The Discovery of a Bone in the Anterior Fontanelle of the Skull of the Sheep (Ovis aries) / Descubrimiento de un Hueso en la Fontanela Anterior del Cráneo de la Oveja (Ovis aries)

SUMMARY: A comparative study of the skull morphology was conducted using 270 prenatal and 750 postnatal skull samples from three breeds of sheep in Nigeria namely, Balami, Uda and Yankasa. A unique bone peculiar to the Yankasa breeds of sheep was found consistently at the centre of the anterior fontanelle in the young (day-old to 1 year). At two years of age and above, the bone was fused and disappeared completely. This brings the total numbers of the neurocranium bones of the skull in the Yankasa breeds to 8, as against the 7 bones documented in the ovine species. Due to the fact that this bone has not been described in the literature, we venture to name it the anterio-fontanelle bone (of Atabo).

Se realizó un estudio comparativo de la morfología del cráneo utilizando 270 muestras de cráneos prenatales y 750 postnatales de tres razas de ovejas en Nigeria, Balami, Uda y Yankasa. Un hueso único peculiar de las razas de ovejas Yankasa se encontró consistentemente en el centro de la fontanela anterior en las crías (de un día a 1 año). A los dos años de edad o más, el hueso se fusionó y desapareció por completo. Esto eleva el número total de huesos del neurocráneo en el cráneo en las razas Yankasa a 8, frente a los 7 huesos documentados en la especie ovina. Debido a que este hueso no ha sido descrito en la literatura, nos aventuramos a denominarlo hueso antero-fontanela (de Atabo).

Influence of unfused cranial bones on magnetoencephalography signals in human infants.

OBJECTIVE: To clarify the effects of unfused cranial bones on magnetoencephalography (MEG) signals during early development. METHODS: In a simulation study, we compared the MEG signals over a spherical head model with a circular hole mimicking the anterior fontanel to those over the same head model without the fontanel for different head and fontanel sizes with varying skull thickness and conductivity. RESULTS: The fontanel had small effects according to three indices. The sum of differences in signal over a sensor array due to a fontanel, for example, was < 6% of the sum without the fontanel. However, the fontanel effects were extensive for dipole sources deep in the brain or outside the fontanel for larger fontanels. The effects were comparable in magnitude for tangential and radial sources. Skull thickness significantly increased the effect, while skull conductivity had minor effects. CONCLUSION: MEG signal is weakly affected by a fontanel. However, the effects can be extensive and significant for radial sources, thicker skull and large fontanels. The fontanel effects can be intuitively explained by the concept of secondary sources at the fontanel wall. SIGNIFICANCE: The minor influence of unfused cranial bones simplifies MEG analysis, but it should be considered for quantitative analysis.

Stress and strain propagation on infant skull from impact loads during falls: a finite element analysis.

Background and Objective: To simulate infant skull trauma after low height falls when variable degrees of ossification of the sutures are present. Methods: A finite elements model of a four-week-old infant skull was developed for simulating low height impact from 30 cm and 50 cm falls. Two impacts were simulated: An occipito-parietal impact on the lambdoid suture and a lateral impact on the right parietal and six cases were considered: unossified and fully ossified sutures, and sagittal, metopic, right lambdoid and right coronal craniosynostosis. Results: 26 simulations were performed. Results showed a marked increase in strain magnitudes in skulls with unossified sutures and fontanels. Higher deformations and lower Von Mises stress in the brain were found in occipital impacts. Fully ossified skulls showed less overall deformation and lower Von Mises stress in the brain. Results suggest that neonate skull impact when falling backward has a higher probability of resulting in permanent damage. Conclusion: This work shows an initial approximation to the mechanisms underlying TBI in neonates when exposed to low height falls common in household environments, and could be used as a starting point in the design and development of cranial orthoses and protective devices for preventing or mitigating TBI.

Closure of the anterior and posterior fontanelle in the New Zealand population: A computed tomography study.

