Area Of Foramen Magnum Research Articles

Morphometrie study of foramen magnum in human dry skulls

Abstract Background : Anthropologists are often faced with the task of assigning sex to remains that are incomplete, fragmented or damaged as may result from incidents such as mass disasters, airplane crashes, fire, explosions or physical violence. The size of foramen magnum does not change after puberty, not related to age then after. It is this part of the cranial base which can withstand fire explosions as the area is covered by large amount of soft tissue. Hence the foramen magnum was considered for studying the sexual differences in skull. Aims : To analyse the morphology and morphometry of foramen magnum, and the impact of these variables on sex determination of skull. Materials and Methods : 68 male and 68 female adult dry skulls were used for the study. The shapes of foramen magnum were studied. Results : In total, oval was the most common shape comprising of 61.76%, 16.17% arrow head, 11.76% irregular and 10.29% round. The sagittal diameter was 33.0 [28-40] mm in males and 33.0 [28-43] in females and transverse diameters of foramen magnum were 27[21-31] in males and 26.0[23-33]mm in females. Area of foramen magnum was calculated using Radinsky and Teixeria formulae and foramen magnum index was calculated. Mean, standard deviation and median [where ever required] were calculated. Student t test and Mann Whitney U test/ T test were applied. We did not find significant difference between male and female values. Conclusion : Our study did not demonstrate statistically significant difference in expression of sexual differences in the foramen magnum. However if detailed analysis is done with greater sample size by discriminant function analysis, it may prove useful in predicting sex in severely fragmented cranial bases.

Sexual dimorphism of foramen magnum using Cone Beam Computed Tomography

ObjectivesThe aim of this study was to evaluate whether the foramen magnum (FM) dimensions could be used for sex determination using the Cone Beam Computed Tomography (CBCT). MethodsTwo hundred and sixty six CBCT full Field Of View (FOV) scans (111 males and 115 female subjects) of the skull were retrospectively selected and the FM length, width measured on reconstructed axial cross section by two observers using the CS 3D imaging software at a slice thickness of 300 μm and the FM area subsequently calculated using two established formulae by Routal and Teixeira. All data were subjected to descriptive and discriminant functional analysis to validate the expression of sexual dimorphism in the metric parameters of FM. ResultsUsing the FM dimensions the overall accuracy rate of sex determination was 66.4%. Out of these, 70.3% of males and 62.6% of females were sexed correctly. The best parameter for sex determination was the Area of the FM. In addition, the accuracy rate of sex prediction using the Area dimensions (Teixeira's formula) was 66.4%, same as that of all the four FM parameters used together. ConclusionThis study validates that there is statistically significant expression of sexual differences in the foramen magnum region, which may prove useful and reliable in predicting sex in partial skull remains by discriminant function analysis when other methods tend to be inconclusive. It suggests the reliability, usability and accuracy of CBCT in forensic identification.

Human Foramen Magnum Area and Posterior Cranial Fossa Volume Growth in Relation to Cranial Base Synchondrosis Closure in the Course of Child Development.

To date, no study has compared the evolution of the foramen magnum area (FMA) and the posterior cranial fossa volume (PCFV) with the degree of cranial base synchondrosis ossification. To illustrate these features in healthy children. The FMA, the PCFV, and the ossification of 12 synchondroses according to the Madeline and Elster scale were retrospectively analyzed in 235 healthy children using millimeter slices on a computed tomography scan. The mean FMA of 6.49 cm in girls was significantly inferior to the FMA of 7.67 cm in boys (P < .001). In both sexes, the growth evolved in a 2-phase process, with a phase of rapid growth from birth to 3.75 years old (yo) followed by a phase of stabilization. In girls, the first phase was shorter (ending at 2.6 yo) than in boys (ending at 4.33 yo) and proceeded at a higher rate. PCFV was smaller in girls (P < .001) and displayed a biphasic pattern in the whole population, with a phase of rapid growth from birth to 3.58 yo followed by a phase of slow growth until 16 yo. In girls, the first phase was more active and shorter (ending at 2.67 yo) than in boys (ending at 4.5 yo). The posterior interoccipital synchondroses close first, followed by the anterior interoccipital and occipitomastoidal synchondroses, the lambdoid sutures simultaneously, then the petro-occipital and spheno-occipital synchondroses simultaneously. The data provide a chronology of synchondrosis closure. We showed that FMA and PCFV are constitutionally smaller in girls at birth (P ≤ .02) and suggest that a sex-related difference in the FMA is related to earlier closure of anterior interoccipital synchondroses in girls (P = .01). AIOS, anterior interoccipital synchondrosesFMA, foramen magnum areaLS, lambdoid suturesOMS, occipitomastoidal synchondrosesPCFV, posterior cranial fossa volumePIOS, posterior interoccipital synchondrosesPOS, petro-occipital synchondrosesSOS, spheno-occipital synchondrosisyo, years old.

