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At least 487 records · Page 27Linked to original sources
PubMed1998

Registering coronal histological 2-D sections of a rat brain with coronal sections of a 3-D brain atlas using geometric curve invariants and B-spline representation.

A new approach is proposed for registering a set of histological coronal two-dimensional images of a rat brain sectional material with coronal sections of a three-dimensional brain atlas, an intrinsic step and a significant challenge to current efforts in brain mapping and multimodal fusion of experimental data. The alignment problem is based on matching external contours of the brain sections, and operates in the presence of tissue distortion and tears which are routinely encountered, and possible scale, rotation, and shear changes (the affine and weak perspective groups). It is based on a novel set of local absolute affine invariants derived from the set of ordered inflection points on the external contour represented by a cubic B-spline curve. The inflection points are local intrinsic geometric features, which are preserved under both the affine and the weak perspective transformations. The invariants are constructed from the sequence of area patches bounded by the contour and the line connecting two consecutive inflection points, and hence do make direct use of the area (volume) invariance property associated with the affine transformation. These local absolute invariants are very well suited to handle the tissue distortion and tears (occlusion problem).

Algorithms↗
PubMed2000

Assessment of primary hip osteoarthritis: comparison of radiographic methods using colon radiographs.

OBJECTIVE: To compare the reliability of quantitative measurement of minimum hip joint space with a qualitative global assessment of radiological features for estimating the prevalence of primary osteoarthritis (OA) of the hip in colon radiographs. METHODS: All colon radiographs from patients aged 35 or older, taken at three different radiographic departments in Iceland during the years 1990-96, were examined. A total of 3002 hips in 638 men and 863 women were analysed. Intraobserver and interobserver reliability was assessed by measuring 147 randomly selected radiographs (294 hips) twice by the same observer, and 87 and 98 randomly selected radiographs (174 and 196 hips) by two additional independent observers. Minimum hip joint space was measured with a millimetre ruler, and global assessment of radiological features by a published atlas. RESULTS: With a minimum joint space of 2.5 mm or less as definition for OA, 212 hips were defined as having OA. When the global Kellgren and Lawrence assessment with grade 2 (definite narrowing in the presence of definite osteophytes) or higher as definition for OA was used, 202 hips showed OA. However, only 166 hips were diagnosed as OA with both systems. With 2.0 or 3.0 mm minimum joint space as cut off point, the difference between the two methods increased. Both intrarater and interrater reliability was significantly higher with joint space measurement than with global assessment. CONCLUSIONS: Overall prevalence of radiological OA was similar with the two methods. However, the quantitative measurement of minimum hip joint space had a better within-observer and between-observer reliability than qualitative global assessment of radiographic features of hip OA. It is thus suggested that minimum joint space measurement is a preferable method in epidemiological studies of radiological hip OA.

Adult↗
PubMedDate not supplied

Digital radiographic measurement of the atlantodental interval in children.

The atlantodental interval (ADI) is assessed after trauma to the head and neck region to determine whether the transverse ligament of the atlas is intact. Atlantodental interval measurement from conventional screen-film radiographs is characterized by the need for magnification correction and by low reliability. Assessment of normal ADI values using digital radiography with computer-assisted measurement has not been reported. We compared with published values the digital radiographic measurements of ADI in children, examined the reliability of measurements, and examined the interaction between age, sex and ADI. Computer-assisted digital measurements of ADI in 101 children, aged 1 to 12 years, were obtained from lateral supine head-neutral radiographs. We found intraobserver reliability of 0.72 and 0.85, interobserver reliability of 0.50, a maximum ADI value of 3.5 mm, no effect of sex and age, and weak evidence for an interaction between sex and age. Computer-assisted digital ADI measurement provides higher intraobserver reliability than what has previously been reported, and interobserver reliability and a maximum ADI value similar to that found in the literature.

Axis, Cervical Vertebra↗
PubMed1988

Auditory brain map, effects of age.

Brain maps of late auditory evoked cortical potentials were obtained with the Brain Atlas III system in school-aged children and adults. All subjects were judged as neurologically normal, right-handed, and having normal hearing. The stimulus was a 100 ms burst of 500 Hz pure tone at 75 dB HL presented separately to the left and right ear. The results showed a frontoparietal maximum of negative activity corresponding to N1 and designated as the focus of N1 (FN1). FN1 had latencies of 108 ms (left stimulation (stim] and 113 ms (right stim) and amplitudes of -6.0 microV (left stim) and -4.8 microV (right stim) in children and a latency of 90 ms and an amplitude of -6.5 microV in adults. Among the children, more had ipsilateral than contralateral FN1, usually on the right side. The distance between the centers of gravity of FN1s obtained on stimulation of the two ears was significantly smaller in the maps of children than adults (p less than 0.01). The present findings indicated that the topography of the electrical activity changes during adolescence.

