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Skull volume in infants. Methodology, normal values, and application.

Skull volume was determined from measurements on roentgenograms in 53 infants with normally shaped skulls. A positive relationship existed between occipitofrontal circumference (OFC) and skull volume. Formulas related OFC to skull volume for each sex at different age intervals were computed. With these formulas and published data, percentile ranks for skull volume were calculated for age and sex. In seven infants with abnormally shaped skulls, the relationship between OFC and skull volume differed from infants with normally shaped skulls. The OFC was not a reliable indicator of cranial volume in infants with abnormally shaped skulls. Serial determination of skull volume is proposed as a method of following the brain growth of these infants.

Brain↗

Does nasotracheal intubation increase complications in patients with skull base fractures?

STUDY OBJECTIVES: To determine if the complications associated with skull base fractures are increased when nasotracheal intubation is performed in the field. DESIGN: Retrospective, case-control study over a five-year period. SETTING: A helicopter service returning to a Level I trauma center. TYPE OF PARTICIPANTS: All injured patients treated in the field who had either radiographic or clinical evidence of skull base fractures in whom nasotracheal intubation was attempted (38) compared with all patients with skull base fractures in whom nasotracheal intubation was not attempted (48) and a convenience sample of patients without skull base fractures in whom nasotracheal intubation was attempted (45). Patients with obvious midface motion on initial examination were excluded. Complications of skull base fractures were categorized as cerebral spinal fluid leak of longer than 24 hours and/or meningitis, cranial nerve injury, diabetes insipidus, and intracranial placement of the endotracheal tube. INTERVENTIONS: Blind nasotracheal intubation was performed by experienced flight nurses. RESULTS: There were no patients in whom an endotracheal tube was placed intracranially. There was no significant difference in complication rate between the two groups with skull base fractures (with nasotracheal intubation, 24%; 95% confidence interval, 11% to 40%; without nasotracheal intubation, 25%; 95% confidence interval, 14% to 40%). The group without skull base fracture had none of the complications usually associated with skull base fractures. CONCLUSION: Patients with skull base fracture have a significant complication rate (25%). The complications associated with skull base fractures are not markedly increased by attempts at nasotracheal intubation in the field.

Adult↗

Correlation of ultrasound phase with physical skull properties.

Noninvasive treatment of brain disorders using focused ultrasound (US) requires a reliable model for predicting the distortion of the field due to the skull using physical parameters obtained in vivo. Previous studies indicate that control of US phase alone is sufficient for producing a focus through the skull using a phased US array. The present study concentrates on identifying methods to estimate phase distortion. This will be critical for the future clinical use of noninvasive brain therapy. Ten ex vivo human calvaria were examined. Each sample was imaged in water using computerized tomography (CT). The information was used to determine the inner and outer skull surfaces, thickness as a function of position, and internal structure. Phase measurement over a series of points was obtained by placing a skull fragment between a transducer and a receiver with the skull normal to the transducer. Correlation was found between the skull thickness and the US phase shift. A linear fit of the data follows that predicted by a homogeneous skull when average speed of sound 2650 m/s was used. Large variance (SD = 60 degrees, mean = 50 degrees ) indicates the additional role of internal bone speed and density fluctuations. In an attempt to reduce the variance, the skull was first studied as a three-layer structure. Next, density-dependent bone speed fluctuation was introduced to both the single-layer and three-layer models. It was determined that adjustment of the mean propagation speeds using density improves the overall phase prediction. Results demonstrate that it is possible to use thickness and density information from CT images to predict the US phase distortion induced by the skull accurately enough for therapeutic aberration correction. In addition, the measurements provide coefficients for phase dependence on skull thickness and density that can be used in clinical treatments.

Brain Diseases↗

Post-natal development in the linear and tric morphometrics of the camelidae skull.