Foramen magnum as a tool for sexual dimorphism: A cone beam computed tomography study.

(1) To evaluate dimensions of the foramen magnum (FM) among males and females and to establish its role in sexual dimorphism using cone beam computed tomography (CBCT). (2) To evaluate sagittal diameter, transverse diameter, area, and circumference of FM among males and females. Two hundred and eighty CBCT scans (140 males and 140 females; age range, 20-80 years) were selected for this study. The sagittal diameter, transverse diameter, area, and circumference of FM were measured, and data were subjected to discriminant analysis for the evaluation of sexual dimorphism. The area of FM was the best discriminant parameter which is used to study the sexual dimorphism with an overall accuracy of 72%. It can be concluded that the reconstructed CBCT image provides valuable measurements for the FM and could be used for sexing even when other methods are inconclusive.

Analysis of morphology of foramen magnum in Indian population

IntroductionThe foramen magnum is a unique and complex neuroanatomical structure. This is an important landmark of the skull base for neurosurgical procedures. The aim of this study is to analyze the morphometry pertaining to variations of the shapes and sizes of foramen magnum separately for males and females of Indian population along with comparing antero-posterior and transverse diameters available in literature and to bring out associated clinical implications. MethodsThirty-five dry skulls (13 females and 22 males) have been examined for morphometric variations of foramen magnum. The surface area of foramen magnum was calculated manually using graphical method. The importance of morphometry and clinical significance of foramen magnum has been established by available literature. ResultsMean antero-posterior diameter and transverse diameter of foramen magnum are 33.8±02.5mm and 28.2±02.6mm, respectively. The minimum, maximum and mean areas of foramen magnum in assorted skulls are 434mm2, 902mm2 and 648.5±112.2mm2, respectively. Foramen magnum index in assorted skulls vary from 1 to 1.45. DiscussionThe dimensions of foramen magnum, separately for males and females in the Indian population, have been analyzed for the first time. This analysis will be of paramount importance for clinicians in surgical procedures around this region.

MORPHOMETRIC EVALUATION OF THE FORAMEN MAGNUM AND VARIATION IN ITS SHAPE AND SIZE: A STUDY ON HUMAN DRIED SKULL

The foramen magnum is an important landmark located in the posterior part of the cranial base formed by the occipital bone. The purpose of this study was to evaluate the measurements of the foramen magnum in human dried skull and to note the variations in the shape and size of the foramen magnum. Additionally area and index of the foramen magnum were also calculated. Fifty human dried skulls of unknown age and sex were obtained from the department of CMCH Bhopal and FHMC Tundla. Foramen magnum were examined macroscopically for their different shapes. Anteroposterior and transverse diameters, foramen magnum area & foramen magnum index were measured. The foramen magnum shapes were determined as round shaped in 22%, oval shaped in 16%,egg shaped in16%, and irregular in18%,tetragonal in 12% penta and hexagonal 8% each. The mean A-P and transverse diameters of the foramen magnum was determined 38.75mm and 33.44mm respectively. In 4%of skull, the occipital condyle was observed to protrude in to the foramen magnum. The mean foramen index and foramen magnum area were 87.68 & 970.57mm². The data obtained may be useful to the neurosurgeon in analysing the morphological anatomy of craniovertebral junction in trans condylar approach for brain stem lesion.

Binary Logistic Regression Analysis of Foramen Magnum Dimensions for Sex Determination.

Purpose. The structural integrity of foramen magnum is usually preserved in fire accidents and explosions due to its resistant nature and secluded anatomical position and this study attempts to determine its sexing potential. Methods. The sagittal and transverse diameters and area of foramen magnum of seventy-two skulls (41 male and 31 female) from south Indian population were measured. The analysis was done using Student's t-test, linear correlation, histogram, Q-Q plot, and Binary Logistic Regression (BLR) to obtain a model for sex determination. The predicted probabilities of BLR were analysed using Receiver Operating Characteristic (ROC) curve. Result. BLR analysis and ROC curve revealed that the predictability of the dimensions in sexing the crania was 69.6% for sagittal diameter, 66.4% for transverse diameter, and 70.3% for area of foramen. Conclusion. The sexual dimorphism of foramen magnum dimensions is established. However, due to considerable overlapping of male and female values, it is unwise to singularly rely on the foramen measurements. However, considering the high sex predictability percentage of its dimensions in the present study and the studies preceding it, the foramen measurements can be used to supplement other sexing evidence available so as to precisely ascertain the sex of the skeleton.