Adult↗
PubMed2026

Crucial role of telomere maintenance-related genes in survival prediction and subtype identification in colorectal cancer.

BACKGROUND: Telomere maintenance-related genes (TMRGs) are implicated in Colorectal cancer (CRC) development, but their prognostic value and clinical relevance remain insufficiently explored. This study aims to develop a TMRG-based prognostic model and elucidate its clinical utility in CRC management. METHODS: The Cancer Genome Atlas database was utilized to download RNA-seq data from 638 CRC and 51 control samples. Differential expressed genes were screened and intersected with 2086 TMRGs, resulting in the identification of 976 TMRGs. Through univariate and multivariate Cox regression analysis, a prognostic model comprising three telomere maintenance-related biomarkers (PDE1B, TFAP2B, and HSPA1A) was developed and validated using an external dataset. By integrating the model risk score with clinical features, a nomogram was constructed to predict the survival outcomes of CRC patients. Additionally, an in-depth investigation of the immuno-infiltration, functional variation and drug sensitivity analysis were performed in two risk subgroups defined by the prognostic model. Finally, the functional significance of PDE1B in CRC cell lines was investigated through MTT assays, cell colony formation assays, transwell assays and flow cytometry. RESULTS: A total of 976 DE-TMRGs were enriched in telomere/DNA replication pathways. A three-gene signature (PDE1B, TFAP2B, and HSPA1A) stratified patients into high- and low-risk groups with divergent survival (AUC >0.60, validated externally). High-risk patients had advanced N/M stages, elevated M0/M2 macrophages, reduced CD4+ memory T cells, and upregulated immune checkpoints. Nomogram integrating risk score, age, and N/M stage accurately predicted 1-/3-/5-year survival. Low-risk patients showed greater 5-fluorouracil sensitivity. PDE1B expression was significantly reduced in CRC tissues and correlated with advanced stages. Functional assays confirmed PDE1B overexpression suppressed proliferation, migration, invasion, and induced apoptosis in CRC cells. CONCLUSION: This study identifies a moderately predictive telomere maintenance-related gene signature as an independent prognostic predictor in CRC. The risk stratification model effectively discriminates patients with distinct survival patterns, tumor microenvironments, and therapeutic responses, while the integrated nomogram offers additional reference information for survival analysis, albeit with only moderate predictive accuracy. These findings indicate telomere maintenance-related gene signature could serve as a preliminary auxiliary risk stratification tool for postoperative CRC patients, PDE1B may also serve as a potential epithelial tumor-suppressor target for future preclinical studies.

PDE1B↗
PubMed2006

Functional connectivity between trigeminal and occipital nerves revealed by occipital nerve blockade and nociceptive blink reflexes.

Headache syndromes often suggest occipital and neck involvement, although it is still unknown to what extent branches of segment C1-C3 contribute actively to primary headache. Pain within the occipital area may be referred to the trigeminal territory. However, a modulation of trigeminal transmission by affecting cervical input in humans has not been elucidated so far. A convergence of cervical and trigeminal input at the level of the caudal part of the trigeminal nucleus in the brainstem has been suggested due to anatomical and neurophysiological studies in animals. We examined the R2 components of the nociceptive blink reflex responses in 15 healthy subjects before and after unilateral nerve blockade of the greater occipital nerve with 5 ml prilocain (1%). R2 response areas (AUC) decreased and the R2 latencies increased significantly after the nerve blockade only on the side of injection. AUC and latencies on the non-injection side remained stable. Thresholds for sensory or pain perception did not differ significantly between the repeated measurements on both sides. Our findings extend previous results related to anatomical and functional convergence of trigeminal and cervical afferent pathways in animals and suggest that the modulation of this pathway is of potential benefit in primary headache disorders.

Adult↗
PubMed2026

Stratifying lung adenocarcinoma: a novel prognostic model based on mitochondrial outer membrane permeabilization activity.

