life.
Is an open fontanel considered a medical emergency?
- The urgency level for an open fontanel is generally low, as it is often a known anatomical feature and not an immediate crisis.
- Because the brain is more vulnerable to injury in this area, you must exercise caution.
- Seek veterinary attention if the spot appears to be bulging.
- Consult a vet if your dog sustains a head injury.
- Watch for neurological symptoms such as seizures, circling, or extreme lethargy.
How does sending a photo help with the veterinary triage process?
- A clear image allows triage professionals to assess the size of the area and the condition of the skin over the fontanel.
- Visuals help determine whether the area looks typical for the breed or shows signs of concern.
- Photos can identify swelling or fluid buildup that might require a more urgent diagnostic workup.
Clinical Context (Merck Veterinary Manual)
Patent fontanelles, or soft spots on the top of the head, are sometimes present in dogs with hydrocephalus. Clinical signs of hydrocephalus usually indicate cerebral dysfunction and often progress, though some animals may remain asymptomatic. Imaging by ultrasonography through the fontanelle, CT, or MRI can provide the diagnosis, and CSF analysis should identify encephalitis. During a physical exam of a newborn puppy, a fontanelle, if present, should be small.
Chapter: Neurology, Surgery
Source: The Merck Veterinary Manual, 11th Edition (Page 1226)