Revisiting the far lateral approach in the treatment of lesions located at the craniocervical junction—Experiences from West China hospital, Sichuan University, Chengdu

Abstract Far lateral approach is a modification of the traditional lateral suboccipital approach that provides adequate exposure of the ventral craniocervical junction. Lesions located at ventral aspect of brainstem and foramen magnum areas like the lower clivus and premedullary area, intradural segment of the vertebral artery and its branches, including the posteroinferior cerebellar artery, the lower cranial and upper cervical nerves can be accessed through far lateral exposure. Between January 2011 and June 2014, 17 patients with lesions located at the ventral aspect of brainstem and foramen magnum areas were treated in our institution using a far lateral approach. We reviewed the nature of lesions, treatment strategy and outcomes in those 17 patients with the approval of institutional review board. There were 10 female and 7 male patients with age ranging from 6 to 58. Pathological entities comprised 11 meningiomas, 2 subarachnoid cyst, 2 epidermoid cysts, 1 vertebral aneurysm and 1 brainstem glioma. All patients recovered well after surgery without severe complications. In conclusion, far lateral approach provides an optimal exposure to the ventral aspect of brainstem and foramen magnum area which is sufficient for total removal of anteriorly placed well circumscribed lesions with zero retraction of neural axis.

MORPHOMETRIC EVALUATION OF FORAMEN MAGNUM IN DRY HUMAN SKULLS

The foramen magnum is an important landmark in the posterior part of the cranial base, which is largely formed by the occipital bone. The dimensions of the foramen magnum are clinically important because of the vital structures passing through it. We studied thirty six dry human skulls of known sex and measured anteroposterior and transverse diameters with the help of Vernier caliper. Additionally, surface area and Index of foramen magnum were also calculated. Oval shape is the main type of morphological variant found in this study. The transverse diameter of the foramen magnum was in a range of 25.75-34.25mm in males, whereas it was between 26-31.75mm in females. The anteroposterior diameter was in a range of 35 to 39.75mm in males while it was 29.5 to 34.75mm in females. The mean area of foramen magnum in males was 876.88±88.83mm whereas it was 776.87±68.51mm in females. In contrast to the area, the mean foramen magnum index was higher in females (89.01±6.84mm) compared to males (81.75±5.99mm) and this difference was also statistically significant (p<0.01). The prospective study will help surgeon for reference value for determining feasibility of transcondylar surgical approach, which are being done in an increasing trend in recent times for brain stem lesion.

Skull Base Morphology in Fibroblast Growth Factor Receptor Type 2-Related Faciocraniosynostosis

Children with faciocraniosynostosis present skull base abnormalities and may develop hydrocephalus or cerebellar tonsils ectopia (CTE). Several pathophysiological hypotheses were formulated in the past decades to explain these associations. However, no study has described in a genetically homogeneous population with confirmed fibroblast growth factor receptor type 2 (FGFR2) mutation eventual correlations between skull base abnormalities and hydrocephalus or CTE. To illustrate these features in children <2 years of age with a genetically confirmed FGFR2-related faciocraniosynostosis. We measured the foramen magnum area (FMA) and its sagittal and transversal components: the right, left, and mean area of the jugular foramen; the posterior fossa volume; and the cerebellar volume on preoperative millimetric computed tomography scan slices in 31 children with an FGFR2 mutation (14 with Crouzon syndrome, 11 with Apert syndrome, and 6 with Pfeiffer syndrome). They were compared with 17 children without synostosis. All children were <24 months of age. We correlated all these measures with the presence of hydrocephalus or CTE. We observed a significantly small FMA in children with Crouzon (P = .03) and in children with Pfeiffer (P = .05) resulting from a reduced sagittal diameter (P = .02 for Crouzon and P = .002 for Pfeiffer). Hydrocephalus was associated with small FMA (P = .02). The jugular foramen area, posterior fossa volume, and cerebellar volume were not associated with hydrocephalus or CTE. Hydrocephalus and CTE were statistically associated (P = .002). Hydrocephalus in FGFR2-related Crouzon and Pfeiffer syndromes is statistically associated with a small FMA. Hydrocephalus is statistically associated with CTE.