The craniometric measurements in addition to the skull, cranial and facial indices undertaken in the immature and mature male Camelus dromedarius of the Malha phenotype (black) were: the skull length (35.99 cm), maximum width of neurocranium (11.33 cm), cranial length (15.45 cm), maximum zygomatic width (14.81 cm), viscerocranial length (20.55 cm), skull index (41.13), cranial index (73.70), facial index (72.31), cranial volume (231.73 ml) and skull weight (795.70 g) were measured in the immature camels. In the mature camels, the skulls gave the following measurements: the skull length (50.53 cm), maximum width of neurocranium (15.96 cm), cranial length (21.93 cm), maximum zygomatic width (22.75 cm), viscerocranial length (28.60 cm), skull index (45.06), cranial index (72.99), facial index (79.83), cranial volume (310.80 ml) and skull weight (2598.31 g). The results of a total of 30 skulls of immature and mature Malha camel revealed that all the measurements increased with age whereas the cranial index was the only parameter for which a decreased value was recorded. The anterior basicranial angle averaged about 203 degrees in the immature animal to increase to an insignificant value of 204 degrees in the mature camel skull. Similarly, the posterior basicranial angle did not exhibit a significant difference between the immature and mature values, which ranged between 110 and112 degrees,respectively.

Age Factors↗

The correlation between skull fractures and intracranial lesions due to traffic accidents.

In this study, it was aimed to investigate the relationship between skull fractures and intracranial lesions following head injury. For this purpose, 500 cases, which were referred to the Third Committee of Council of Forensic Medicine in Istanbul due to traffic accidents by the courts of laws between 1998 and 2000, were examined retrospectively. They were categorized in 3 groups based on findings of their cranium x-rays and brain tomographies. 1- The cases who have fractures in skull bones with brain lesions 2- The cases who have fractures in skull bones with no brain lesions 3- The cases who have brain lesions with no skull fractures. They were examined in detail according to age, sex, localization of skull fractures and brain lesions, and if surgery was applied or not. Of the cases, 152 (30.4%) had only linear fractures, 69 (13.8%) had depressed fractures, 92 (18.4%) had linear fractures plus intracranial lesions, 49 (9.8%) had depressed fractures plus intracranial lesions and 138 (27.6%) had only intracranial lesions. The rate of intracranial lesion among the cases with the skull fracture was 38.9% (141/362), while the rate of skull fracture among the cases with the intracranial lesion was 50.3% (141/279) (P < 0.001). Male to female ratios were 2.4/1 for linear fractures, 5.2/1 for depressed fractures, and 3.5/1 for intracranial lesions. Linear fractures were more frequent among females whereas depressed fractures were often among males (chi2: 9.68, df: 4, p: 0.046). The mean age was 26.3. The rate of depressed fractures was higher the age groups of 0-30 years. (chi2: 16.28, df: 4, p: 0.003). Depressed fractures in the regions of frontal and parietal and, linear fracture in the regions of temporal and occipital were found at higher rates (P < 0.001). In conclusion, we reviewed skull fractures and/or intracranial lesions due to traffic accidents, and found depressed fractures to be more common among males whereas linear fractures to be more common among females and young males. In the male, the skull architecture is thicker and stronger than females and young males. We can state that presence of skull fractures lowers the incidence of intracranial lesions by lowering the intracranial pressure.

Accidents, Traffic↗

Analysis of the sexual dimorphism in the basioccipital portion of the dog's skull.

Sexual differences in the basioccipital portion of the skull of dogs have been described and an index is presented which reliably predicts the sex of the skull. 92 dolichocephalic skull (44 male, 48 female) from mongrel dogs were used. In the basioccipital region of the male skulls, a triangular area, which extends from the basion to a line joining the medialmost points of the two jugular foramina, appears narrow and elevated. The pharyngeal tubercle is also prominent. In female skulls the rostral angle of this triangle is wider and the triangular area seems smoother and flat. The anterior half of the female basioccipital portion is wider and smoother than in the male skull. In order to quantify the observed differences, four indices were calculated. All of the indices were statistically significant. However, only index IV could be reliably used in predicting the sex of an unknown skull: (formula: see text) was derived from breadth IV (distance between the two temporo-occipital fissures at their lateralmost points) and length II (distance between the basion and a line drawn between the two medialmost points of the jugular foramina in the midline). Values of less than 123 for male and greater than 136 for female placed the skulls in their proper sex group. Skulls that had intermediate values could be placed in correct sex grouping only in conjunction with strong observational criteria. It is suggested that in absence of such strong observational criteria these skulls may belong to immature or castrate animals.