AIM: Significant ethnic variation has been demonstrated in the closure of the anterior fontanelle (AF); however, to date, this has not been investigated in the Maori/Pasifika population. METHODS: The computed tomography scans of 163 individuals (116 Maori/Pasifika and 47 New Zealand (NZ) European) aged between birth and 4 years were retrospectively analysed to investigate the surface area (SA) and time of closure of the anterior and posterior fontanelles in New Zealand. RESULTS: The Maori/Pasifika group showed clinical AF closure (SA < 114 mm2 ) rates of 25% at 4-6 months, increasing to 47% at 10-12 months and 80% at 13-18 months. The posterior fontanelle was clinically unfused in 17% of the Maori/Pasifika group aged <1 month and in 7% of the 1-3-month-old group. No cases of posterior fontanelle non-fusion were identified in the NZ European population. CONCLUSION: This study establishes normal values for AF size and closure frequency for the first time in the paediatric Maori/Pasifika population.

EEG in neonates: Forward modeling and sensitivity analysis with respect to variations of the conductivity.

The paper is devoted to the analysis of electroencephalography (EEG) in neonates. The goal is to investigate the impact of fontanels on EEG measurements, i.e. on the values of the electric potential on the scalp. In order to answer this clinical issue, a complete mathematical study (modeling, existence and uniqueness result, realistic simulations) is carried out. A model for the forward problem in EEG source localization is proposed. The model is able to take into account the presence and ossification process of fontanels which are characterized by a variable conductivity. From a mathematical point of view, the model consists in solving an elliptic problem with a singular source term in an inhomogeneous medium. A subtraction approach is used to deal with the singularity in the source term, and existence and uniqueness results are proved for the continuous problem. Discretization is performed with 3D Finite Elements of type P1 and error estimates are proved in the energy norm (H¹-norm). Numerical simulations for a three-layer spherical model as well as for a realistic neonatal head model including or not the fontanels have been obtained and corroborate the theoretical results. A mathematical tool related to the concept of Gâteau derivatives is introduced which is able to measure the sensitivity of the electric potential with respect to small variations in the fontanel conductivity. This study attests that the presence of fontanels in neonates does have an impact on EEG measurements.

Anterior fontanelle size among term neonates on the first day of life born at University of Gondar Hospital, Northwest Ethiopia.

BACKGROUND: Anterior fontanelle is the largest, prominent and most important fontanelle, which is used for clinical evaluation. It is mainly characterized by its size and shape variation and is possibly influenced by gender, race and genetics. Understanding the variation of anterior fontanelle is used for recognition of different medical disorders and abnormal skeletal morphogenesis. OBJECTIVE: To determine the mean size of anterior fontanelle among term neonates on the first day of life born at University of Gondar Hospital, Gondar Town, Northwest Ethiopia, 2018. METHODS: Descriptive cross sectional study design was undertaken in 384 term and apparently healthy neonates, using standard methods. Descriptive analysis, student t-test, one way ANOVA and Pearson correlation coefficient were implemented. RESULTS: In this study, the mean size of anterior fontanelle in term neonates was 3.00 ± 0.62 cm (range 1.70-5.50 cm). The mean size of anterior fontanelle was 3.10 ± 0.66 cm for males, and 2.88 ± 0.57 cm for females. There was statistically significant difference in anterior fontanelle size in neonates of different genders (p<0.001), mode of delivery (p<0.001) and duration of labour (p = 0.006). However, the size of anterior fontanelle was not significantly affected by the birth order, onset of labour and socio-demographic variables of the mother except occupation of the mother (p = 0.01). There was a significant positive correlation between the mean size of anterior fontanelle with birth weight (r = 0.11; p = 0.04) and head circumference (r = 0.17; p = 0.001). CONCLUSIONS: At term, male neonates had significantly larger anterior fontanelle than female neonates and anterior fontanelle size has a direct relationship with birth weight and head circumference.

Anterior Fontanelle Size in Healthy Indian Late Preterm and Full Term Newborns.