Morphology of the foramen magnum in syndromic and non-syndromic brachycephaly.

The shape and size of the foramen magnum (FM) can be altered in craniosynostoses. However, few studies have investigated these changes. In this paper, we investigate the morphology of the foramen magnum in syndromic and non-syndromic brachycephaly. Surface area, anteroposterior (AP) diameter, and transverse diameters of the FM were measured on high-resolution CT scans in children with Crouzon (25), Pfeiffer (21), Apert (26), Saethre-Chotzen (7) syndromes, and isolated bicoronal synostosis (9) and compared to an age-matched control group (30). A significantly smaller FM surface area was observed in Crouzon (6.3 ± 1.7cm(2)) and Pfeiffer (6.4 ± 2.3cm(2)) syndromes as compared to the control group (7.4 ± 1.3cm(2), p = 0.006 and p = .017, respectively). In comparison to the control group, no statistically significant alteration in FM surface area was noted in patients with Apert, Saethre-Chotzen, or isolated bicoronal synostosis (p = 0.37, p = 0.71, p = 0.40 respectively). The transverse diameter of FM was significantly smaller in Crouzon, Pfeiffer, and Apert syndromes compared to the control group (p = 0.005, p = 0.002, p = 0.03 respectively). In Saethre-Chotzen and isolated bicoronal synostosis, no difference in transverse diameter was demonstrated. Among all groups, only Crouzon syndrome showed reduced anteroposterior diameter as compared to controls (p = 0.005). In Pfeiffer and Apert syndromes, there was elongation of the shape of the FM with a relatively narrowed width as demonstrated in a significantly increased AP to transverse diameter ratio (p = 0.002 and p = 0.019, respectively). The FM shape and area is significantly altered in fibroblast growth factor receptor (FGFR)-related brachycephaly syndromes (Crouzon, Pfeiffer, and Apert), whereas in patients with Saethre-Chotzen syndrome (TWIST-1 mutation) and isolated non-syndromic bicoronal synostosis, the shape and mean FM area was not statistically different from that of normals. This study brings to light the important role of FGFRs on FM growth and shape. TWIST-1 mutation (Saethre-Chotzen syndrome) does not appear to have an important effect in shaping the FM.

Foramen Magnum Meningioma: A Rare Case Report

Background: Foramen magnum meningiomas are challenging tumors, requiring special considerations because of the vicinity of the medulla oblongata, the lower cranial nerves, and the vertebral artery. After detailing the relevant anatomy of the foramen magnum area, we will explain our classification system based on the compartment of development, the dural insertion, and the relation to the vertebral artery. Method: A 35 years age lady with foramen magnum meningioma was operated at the Department of Neurosurgery, Bangabandhu Sheikh Mujib Medical University 6 months back. A case report was taken before surgery and 6 month follow up was done after operation. Conclusion: As foramen magnum meningioma is very difficult to approach, with the help of microscope with proper training. We can remove completely without any deficit.DOI: http://dx.doi.org/10.3329/cmoshmcj.v13i3.21031

Evaluation of foramen magnum in sex determination from human crania by using discriminant function analysis

Background: Many studies have been conducted on different populations on sexual dimorphism with respect to the cranial base. The present research was undertaken to study the accuracy and reliability of the foramen magnum in sex determination by using discriminant function analysis. Methods: 140 adult skulls (70 of either sex) were included in the study. Length, breadth index and area of foramen magnum were subjected to discriminant function analysis. Results: The accuracy of sex classification was up to 75.7% using a single variable. The least value was obtained from the index of the foramen magnum i.e. 57.9%. Three discriminant function equations were calculated based on these measurements. In stepwise analysis, breadth of foramen magnum was found to be more discriminating variable providing an accuracy of 75.7%. Conclusion: It can be concluded from the results that the measurements of foramen magnum of cranium provides valuable results and suitable for sex determination when other methods are inconclusive.

Morphometric Analysis of Foramen Magnum for Sex Determination in Karnataka

In most of the day today forensic practice the skeleton will be incomplete and makes gender identification difficult. Many of craniofacial skeletal structures are damaged in mass disasters; natural or manmade, making it difficult to determine the gender. In such cases the skull base and the occipital bone protected by virtue of its anatomical position and packed with large amount of soft tissue, which makes an access for sex assessment. The most conspicuous feature of the cranial base is the large foramen magnum (FM). Length and breadth of the FM was measured using Vernier calipers and the area of FM was calculated. The length, breadth, and area of FM were found to be larger in males than females and were statistically significant. Using discriminant function accuracy of sexing using FM parameters analyzed and found that Morphometric analysis of FM for sex determination should be used only as a supportive finding in estimation of sex of skeletal remains of skull.