Animals↗

Macroscopic and roentgenographic anatomy of the skull of the ferret (Mustela putorius furo).

Normal macroscopic and roentgenographic features of the skull of the ferret (Mustela putorius furo) were examined and described. Data were based on a sample of 100 (50 male and 50 female) adult ferrets of known body weight and age. The skull was described macroscopically according to six standard views, i.e. dorsal, lateral, ventral, caudal, cranial and midsagittal. The mandible was described separately. The roentgenographic characteristics of the ferret skull were demonstrated only in lateral and dorsoventral projections. Furthermore, the skull length and width as well as the minimum frontal width were measured, and skull indices were derived from relevant measurements. Sexual dimorphism was examined both morphologically and craniometrically. Besides the common features of a carnivore skull, the ferret skull is relatively elongated and flat with a short facial region. The skulls of adult male ferrets are about 17% longer and 22% wider than those of the females. Significant sexual dimorphism also exists regarding certain skull indices. The general features and some dimensional parameters of the adult ferret skull support the contention that the ferret would be an interesting and workable alternative animal model in craniofacial research.

Animals↗

Tumors of the skull base in children and adolescents.

OBJECT: Published data obtained in children with tumors of the skull base are sparse. In the majority of the available reports, the authors focus on the technical application of skull base approaches, but they contribute a paucity of information on the management of specific tumors, especially malignant skull base lesions. The purposes of this report are to increase the collective experience with the treatment of these tumors and to identify successful management paradigms. METHODS: The authors retrospectively reviewed the clinical records, pathological reports, and diagnostic images obtained in 24 children (< or = 19 years of age) with tumors arising from the cranial base in whom resection was part of their management between 1992 and 2002. Surgery-related complications and outcomes were analyzed with regard to tumor type and surgical approach. The median age of the group was 14 years. Tumors involved the anterior skull base in eight (33%), the middle skull base in 10 (42%), both the anterior and middle skull base in four (17%), and the posterior skull base in two patients (8%). Benign lesions were discovered in 11 patients (46%) and malignant neoplasms in 13 (54%). The tumors were most commonly of mesenchymal origin (21 [87.5%] of 24 tumors). Thirty surgical procedures were performed using a number of skull base approaches. A gross-total resection was achieved in 23 procedures (77%) and a subtotal resection in five (17%); a biopsy procedure was performed in one case; and the disease process could not be accessed in one case. One patient died in the perioperative period. Minor complications (Karnofsky Performance Scale score > or = 90, no prolongation of hospital stay, and no further surgery needed) occurred following 10 (33%) of the 30 surgical procedures. These affected 10 (42%) of the 24 patients and resulted in persistent or prolonged deficits in only five patients (21%). In nine patients (38%) the tumor recurred after a mean duration of 23 months. CONCLUSIONS: Skull base tumors in children affect mainly the anterior and middle cranial fossa. Sarcomas account for the majority of malignant tumors. Treatment of skull base tumors in children and adolescents needs to be tailored to patient age, tumor location, and tumor type.

Adolescent↗

Phylogenetic and environmental components of morphological variation: skull, mandible, and molar shape in marmots (Marmota, Rodentia).

The phenotype is a product of its phylogenetic history and its recent adaptation to local environments, but the relative importance of the two factors is controversial. We assessed the effects of diet, habitat, elevation, temperature, precipitation, body size, and mtDNA genetic divergence on shape variation in skulls, mandibles, and molars, structures that differ in their genetic and functional control. We asked whether these structures have adapted to environment to the same extent and whether they retain the same amount of phylogenetic signal. We studied these traits in intra- and interspecific populations of Eurasian marmots whose last common ancestor lived 2-5 million years ago. Path Analysis revealed that body size explained 10% of variation in skulls, 7% in mandibles, and 15% in molars. Local vegetation explained 7% of variation in skulls, 11% in mandibles, and 12% in molars. Dietary category explained 25% of variation in skulls, 11% in mandibles, and 9% in molars. Cyt b mtDNA divergence (phylogeny) explained 15% of variation in skulls, 7% in mandibles, and 5% in molars. Despite the percentages of phylogenetic variance, maximum-likelihood trees based on molar and skull shape recovered most phylogenetic groupings correctly, but mandible shape did not. The good performance of molars and skulls was probably due to different factors. Skulls are genetically and functionally more complicated than teeth, and they had more mathematically independent components of variation (5-6-in skulls compared to 3-in molars). The high proportion of diet-related variance was not enough to mask the phylogenetic signal. Molars had fewer independent components, but they also have less ecophenotypic variation and evolve more slowly, giving each component a proportionally stronger phylogenetic signal. Molars require larger samples for each operational taxonomic unit than the other structures because the proportion of within-taxon to between-taxon variation was higher. Good phylogenetic signal in quantitative skeletal morphology is likely to be found only when the taxa have a common ancestry no older than hundreds of thousands or millions of years (1% to 10% mtDNA divergence)--under these conditions skulls and molars provide stronger signal than mandibles.