OBJECTIVE: To measure the size of the anterior fontanelle (AF) in healthy late-preterm and term newborns and correlate it with birth weight, gestational age, gender, occipito-frontal circumference, small for gestational age status and birth weight z-score. METHODS: This was an observational study carried out from October 2013 through April 2015 at a tertiary care hospital. Newborns ≥ 34 wk gestation were enrolled. Fontanelle edge was palpated with index finger and size calculated by adding anterior-posterior and transverse diameters and dividing by two. RESULTS: A total of 1010 neonates were enrolled. The mean AF size was 2.23 ± 0.52 cm (mean ± SD). There was a significant decrease in the size of the AF with advancing gestational maturity on one-way ANOVA (F = 31.30) (P < 0.001) and also by increasing birth weight (F = 20.34) (P < 0.001). There was no significant difference in the mean AF size between males; 2.21 ± 0.54 cm and females; 2.25 ± 0.55 cm (mean ± SD) (P = 0.575). There was a strong correlation between AF size with increasing birth weight; correlation (r) = 0.985. In small for gestational age neonates the AF was larger, 2.27 ± 0.55 (mean ± SD) and a strong correlation between birth weight z-score and AF size was noted (r = 1.012). CONCLUSIONS: The mean AF size in late-preterm and term Indian newborns in a mixed community hospital was 2.23 ± 0.52. A strong correlation was found between AF size with increasing birth weight and with birth weight z-score in small for gestational age babies.

Cord serum 25-hydroxyvitamin D is not associated with cranial anthropometrics in infants up to 6 months of age. An Odense Child Cohort study.

Skull changes are poorly described in vitamin D insufficiency [serum 25-hydroxyvitamin D (s-25(OH)D) 25-50 nmol/L]. We aimed to investigate factors associated with cranial anthropometrics in infants, especially s-25(OH)D. In infants 2.5-6 months old from the Odense Child Cohort, associations between cord and pregnancy s-25(OH)D and anterior fontanel area (n = 765), head circumference (HC, n = 1776) and head shape (n = 1527) were investigated along with other factors. Age was corrected for preterm birth. The mean (SD) s-25(OH)D in early pregnancy was 65.97 (21.33) nmol/L; late pregnancy 78.61 (27.18) nmol/L; and cord 47.1 (21.7) nmol/L. At median (IQR) age 3.7 (2.5-5.9) months, the fontanel area was 225 (0-1690) mm2, and mean (SD) HC was 41.5 (1.5) cm. Asymmetric/flat head shape was present in 846 infants (55.3%). No associations were found between cord, early or late pregnancy s-25(OH)D and any cranial measure by univariate or adjusted analysis. Among significant, independent associations in multivariate analysis, fontanel area was associated inversely with gestational age (GA); HC was associated directly with GA, maternal pre-pregnancy overweight and caesarean section and inversely with smoking; and asymmetrical head shape showed a novel association with male sex: adjusted OR = 1.54 (95% CI 1.25; 1.89), p < 0.001. Other associations with asymmetrical head shape included parity 3+, gestational age and maternal age 30+ years (all protective). In conclusion, neither pregnancy nor cord s-25(OH)D was associated with fontanel size, HC or asymmetrical head shape despite a high prevalence of cord s-25(OH)D < 50 nmol/L. Lower GA was associated with larger fontanel size, lower HC and asymmetrical head shape, and boys more frequently had asymmetrical head shape, probably due to heavier heads.

A comprehensive review of the anterior fontanelle: embryology, anatomy, and clinical considerations.

PURPOSE: Fontanelles are a regular feature of infant development in which two segments of bone remain separated, leaving an area of fibrous membrane or a "soft spot" that acts to accommodate growth of the brain without compression by the skull. Of the six fontanelles in the human skull, the anterior fontanelle, located between the frontal and parietal bones, serves as an important anatomical diagnostic tool in the assessment of impairments of the skull and brain and allows access to the brain and ventricles in the infant. METHODS: Using a standard database search, we conducted a review of the anterior fontanelle, including its embryology, anatomy, pathology, and related surgical implications. CONCLUSIONS: The diagnostic value of the anterior fontanelle, through observation of its shape, size, and palpability, makes the area of significant clinical value. It is important that clinicians are aware of the features and associated pathologies of this area in their everyday practice.

The effect of fontanel on scalp EEG potentials in the neonate.