UNLABELLED: Mitochondrial outer membrane permeabilization (MOMP) is a core apoptotic regulatory event that dictates mitochondrial integrity, where full activation drives cell death and sublethal dysregulation contributes to tumor genomic instability. We used the Cancer Genome Atlas lung adenocarcinoma cohort (TCGA-LUAD) as the training cohort and the Gene Expression Omnibus dataset GSE42127 as the validation cohort to identify prognostic genes related to MOMP activity in lung adenocarcinoma (LUAD) and to evaluate their potential biological significance. By intersecting MOMP-related genes with differentially expressed genes, combined with survival analysis, Mendelian randomization analysis, and 101 machine-learning algorithm combinations, seven prognostic genes, namely BIRC5, PSMD11, TNFRSF13C, YWHAZ, YWHAG, CYCS, and LTB, were identified. Next, an optimal prognostic model was constructed based on the gradient boosting machine (GBM) algorithm. Based on the risk score, LUAD patients were stratified into high- and low-risk groups, and patients in the high-risk group exhibited poorer overall survival in both the training and validation cohorts. Furthermore, a nomogram integrating the risk score and clinicopathological factors was developed and showed favorable predictive performance for 1-, 3-, and 5-year survival. Meanwhile, functional and immune analyses revealed that the high-risk group was enriched in DNA replication-related pathways and demonstrated a higher tumor mutation burden (TMB). Correlation analysis indicated that TNFRSF13C was positively correlated with activated B cells, whereas BIRC5 was negatively correlated with eosinophils, suggesting that MOMP-related genes might be involved in remodeling the immune microenvironment of LUAD. Drug sensitivity analysis showed differences in predicted half-maximal inhibitory concentration (IC50) values between the risk groups, suggesting the potential value of this model in assisting therapeutic stratification. Single-cell RNA sequencing (scRNA-seq) further identified T lymphocytes as a key cell type, with numerous prognostic genes exhibiting differential expression in T cells or dynamic changes during differentiation. We suggest that the MOMP-related signature established in this study may provide a reference for prognostic stratification in LUAD and offers candidate prognostic genes for subsequent experimental and clinical validation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s13205-026-05058-6.

Lung adenocarcinoma↗
PubMed1999

[The canons of morphotypes in adults. Anatomic atlas and database].

Orthopedic surgery for subjects of small stature, (between 130 cm and 160 cm), after the end of the normal growth cycle, requires a definition of the individual's morphotype, according to the standard canons. There exists a "classic canon", from Mediterranean culture, which divides the human body, from the waist, into two unequal parts (in the longitudinal dimension), which can vary from excessive shortness to excessive height. These proportions are strongly hereditary. In the transversal sense, there exists also measurements which can widely vary. These, are also strongly hereditary. Thus, defining five measurements: Stature. Height from the waist to the ground. Height from the waist to the top-head. Width of the shoulders. Width of the pelvis. From these five measurements, in the longitudinal and transversal dimensions, we obtain the well defined outlines of the subject's morphotype as well as, all other variations of this morphotype. Because there are separate variations of the transversal and longitudinal canons. A canon is specific to a group or a population. There are an infinite number of canons on this earth. Before starting limb lengthening surgery, it's necessary to define the morphotype (canon) of the subject. The harmony or dysharmony of his body proportions. As well as determine, at which point of lengthening, will the patient realise a true benefit for this difficult surgery.

Adult↗
PubMedDate not supplied

Automated CT segmentation and analysis for acute middle cerebral artery stroke.

BACKGROUND AND PURPOSE: The quantitative nature of CT should make it amenable to semiautomated analysis using modern neuroimaging methods. The purpose of this study was to begin to develop automated methods of analysis of CT scans to identify putative hypodensity within the lentiform nucleus and insula in patients with acute middle cerebral artery stroke. METHODS: Thirty-five CT scans were retrospectively selected from our CT archive (scans of 20 normal control participants and 15 patients presenting with acute middle cerebral artery stroke symptoms). The DICOM data for each participant were interpolated to a single volume, scalp stripped, normalized to a standard atlas, and segmented into anatomic regions. Voxel densities in the lentiform nucleus and insula were compared with the contralateral side at P <.01 using the Wilcoxon two-sample rank sum statistic, corrected for spatial autocorrelation. RESULTS: The quality of the registration for the anatomic regions was excellent. The control group had two false-positive results. The patient group had two false-negative results in the lentiform nucleus, two false-negative results in the insular cortex, and one false-positive finding for the insular cortex. The remainder of the infarcts were correctly identified. The original clinical reading, performed at the time of presentation, produced five false-negative interpretations for the patient group, all of which were correctly identified by the automated algorithm. CONCLUSION: We present an automated method for identifying potential areas of acute ischemia on CT scans. This approach can be extended to other brain regions and vascular territories and may aid in the interpretation of CT scans in cases of hyperacute stroke.

Brain Mapping↗
PubMed2002

Functional localization of brainstem and cervical spinal cord nuclei in humans with fMRI.