Animals↗

Anatomo-radiological evaluation of lateral approaches to the skull base.

Our objective is to correlate the anatomical exposure provided by complex skull base approaches to the lateral skull base with their CT and MRI scans counterparts and to introduce a modular concept emphasizing the derivation of complex skull base approaches from simpler ones.We executed 10 lateral approaches to the skull base in 20 embalmed cadaveric heads (40 sides). Each approach was executed a minimum of three times on each specimen. These approaches were the pterional and its modifications, the subtemporal and its modifications, and the suboccipital and its modifications. We correlated the approaches and the areas of the skull base exposed by scanning the surgical cavity filled with material imageable by CT and MRI and throughly surveying the operative field.Visualization of the area of the skull base exposed was excellent using our CT-MRI imageable cadaveric preparation. The topographic areas of the skull base exposed correlated well with their radiological counterparts.The areas of the skull base exposed by each of the complex surgical approaches to the skull base were clearly delineated by using our anatomo-radiological correlation. Complex approaches to the skull base are formed by simple neurosurgical approaches (building blocks) to which different modules are added.

Journal Article↗

Sexing the human skull through the mastoid process.

OBJECTIVE: The purpose of this study was to evaluate the significance for sex determination of the measurement of the area formed by the xerographic projection of 3 craniometric points related to the mastoid process: the porion, asterion, and mastoidale points. METHOD: Sixty skulls, 30 male and 30 female, were analyzed. A xerographic copy of each side of the skull was obtained. On each xerographic copy, the craniometric points were marked to demarcate a triangle. The area (mm ) of the demarcated triangle for each side of the skull (right (D) and left (E) sides) was determined, and the total value of these measures (T) was calculated. RESULTS: Concerning the right area of the male and female skulls, 60% of the values overlapped; for the left area, 51.67% overlapped, and for the total area, 36.67% overlapped. The analysis of the differences between the sexes in the areas studied was significant for the 3 areas. Regarding the total area, which is the preferred measurement because of the asymmetry between the sides of the skull, the value of the mean was 1505.32 mm for male skulls, which was greater than the maximum value obtained in the female skulls. The value of the mean for female skulls was 1221.24 mm , less than the minimum value obtained for the male skulls. CONCLUSIONS: This study demonstrates a significant result in the 3 studied areas, (D), (E), and (T). The total area values show less overlapping of values between the sexes, and therefore can be used for sexing human skulls. For the population studied, values of the total area that were greater than or equal to 1447.40 mm belonged to male crania (95% confidence). Values for this area that were less than or equal to 1260.36 mm belonged to female crania (95% confidence).

Cephalometry↗

Evaluation of orbital stress dissipation in pediatric and adult skulls using electronic speckle pattern interferometry.

OBJECTIVES: To measure and quantitatively compare the degree of force dissipation in pediatric and adult skulls subjected to similar dynamic forces. DESIGN: An anatomical study using electronic speckle pattern interferometry, which allows generation of displacement vectors after application of a force. SUBJECTS: Five human skulls (3 pediatric and 2 adult). INTERVENTION: Each skull was subjected to a reproducible and quantifiable force created by a steel ball pendulum striking a precise periorbital focus: (1) infraorbital foramen, (2) supraorbital notch, (3) malar eminence, and (4) nasofrontal suture. Electronic speckle pattern interferometry was used to construct interferogram fringe patterns to determine skull regions with the greatest degree of displacement. RESULTS: Interferogram analysis revealed that the adult skull has a tendency to dissipate force with minimal resultant displacement. In contrast, the pediatric skulls demonstrated greater displacements (ie, increased fringe density) at the same periorbital foci. CONCLUSIONS: The pediatric skull dissipates periorbital stress differently than the adult skull, as illustrated by quantitative interferogram analysis. This finding parallels clinical data that demonstrate a varying pattern of fractures in pediatric and adult skulls related to craniofacial development.