OBJECTIVE: To define how fontanels affect scalp EEG potentials in neonates. METHOD: Realistic finite element method head models were generated with and without fontanels. The electrical activity of the whole cortex was simulated using distributed 54,620 concurrently active cortical dipoles with a uniform random distribution of current densities (0-40 µA/cm2). The overall effects of fontanels on scalp potentials were calculated from finite element forward solution in the vicinity the fontanel region by relative difference measure (RDM*) and magnification factor (MAG), and the skull conductivity was systematically varied from 0.003 to 0.3S/m. RESULTS: The neonatal scalp EEG topographies are comparable in models with and without fontanels, with highest amplitudes directly above the anterior fontanel. Quantitatively, comparison of these models elicits negligible differences (RDM*) ∼2% and MAG ∼1.0). However, fontanel contribution to scalp potential was shown to increase sharply with decreases in skull conductivity. CONCLUSIONS: These results suggest that fontanels may affect neonatal scalp EEG much less than traditionally assumed, and the effect is strongly dependent on skull conductivity. SIGNIFICANCE: Most neonatal EEG studies can be adequately performed without assuming distortions by fontanels.

Anterior fontanelle closure and size in full-term children based on head computed tomography.

INTRODUCTION: This study investigates radiographically acquired normative ranges of anterior fontanelle closure (AFC) and surface area (SA) in healthy full-term infants. METHODS: High-resolution head computed tomography (CT) scans were retrospectively reviewed for AFC and AF dimensions to allow approximation of AF SA. RESULTS: Between 15 and 23 head CT scans per monthly age-group (0-24 months) were reviewed, totaling 464 scans. AFC frequency increased steadily from age 10 (16%) to 20 months (88%), reaching higher than 50% at age 16 months (53%). The AF was closed in 3% to 5% of infants at 5 to 6 months. AF median SA increased from 769.3 mm(2) (age 0 months) to 1022.2 mm(2) (2 months), then declined steadily. CONCLUSIONS: This study provides reference charts detailing AFC frequency and AF SA as a function of age. Wide variability of AFC timing and AF size among healthy infants suggest that early or delayed AFC may represent normal variants.

Anatomoradiological identification of intrasutural bones for importance of cranial fracture.

AIM: Intrasutural bones are often found within sutures and fontanelles of the skull. It is important that the anatomy of these bones in the field of non-accidental injury with respect to medicolegal complications. Skull fracture lines are critical in their differential diagnosis, and the features of bone formations, their appearance and position give us a more definitive diagnosis. MATERIAL AND METHODS: Intrasutural bone location, its number and symmetry were investigated in totally 300 adult skulls. RESULTS: 27 intrasutural bones were identified as interparietal (2%), preinterparietal (3%) and sutural bones (4%) were in the lambdoid sutures. It was detected that the interparietal and preparietal bones were single, and the sutural ones were in a multiple number. The sutural bones were superposed in significant structures such as sagittal sinus and sinus sigmoideus. CONCLUSION: The ones that should be paid attention to in the differential diagnosis of the skull fracture lines are preinterparietal and interparietal bones in larger sizes. These findings prompted us to report these cases as their presence can lead to confusion in diagnosis in cases of skull fractures.

Size of the anterior fontanelle: three-dimensional measurement of a key trait in human evolution.

The anterior fontanelle (AF) is an integral element of the developing human infant craniofacial system. Consideration of the AF is crucial for assessing craniofacial growth, as altered development of this feature may indicate abnormal growth. Moreover, prolonged patency of the AF may represent a derived hominin feature. The AF is regarded as essential for fetal head molding during birth in humans, with deformation of the head during birth often necessary for successful delivery. However, the function of a patent AF among fossil hominins is unclear. Because the AF represents an important structure in both a clinical and evolutionary context, techniques for estimating the size of the AF must be accurate and reproducible. Therefore, we have developed a novel method for assessing surface area of the AF with the goal of creating a more accurate measure of this feature. In this study, we test the accuracy and repeatability of a novel three-dimensional (3D) method for assessing the size of the AF in human infants and compare the results obtained for surface area of the AF using the conventional and 3D methods.

