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one of the membrane-covered spaces remaining at the junction of the sutures in the incompletely ossified skull of the fetus or infant. Actually there are two soft spots close together, representing gaps in the bone structure which will be filled in by bone during the normal process of growth. The anterior fontanelle is diamond shaped and lies at the junction of the frontal and parietal bones. This fontanelle usually fills in and closes between the eighth and fifteenth months of life. The posterior fontanelle lies at the junction of the occipital and parietal bones, is triangular in shape, and usually closes by the third or fourth month of life. Though these “soft spots” may appear very vulnerable, they may be touched gently without harm. Care should be exercised that they be protected from strong pressure or direct injury.
Fontanelles. From Jarvis, 2000.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


(fon'tă-nel'), [TA]
One of several membranous intervals between the angles and margins of the cranial bones in the infant; they include the midline anterior and posterior fontanelles, and the paired sphenoidal and mastoid fontanelles. See: cranial fontanelles.
[Fr. dim. of fontaine, fountain, spring]
Farlex Partner Medical Dictionary © Farlex 2012


A non-ossified area of membranous bone, in particular of the skull in an infant. Fonticulus is the accepted Terminologia Anatomica name; fontanelle is widely preferred in the working medical parlance.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


(fon'tă-nel') [TA]
One of several membranous intervals at the margins of the cranial bones in the infant.
Synonym(s): fonticulus [TA] .
[Fr. dim. of fontaine, fountain, spring]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


, fontanelle (fŏn″tă-nĕl′) [Fr. fontanelle, little fountain]
Enlarge picture
Any of the tough, fibrous membranes lying between the bones of the cranial vault of a fetus or infant. Fontanels, colloquially known as soft spots, allow an infant's skull to be compressed during passage through the birth canal. The fontanels ossify generally by age two. See: illustration

anterior fontanel

The diamond-shaped junction of the coronal, frontal, and sagittal sutures; it becomes ossified within 18 to 24 months.

posterior fontanel

The triangular fontanel at the junction of the sagittal and lambdoid sutures; ossified generally by age one.
Medical Dictionary, © 2009 Farlex and Partners


a gap in the skull bone where the brain and its membranes are covered only by skin. Young human infants possess an anterior fontanelle between frontal and parietal bones on top of the head, and a posterior fontanelle between occipital and parietal bones at the back of the head.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005


One of several "soft spots" on the skull where the developing bones of the skull have yet to fuse.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Considering that Mercy's fontanels are open, and an ultrasound could be performed.
Trent that Timmy appeared to have hydrocephalus with a bulging fontanel. He said the peculiar appearance of his eyes, a "setting sun" sign, was consistent with hydrocephalus, as was the vomiting.
Most babies are born with six fontanels. The most noticeable soft spots appear on the top and in the back of the baby's head.
In the ROP position, the sagittal suture line will be felt obliquely (from 1 o'clock to 7 c'clock), and it will be possible to feel the bregma (larger front fontanel) at the top and to the side of the pubic bone (by 1 o'clock).
They may demonstrate other signs of increased intracranial pressure, such as bulging fontanels. Seizures occur in about one third of patients with bacterial meningitis, especially in pneumococcal meningitis.
Luckily, as delicate as babies appear, they and their special places, like their navels, fontanels, and genitalia, are actually quite sturdy.
A soft spot, or fontanel, is the pliant and somewhat mushy area on the top ofa newborn's head where the four bones that will make up her uppermost skull have not quite grown together.
Because in the neonate, many sutures and fontanels are still open and these can be used as acoustic windows to "look" into the brain.
Common signs observed in these patients were focal neurological signs in 1 (0.5%), bulging fontanels in 14 (7.3%), neck stiffness in 53 (27.6%), Kernig's sign in 26 (13.5%), Brudzincski's sign in 18 (9.4%), reduced or deteriorating level of consciousness in 4 (2.1%), dilated poorly reactive pupils in 2 (1%), hypertension in 1 (0.5%), and irregular respiration in 1 (0.5%) patient.
The variables included were the basic demographics and signs and symptoms like fever, vomiting, irritability, drowsiness, seizures, headache, photophobia, bulging fontanel, neck stiffness, signs of meningeal irritations like Kernig's and Brudzincski's sign and Glasgow Coma Scale (GCS) at the time of presentation.
The abnormal fontanel. Am Fam Physician 2003;67(12):25472552.