Adult↗

A surgical method for treating anterior skull base injuries.

Skull base surgery was performed on 18 patients with anterior skull base injuries. The operative technique consisted of opening the operative field in the anterior skull base via a coronal incision and a frontal craniotomy, debridement of the anterior skull base including the injured dura mater, performing drainage from the anterior skull base to the nasal cavity by ethmoidectomy, and reconstructing the resulting dural and anterior skull base defect using bilateral temporal musculo-pericranial flaps and a bone graft. Seventeen of the 18 patients recovered without any complications, although epidural abscesses in the anterior skull base had been present in four patients at the time of the operation. Only one patient developed an epidural abscess in the anterior skull base after the operation. None of the patients developed any other complications including meningitis, recurrent liquorrhoea or cerebral herniation. Satisfactory aesthetic results were achieved in 16 of the 18 patients. In one patient, uneven deformity of the forehead, which was caused by the partial sequestration of the frontal bone due to postoperative infection, was observed. In another patient, a depressed deformity of the forehead, which was caused by the partial loss of the frontalis muscle following the use of the frontal musculo-pericranial flap instead of a temporal musculo-pericranial flap, was observed. Anterior skull base reconstruction using bilateral temporal musculo-pericranial flaps provides excellent results in terms of patient recovery and aesthetics.

Adolescent↗

[CT evaluation of the primary extracranial neoplastic diseases eroding the central skull base].

OBJECTIVE: To evaluate the central skull base erosion caused by primary extracranial mass lesions with CT. METHODS: Forty-nine patients (33 males and 16 females; mean, 40.2 years) suffered from the primary extracranial neoplastic diseases with middle skull base involvement were divided into two groups: group I (10 cases), primary osseous lesions of the central skull base and group II (39 cases), primary maxillofacial neoplasms. All lesions were confirmed histopathologically by surgery and biopsy. RESULTS: Four invasion patterns of the central skull base were identified on CT: I. resorption of the cortical bone (30 cases), including outer cortical margin destruction in 16 cases (group II lesions) and both inner and outer laminae resorption in 14 cases (4 group I lesions and 10 groups II lesions). II. ossification and thickening of the skull base (4 group I cases, all were fibrous dysplasia) III. erosive enlargement of the ovale and rotundam foramina (9 group II cases). IV. combined sclerosis and resorption of the skull base (6 cases, 2 group I lesions and 4 group II lesions). Involvement of the intracranial structures embraced the cavernous sinus (n = 12; group II lesions), temporal lobe (n = 11; 5 group I lesions and 6 group II lesions), and pituitary (n = 2, group II lesions). CT demonstrated the following central skull base structures were eroded: greater wing of sphenoid bone (n = 34), sphenoid body (n = 22), sphenoid process (n = 23), petrous bone (n = 15), and articular fossa of the temporal bone (n = 8). CONCLUSION: Osseous lesions originating from the central skull base have various CT manifestations. The cortical resorption of the central skull base may be regarded as a main pattern of bone erosion caused by primary maxillofacial neoplasms, and most of them have lesions involve the greater wing of sphenoid bone through the deeper maxillofacial spaces, such as the infratemporal, pterygopalatine and parapharyngeal spaces.

Adolescent↗

Evaluation of guidelines for skull radiography in head injury.