Statistical characteristics of anterior fontanelle size at birth of term Sri Lankan new borns: a descriptive cross sectional study.

INTRODUCTION: Assessing the anterior fontanelle size is an important component of routine neonatal examination. For meaningful interpretation of fontanelle size, normal reference values are essential. Normal values for the fontanelle size in Sri Lankan newborns are not available. OBJECTIVES: To investigate characteristics of anterior fontanelle size at birth in Sri Lankan babies. METHODS: A descriptive cross sectional study was carried out between October and November 2010. Horizontal and vertical dimensions of the anterior fontanelle were measured in 2215 normal term babies, between 12 to 24 hours after birth. A practical and simple method was used to measure fontanelle size. Average fontanelle size was calculated by adding horizontal and vertical dimensions and dividing by two. RESULTS: Mean of the average fontanelle size for the total sample was 2.55 cm (for males 2.57 cm and for females 2.52 cm). Longitudinal dimension was significantly higher than the horizontal in both sexes (p<0.001). Frequency distribution curves of fontanelle size followed a normal distribution in both sexes. The ninety seventh centile and third centile for the average fontanelle size were 4.5 cm and 0.9 cm respectively. CONCLUSIONS: Babies with an average anterior fontanelle size more than 4.5 cm or less than 0.9 cm need further follow up. Further studies are needed to evaluate the accuracy of these cut off values.

[Changes of anterior fontanel size in children aged 0 - 2 years].

OBJECTIVE: To study the development of anterior fontanel(AF) in children less than 2 years of age. METHOD: The size of AF of the children under 2 years of age was measured. The criteria were: (1) All the children were singletons and term (37 weeks ≤ gestational age ≤ 40 weeks) at birth, birth weight > 2500 g. (3) Those with intracranial diseases (included trauma and asphyxia) and scalp hematoma were ruled out. (3) Healthy children (without intracranial disease, growth retardation, congenital syndrome or bone metabolic diseases such as rickets). RESULT: (1) The mean value of AF in neonates was 1.5 (0.3 - 2.5) cm, and the average of the AF at 1 month after birth was 2.2 cm, which was the largest one. The size of AF was 1.0 (0.3 - 2.0) cm at age 12 months, and 0.5 (0.3 - 0.7) cm at 24 months. (2) The percentage for the closure of the AF was 3% at 6 months, 26.5% at 12 months, and 93.0% at 24 months. (3) There were no gender differences in the size of the AF (P > 0.05). And the size of AF was not correlated with the development levels of weight, length, and head circumference (P > 0.05). CONCLUSION: (1) The size of AF at 1 month was maximum (2.2 cm), and then decreased by years. The AF was almost closed (93%) at 24 months. (2) There were no gender differences in anterior fontanel (P > 0.05). The size of AF was not correlated with the growth of weight, length, and head circumferences (P > 0.05). (3) The fontanel dimensions should be represented by oblique diameters of the fontanel in clinical pediatrics. (4) The AF closure time needs to be further evaluated in normal children.

Anterior fontanelle size in healthy Iranian neonates on the first day of life.

There is limited data in the literature on the normal size of the anterior fontanelle. This cross- sectional study was to determine normal values of anterior fontanelle size on the first day of life, using standard methods. Anterior fontanelle size was measured in 400 term and healthy neonates delivered at the Shariati Hospital, Tehran, Iran. Examination included assessment of head circumference, anterior fontanelle size, weight, length. Type of delivery was also recorded. The mean size of anterior fontanelle was 25.34 ± 13.27 mm, and it was established in both genders, 26.70 ± 13.19 mm in boys, and 23.67 ± 13.20mm in girls. A significant difference between the mean anterior fontanelle size in boys and girls was found (P=0.023). There was no significant difference in anterior fontanelle size between the infants born with a normal vaginal delivery and those with cesarean-section (P=0.08). There was found a significant negative correlation between the mean size of anterior fontanelle size with both weight and height (P<0.05). No significant correlation was found between mean size of anterior fontanelle and head circumference or with gestational age of infant (P≥0.05). Our results proved possible to define a references range and centile chart. The method used is simple and accurate and easy used in the routine neonatal examination.

