An anthropometric study of relationships between the clival angle and craniofacial measurements in adult human skulls

Skull Base Angle Morphometry in South Indian Population with Review on Terminology

Introduction Basal angle, Boogaard’s angle, and clival angle are frequently used in diagnosing the craniometric angle malformations either on radiography or now more on MRI. But anatomic and clinical studies have used varied terms for these parameters. We aimed to look for these parameters among a normal south Indian adult population to standardize the measurements and their terminology.

Materials and Methods One hundred MRI images (50 males and 50 female) were studied retrospectively. MRI images that were reported as normal by neuroradiologist were taken up for the study. Mean and the standard deviation of males and females were calculated for basal angle, Boogaard’s angle, and clival angle, separately. Unpaired t-test was used to analyze the significant difference (p < 0.05) between the genders. The intraclass coefficient correlation was used to analyze the interobserver variability.

Results The mean value of basal angle in males and females are 113°and 114°, respectively. The mean value of Boogaard’s angle in males and females are 120°and 121°, respectively. The mean value of clival angle in males and females are 157°and 155°, respectively. There was no statistically significant difference (p > 0.05) between males and females in all three angles.

Conclusion Knowledge about the normal angles will be an important tool in understanding the normal and abnormal skull base. Since the type of skull varies in accordance with race, the normal craniometric angle also varies in accordance with race. The present study tried to standardize the parameters of normal skull base angles for appropriate correction of the anomalies and uniform usage of terminology.

Use of Morphometric Mapping to Characterise Symptomatic Chiari-Like Malformation, Secondary Syringomyelia and Associated Brachycephaly in the Cavalier King Charles Spaniel

Objectives

To characterise the symptomatic phenotype of Chiari-like malformation (CM), secondary syringomyelia (SM) and brachycephaly in the Cavalier King Charles Spaniel using morphometric measurements on mid-sagittal Magnetic Resonance images (MRI) of the brain and craniocervical junction.

Methods

This retrospective study, based on a previous quantitative analysis in the Griffon Bruxellois (GB), used 24 measurements taken on 130 T1-weighted MRI of hindbrain and cervical region. Associated brachycephaly was estimated using 26 measurements, including rostral forebrain flattening and olfactory lobe rotation, on 72 T2-weighted MRI of the whole brain. Both study cohorts were divided into three groups; Control, CM pain and SM and their morphometries compared with each other.

Results

Fourteen significant traits were identified in the hindbrain study and nine traits in the whole brain study, six of which were similar to the GB and suggest a common aetiology. The Control cohort had the most elliptical brain (p = 0.010), least olfactory bulb rotation (p = 0.003) and a protective angle (p = 0.004) compared to the other groups. The CM pain cohort had the greatest rostral forebrain flattening (p = 0.007), shortest basioccipital (p = 0.019), but a greater distance between the atlas and basioccipital (p = 0.002) which was protective for SM. The SM cohort had two conformation anomalies depending on the severity of craniocervical junction incongruities; i) the proximity of the dens (p <0.001) ii) increased airorhynchy with a smaller, more ventrally rotated olfactory bulb (p <0.001). Both generated ‘concertina’ flexures of the brain and craniocervical junction.

Conclusion

Morphometric mapping provides a diagnostic tool for quantifying symptomatic CM, secondary SM and their relationship with brachycephaly. It is hypothesized that CM pain is associated with increased brachycephaly and SM can result from different combinations of abnormalities of the forebrain, caudal fossa and craniocervical junction which compromise the neural parenchyma and impede cerebrospinal fluid flow.

Morphometric measurements of the cranium in congenital bilateral blind males and females

Cranium dimensions differ according to racial, geopraphic, ethnic and nutritional factors. This study will shed light on the question: "Is there a difference in the cranial distances measured between congenital bilateral blind people and healthy individuals?" Nine anthropometric measures were performed on the brain MRI midsagittally obtained from male and female congenital bilateral blinds. The anthropometric measures taken included the glabella-opisthocranion, nasion-dorsum sellae, dorsum sellae- opisthocranion, nasion-basion, nasion-opisthion, basion-opisthion, prosthion-basion, basion-vertex and the clival angle. In addition, the supratentorial and infratentorial areas were calculated. Glabella-opisthocranion, nasion-dorsum sellae, nasion-basion, prosthion-basion and clival angle were found to be smaller in the congenital bilateral blind females compared to the healthy group, but these results were not statistically significant. Whereas, other measures out of the basion-opisthion were found to be smaller in the congenital bilateral blind males than in the healthy subjects. Of these results, the distance between glabella-opisthocranion, nasion-dorsum sellae and nasion-basion was significantly smaller compared to the measurements taken from the healthy male group. The infratentorial area was significantly smaller in congenital blind male subjects and the supratentorial area was significantly larger in congenital blind female subjects. This study has revealed that the cranium dimensions of congenital blind people are to different from normal individuals. The most significant difference was in the distance of the nasion-dorsum sellae. The region anterior to the basion and dorsum sellae was prominently smaller. The infratentorial area was significantly smaller in congenital blind male subjects and the supratentorial area was significantly larger in congenital blind female subjects.

Sagittal craniofacial growth evaluated on children dry skulls using V2 and V3 canal openings as references

The purpose of this study was to investigate the relationship between standard cephalometric landmarks and lines and those using ovale, rotundum, greater palatine and infra-orbital foramina as references. Thirty-four children dry skulls, 19 males and 15 females aged 0-6 years, were examined by computed tomography scanning. The classical cephalometric dimensions of skull base were measured from middle sagittal plane crossing over basion, nasion and sella turcica. Those of hard palate (maxilla and palatine bone) were measured from axial plane intersecting posterior nasal spine and anterior nasal spine. The dimensions between ovale and rotundum foramina, rotundum and infra-orbital foramina, greater palatine and infra-orbital foramina were determined by using constructed tomographic planes enclosing these different foramina. Biostatistical analysis using partial correlations showed that the linear variables with nerve canal openings as references are strongly related to length of both the skull base and of the hard palate. The results highlight the importance of the nerve canal openings of skull base and bone facial components in normal or pathologic craniofacial growth investigations.