Anatomical variations of the human occipital condyles

Occipital condyles, located at the inferior sides of lateral parts of occipital bone, are important structures that connect the cranium and the vertebral column. Their size, shape, location and, also, their congruence with superior articular facets of the atlas vertebra are of great importance for the stability of craniovertebral junctions. The progress in medical diagnostic and surgical techniques in the area of foramen magnum, requires the knowledge regarding anatomical aspects of this region. The purpose of this study was to evaluate the measurements of the occipital condyles, as well as to analyse the variations in the shape of the condyles and their position in relation to the foramen magnum. This study included 25 adult human skulls (11 male and 14 female) from the Osteological collection of the Department of Anatomy at Medical Faculty in Novi Sad. Nine parameters, which define morfological properties of the occipital condyles, were measured using Vernier caliper. Also, the shape and location of the condyles, as well as the narrowness of the foramen magnum were described. Our findings show that length of the left occipital condyle, as well as distance between the posterior top of the left occipital condyle and basion are statistically greater in male crania, comparing to female crania. According to the shape of the occipital condyles, we classified them in seven groups. Predominant type is oval shaped. The condylar foramen is bilaterally present in 36 % and the occipital condyles bilaterally protrude the foramen magnum in 40 % of analyzed crania. Morphometric analysis of the occipital condyles showed variations in their size, shape, presence of condylar canal and relation to the foramen magnum.

Morphometric study of Foramen Magnum at the base of human skull in South Gujarat

The foramen Magnum is a large opening in the occipital bone of the cranium. The dimensions of the foramen magnum are clinically important because vital structures passing through it may endure compression such as in cases of foramen magnum herniation, foramen Magnum meningiomas and foramen magnum achondroplasia. We studied one hundred dry, adult human skull of unknown sex and measured antero- posterior and transverse diameter with the help of vernier caliper. Additionally surface area of foramen magnum was also calculated. The mean antero-posterior diameter of the foramen magnum was 40.2mm(range 26-40mm) and the transverse diameter was 28.29mm(range 21.5-33.5mm). The mean surface area of foramen magnum was 755.37mm.The knowledge of dimensions of foramen magnum will be helpful radiological diagnostic procedures and neurosurgical procedures to approach in the region of Foramen Magnum. Considering above mentioned importance, this study is worthwhile. The foramen Magnum(FM) (Latin: 'great hole') is a large opening in the occipital bone of the cranium. Its transverse diameter is rather less than one third of the distance between the mastoid processes. The anterior border of the foramen magnum is formed by basilar process of the occipital bone, the lateral border by the left and right ex- occipitalis and posterior border is formed by the

The Foramen magnum in isolated and syndromic brachycephaly

Though the foramen magnum (FM) is often altered in complex craniosynostosis, no study analysed the FM dimensions in patients with brachycephaly specifically. We measured the FM area, sagittal and transverse diameters on preoperative CT scans in patients with bicoronal synostosis (n = 40) and age-matched control group (n = 18). Our study included 16 children with FGFR3 p.Pro250Arg mutation (mean age 6.1months), 10 with TWIST-1 mutation (mean age7.6months) and 14 patients with isolated bicoronal synostosis (mean age 6.1). We observed a significantly smaller FM area in FGFR3 group compared to control group and isolated brachycephaly group (p = 0.001 and p = 0.038, respectively). The mean FM area in FGFR3 group was 426.13mm(2) (p = 0.001), while in TWIST-1 group was 476.34mm(2) (p = 0.103), and in isolated brachycephaly group 489.43mm(2) (p = 0.129) compared to control group: 528.90mm(2). The posterior segment of the sagittal diameter of the FM and its width as well as the bi-interoccipital synchondrosis diameters were significantly smaller in FGFR3 group compared to control group. In TWIST-1 group, the only altered dimension was the FM anterior segment of the sagittal diameter (p = 0.008). We did not observe any significant alteration of FM in patients with isolated brachycephaly compared to control group. The FM area is significantly altered in FGFR3-related brachycephaly, whereas in patients with Saethre-Chotzen syndrome (TWIST-1 mutation) the mean FM area is similar to control group. This study confirms the importance of FGFRs on FM growth whereas TWIST-1 seems to have a minor role.