Brain herniation in a neonate.

Brain herniation is generally thought to be unlikely to occur in newborns due to the presence of the patent fontanelles and cranial sutures. A review of the literature published from 1993 to 2008 via MEDLINE search revealed no reports on neonatal brain herniation from intracranial tumour. We report a preterm Malay male infant born via elective Caesarean section for antenatally diagnosed intracerebral tumour, which subsequently developed herniation. Cerebral magnetic resonance imaging showed features that were compatible with a large complex intracranial tumour causing mass effect and gross hydrocephalus. Tumour excision was scheduled when the infant was two weeks old. Unfortunately, on the morning of the surgery, he developed signs of brain herniation and had profuse tumour haemorrhage during the attempted excision. Histopathological examination revealed an embryonal tumour, possibly an atypical rhabdoid/teratoid tumour. This case illustrates that intracranial tumours in newborns can herniate and should therefore be closely monitored.

[Applied anatomy of the fontanelles]. / Anatomía aplicada de las fontanelas.

OBJECTIVE: To make a description of the anatomy of fontanelles and to update what is currently known about their applications. METHOD: 7 cadaveric heads, 2 dry skulls and 2 frontal bones of foetus were used, and 48 anterior fontanelles from paediatric patients with or without associated pathology were examined. Surgical cases and neurosonography were also used. All the structures were measured and subsequently analysed. RESULTS: The size, structure and limits of the fontanelles were evidenced in the cadaveric head and skulls, as well as the evaluation of paediatric patients and the size of their fontanelles in different pathologies. CONCLUSION: Owing to their anatomical characteristics, fontanelles are a true window to the inside of the skull, which determines their multiple clinical and surgical applications.

Anterior fontanel size in term and late preterm Hispanic neonates: description of normative values and an alternative measurement method.

We sought to determine anterior fontanel size (AFS) in Hispanic neonates and to compare two methods of measurement. The traditional method (TRAD) was defined as the sum of the longitudinal and transverse dimensions, divided by 2. Diagonal measurements (DIAG) were obtained between the estimated midpoints of the edges of the frontal and parietal bones, and the sum was divided by 2. Interobserver reliability was assessed in a subset of the study population. One hundred seventy neonates with gestational age 38.9 +/- 1.5 weeks were studied at a median age of 32 hours. Measurements by TRAD and DIAG (mean +/- standard deviation) were 22.5 +/- 7.9 mm and 20.9 +/- 6.7 mm, respectively ( P = 0.12). AFS was greater in males and in neonates whose mothers had longer duration of labor. Interobserver reliability was excellent for both methods. This study provides normative data for AFS using two methods in Hispanic neonates. A modest trend toward less variability with the DIAG method was noted. Male gender and longer duration of labor were associated with larger AFS.

[Effects of calcium and vitamin D supplementation on bone specific alkaline during pregnancy lactation and infant].

OBJECTIVE: To investigate the effect of calcium and vitamin D supplementation during pregnancy, lactation and infants on bone development of infant. METHODS: 1176 health infants aged 42-365 days and their mothers were recruited as subjects at Pediatric Department in Beijing Obstetrics and Gynecology Hospital during November 2006 to January 2008. Retrospective questionnaire was asked about calcium and vitamin D supplementation during pregnancy, lactation and infant. Blood bone-specific alkaline (BAD) and fontanel anterior (FA) of infant were measured. Chi2 test and logistic regression were used to analyze the research data. RESULTS: The chi2 test result showed that maternal supplementation with Ca and vitamin D during breastfeeding could decrease infant BAP significantly (P = 0.018), while supplementation during pregnancy could not (P = 0.154). The logistic regression result showed that infant supplementation with Ca and Vitamin D could decrease infant BAP significantly (P = 0.000), while infant feeding methods could not (P > 0.05). The FA size of infants aged < or =42 days had significant negative relationship with BAP (P = 0.017), and no relationship with Ca and vitmin D supplementation during pregnancy. CONCLUSION: Supplementation with Ca and vitamin D of mother during lactation and infant could significantly decrease infant BAD. The FA size could not indicate the infant calcium status.