The benefits of utilisation of guidelines for radiographic skull examination of head injured patients were studied in one hundred and eleven patients. The causes of head injury were road traffic accidents (RTA) 87.4%, fall and assault 4.5% each, collapsed wall 1.8%, gunshot injury and industrial accident 0.9% each. RTA resulted predominantly from burst tyre 34%, vehicle pedestrian accidents 23.7% and vehicle collision 18.6%. Compliance with the use of the guidelines was 48%. Radiographic skull examination was carried out in 22 patients (20% of study population) and the positive yield for skull fracture was 32% (7/22 of all radiographs). At discharge, 14 of those who had radiographic examination (n=20) recovered without neurological complications while 39 among those not examined (n=58) similarly recovered, p=0.96. Among those who had skull radiography, neurological deficit occurred in 6 that had skull fractures (n=7) and in 5 of those without skull fractures (n=13), p=0.07. It was concluded that radiographic skull examination based on selective guidelines increases the yield of skull fractures and reduces unnecessary examinations, thereby saving costs. Skull radiography may not be predictive of neurological outcome of treatment. Cranial computed tomography (CT) should be obtained if available and clinically indicated.

Adolescent↗

The value of skull radiography in patients with head trauma.

This study assesses the value of skull X-ray after a skull fracture for predicting intracranial hematoma. Patients with a skull injury were divided into three risk groups, based on the history and examination findings. The records of 1218 patients were studied. In the risk group, the existence of a skull fracture and the development of intracranial hematoma were determined. Not a single hematoma was found in the low-risk group. Hence, skull radiography had no significance in this group. In the moderate-risk group two patients had an intracranial hematoma; one patient had a skull fracture. Negative skull radiography therefore did not fully exclude intracranial complications. There were many patients with an intracranial hematoma in the high-risk group, in the presence or not of a skull fracture. CT imaging is the best method for obtaining the diagnosis of intracranial hematoma in this group. In conclusion, plain skull X-rays are of little value in patients with acute head trauma.

Adult↗

Bilaterally symmetric Fourier approximations of the skull outlines of temnospondyl amphibians and their bearing on shape comparison.

Present work illustrates a scheme of quantitative description of the shape of the skull outlines of temnospondyl amphibians using bilaterally symmetric closed Fourier curves. Some special points have been identified on the Fourier fits of the skull outlines, which are the local maxima, or minima of the distances from the centroid of the points at the skull outline. These points denotes break in curvature of the outline and their positions can be compared to differentiate the skull shapes. The ratios of arc-lengths of the posterior and lateral outline of 58 temnospondyl skulls have been plotted to generate a triaguarity series of the skulls. This series grades different families, some of their genera and species as well as some individuals according to their posterior and lateral skull length ratios. This model while comparing different taxa, takes into account the entire arc-length of the outline of the temnospondyl skulls, and does not depend on few geometric or biological points used by earlier workers for comparing skull shapes.

Amphibians↗

Skull vault growth in craniosynostosis.

BACKGROUND: Since its first description by Virchow, the principle of abnormal skull growth due to restriction of skull growth at the fused sutures, and the realisation by Moss that the sutures at the skull base are equally affected, have been the main intellectual driving forces behind the majority of cranial expansion procedures performed currently in children with craniosynostosis. CURRENT OBSERVATIONS: Despite original impressions that craniosynostosis leads to craniostenosis, many studies have demonstrated that in the majority of patients with craniosynostosis there is normal skull volume in those over the age of 6 months. In Apert syndrome, skull volume is invariably larger than normal. Some studies have shown that intracranial pressure is independent of intracranial volume, and can exist in the presence of normal volume, or indeed after cranial expansion. These observations imply that cranial expansion procedures create a state of artificially increased skull volume, in the quest to improve appearance and function. FUTURE ADVANCES: This creates a new angle of view through which skull growth abnormalities are seen. It is becoming clearer that in most patients with craniosynostosis, there is regional imbalance of skull growth, which co-exists with a variety of other equally important factors, such as genetic defects, raised intracranial pressure, venous hypertension, and other brain parenchymal anomalies such as hindbrain hernia or hydrocephalus. It is becoming increasingly obvious that the type of surgical treatment currently practised in most cases is conceptually incorrect. Recent modifications such as the use of springs or distraction do not escape from the underlying philosophy of cranial expansion. With that in mind, it is hoped that advances in the fields of genetics and molecular biology will provide treatments for the cause of craniosynostosis rather than the symptomatic relief that surgery offers currently. CONCLUSION: Until then, there is a need to develop better ways of quantifying regional abnormalities of skull growth.

Cranial Sutures↗