Craniometric Analysis of Foramen Magnum for Estimation of Sex

Human skull is shown to exhibit numerous sexually dimorphic traits. Estimation of sex is a challenging task especially when a part of skull is brought for medicolegal investigation. The present research was planned to evaluate the sexing potential of the dimensions of foramen magnum in forensic identification by craniometric analysis. Length and breadth of the foramen magnum was measured using Vernier calipers and the area of foramen magnum was calculated. The length, breadth, and area of foramen magnum were found to be larger in males than females. Sexual dimorphism index was calculated to estimate the sexing potential of each variable. The study observations are suggestive of the limited utility of the craniometric analysis of foramen magnum during the examination of skull and its parts in estimation of sex. Keywords—Forensic Anthropology, Skeletal remains, Identification, Sex estimation, Foramen magnum. I. INTRODUCTION STIMATION of the sex of the skeletal remains is an essential element of any medicolegal investigation. Human skeleton shows sexually dimorphic traits, and estimation of the sex of skeletal remains is thus, based on morphological and morphometric examination. Sexing accuracy of the human skeleton varies for the different bones and in different population groups. Human skull is considered as one of the most reliable bones for sex differentiation (1). Previous studies have used different measurements on the skull to estimate its sex accurately (2)0(5). During high impact and severe disruptive injuries, only fragments of bones may be available for examination. Estimation of sex becomes challenging when only a part of skull is brought for examination and hence, a need to derive standards for sex estimation from different regions of the skull. The basal region of the occipital bone is likely to survive the physical insults than the other parts of skull owing to the abundant soft tissue cover, skull thickness in the region, and its relatively well0protected anatomical position. Thus, there is an increased possibility of recovering this part of skull even in cases of severe trauma, and studies on the occipital bone may provide useful clues in identification of significantly disrupted

Is orbital volume associated with eyeball and visual cortex volume in humans?

Background: In humans orbital volume increases linearly with absolute latitude. Scaling across mammals between visual system components suggests that these larger orbits should translate into larger eyes and visual cortices in high latitude humans. Larger eyes at high latitudes may be required to maintain adequate visual acuity and enhance visual sensitivity under lower light levels.Aim: To test the assumption that orbital volume can accurately index eyeball and visual cortex volumes specifically in humans.Subjects and methods: Structural Magnetic Resonance Imaging (MRI) techniques are employed to measure eye and orbit (n = 88) and brain and visual cortex (n = 99) volumes in living humans. Facial dimensions and foramen magnum area (a proxy for body mass) were also measured.Results: A significant positive linear relationship was found between (i) orbital and eyeball volumes, (ii) eyeball and visual cortex grey matter volumes and (iii) different visual cortical areas, independently of overall brain volume.Conclusion: In humans the components of the visual system scale from orbit to eye to visual cortex volume independently of overall brain size. These findings indicate that orbit volume can index eye and visual cortex volume in humans, suggesting that larger high latitude orbits do translate into larger visual cortices.

The growth of the foramen magnum in Crouzon syndrome

Though the craniovertebral junction is often abnormal in children with Crouzon's syndrome, no study had measured accurately the size of their foramen magnum (FM). We compared the FM size (area, diameters) on computed tomography examination in 21 children with a genetically confirmed Crouzon's syndrome prior to any surgery and in 23 control children without craniofacial abnormalities. We extrapolated the growth pattern in both groups. We found a statistically significant smaller FM area (p=0.0228), FM sagittal diameter (p=0.0287), and FM sagittal posterior diameter (p=0.0023) in children with Crouzon's syndrome. No differences were detected with regard to the transversal diameter. Hydrocephalus in children with Crouzon's syndrome was associated with a small FM area (p=0.05), small sagittal diameter (p=0.023), small sagittal posterior diameter (p=0.0173), and reduced transversal diameter (p=0.03985). No association of the aforementioned findings was found with the position of the cerebellar tonsils or the lambdoid suture functional state (open or fused). Comparable results were observed among the two genetic forms (exon 8 or 10 mutations). Concerning the growth pattern, a first phase of rapid increase and a second phase of slow increase could be recognized in all the measurements in both populations, though with some significant differences. The growth of FM follows a biphasic pattern in both Crouzon's and control children. The sagittal diameter and the global size of the FM are mostly affected in children with Crouzon's syndrome. The small FM, especially its posterior part, is likely to play a key role in the physiopathology of hydrocephalus.