Soft spot - sunken
Key points
- Sunken fontanelles describe a concave deformity of the "soft spot" in an infant.
- The skull is made up of many bones, 7 in the skull itself and 14 in the facial area.
- A sunken fontanelle CAN BE A MEDICAL EMERGENCY and should be evaluated promptly by a physician.
- The medical history will be obtained and a physical examination performed.
Alternative names
Sunken fontanelles; Fontanelles - sunken
Definition
Sunken fontanelles describe a concave deformity of the "soft spot" in an infant.
Considerations
The skull is made up of many bones, 7 in the skull itself and 14 in the facial area. They join together to form a solid, bony cavity protecting the brain and supporting the structures of the head. The areas where the bones join together are called the sutures.
The bones are not joined together firmly at birth. This allows the head to accommodate passage through the birth canal. The sutures gradually accumulate minerals and harden, firmly joining the skull bones together. This process is called ossification.
In an infant, the space where two sutures intersect form a membrane-covered "soft spot" called a fontanelle (fontanel). The fontanelles allow for growth of the skull during an infant's first year.
There are several fontanelles that are normally present on a newborn's skull, primarily at the top, back, and sides of the head. Like the sutures, fontanelles gradually ossify and become closed, solid, bony areas. The posterior fontanelle (in the back of the head) usually closes by the time an infant is 1 or 2 months old. The anterior fontanelle at the top of the head usually closes sometime within the range of 7 - 19 months.
The fontanelles should feel firm and very slightly concave to the touch. A noticeably sunken fontanelle is a sign that the infant does not have enough fluid in his or her body.
Common Causes
- Dehydration
- Malnutrition
- Normal variant
Call your health care provider if
A sunken fontanelle CAN BE A MEDICAL EMERGENCY and should be evaluated promptly by a physician.
What to expect at your health care provider's office
The medical history will be obtained and a physical examination performed.
Medical history questions documenting sunken fontanelles in detail may include:
- When did you first notice that the fontanelle looked sunken?
- How severe is it? How would you describe it?
- Which "soft spots" are affected?
- What other symptoms are also present?
- Has the baby been ill, especially with vomiting, diarrhea, or excessive sweating?
Written and revised by
Andrey Nailor, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.