BACKGROUND AND PURPOSE: To our knowledge, no published functional map of the human lower brainstem exists. Our purpose was to use 1.5-T functional MR imaging (fMRI) to visualize the location of cranial nerve (CN) nuclei and other pontine, bulbar, and cervical spinal cord nuclei by using specific sensory stimulation or motor performance. METHODS: We localized nuclei by using cross-correlation analysis of regional blood oxygen level-dependent (BOLD) signal intensity during specific motor and sensory procedures based on known functions of specific nuclei. Statistical parametric mapping (SPM) analysis was used for comparison. Head, cardiac, and respiratory motion artifact correction was applied. Histologic atlases aided localization. RESULTS: We obtained evidence of localization of the following nuclei by using tests, as follows: main trigeminal sensory (CN V), brushing the face; abducens (CN VI), left-right eye movement; facial (CN VII), smiling and lip puckering; hypoglossal (CN XII), pushing the tongue against the hard palate; nucleus ambiguus, swallowing; nucleus tractus solitarii (NTS), tasting a sweet-sour-salty-bitter mixture; nucleus cuneatus, finger tapping; and cervical spinal cord levels C1-C3, tongue movement to activate the strap muscles. Activation of cortical motor and sensory areas and somatosensory thalamus corresponded with the tasks and sites of brainstem activation. Head movement was minimal, typically less than 1 mm in all three axes. CONCLUSION: With 1.5-T fMRI, the CN nuclei of the pons and medulla, and other nuclei of the lower brainstem and cervical spinal cord, can be localized in awake humans with specific sensory stimulation or motor performance.

Abducens Nerve↗
PubMed1997

SPECT imaging of normal subjects with technetium-99m-HMPAO and technetium-99m-ECD.

UNLABELLED: Technetium-99m-HMPAO and 99mTc-ECD have been used for regional cerebral blood flow (rCBF) studies using SPECT. However, details of the normal perfusion patterns of these agents still remain to be clarified. HMPAO-SPECT and ECD-SPECT images of normal individuals were investigated using an anatomical standardization technique. METHODS: Twenty healthy subjects participated in this study. In 10 of these, regional cerebral perfusion was measured with HMPAO, and in the other 10, ECD was used. All SPECT images were globally normalized to 50 counts/voxel, and then, each SPECT image was transformed into a standard brain anatomy format with the aid of x-ray CT of each subject and a computerized human brain atlas system (HBA). Mean and s.d. images for each tracer were calculated on a voxel-by-voxel basis. For comparison of these SPECT images with blood flow, rCBF images were generated using PET in a separate group of 10 healthy male subjects during an eyes-closed resting state. The PET images were globally normalized to 50 ml/100 g/min and anatomically standardized using each subject's MRI and the HBA for the SPECT images. RESULTS: In the HMPAO-SPECT images, relatively high radioactivities Were observed in the basal ganglia and cerebellum. In the ECD-SPECT images, high levels were observed in the medial aspect of the occipital lobe. These regions with high radioactivity were not apparent in the rCBF-PET images. CONCLUSION: While both HMPAO and ECD have been used to investigate rCBF, their perfusion patterns differ from rCBF-PET images. This presumably reflects differences in the mechanism of accumulation of each agent in the brain. For clinical diagnoses, these patterns must be taken into consideration.

Adult↗
PubMed1998

Intersubject variability of functional areas in the human visual cortex.

Intersubject variability of striate and extrastriate areas was mapped by conjoined use of positron emission tomography (PET) and magnetic resonance imaging (MRI). We used two dynamic bowtie-shaped random-dot patterns centered symmetrically around the vertical- and horizontal-meridian, respectively, presented during sequential PET scans in 11 subjects. Control condition was simple fixation on a central dot in absence of a surrounding random dot pattern. V1, V2, VP, V3, V3a, V4, V5, and "wordform" areas were identified. After spatial normalization to Talairach atlas space, mean locations and standard deviations about these mean locations for x-, y-, and z-axes were calculated for each area in both hemispheres and compared for differences. The mean standard deviation for all axes across all areas tested was found to be small (4.9 mm). No significant differences were found in the mean standard deviations for the x-, y-, and z-axes in the left hemisphere vs. their counterparts in the right hemisphere. However, when mean standard deviations in both hemispheres were polled together by axis, the mean standard deviation for the y-axis (5.3 mm) was found to be significantly different from the mean standard deviation for the x-axis (4.3 mm). Furthermore, in the left hemisphere, the mean standard deviation for the z-axis (5.7 mm) was significantly greater than the mean standard deviation for the x-axis (3.9 mm). The values reported in this study for mean location and standard deviation of visual areas can be used to establish confidence intervals for distinguishing normal variations from pathology and consequent brain reorganization.

Adolescent↗
PubMed1999

Anatomic validation of spatial normalization methods for PET.

UNLABELLED: Spatial normalization methods, which are indispensable for intersubject analysis in current PET studies, have been improved in many aspects. These methods have not necessarily been evaluated as anatomic normalization methods because PET images are functional images. However, in view of the close relation between brain function and morphology, it is very intriguing how precisely normalized brains coincide with each other. In this report, the anatomic precision of spatial normalization is validated with three different methods. METHODS: Four PET centers in Japan participated in this study. In each center, six normal subjects were recruited for both H2(15)O-PET and high-resolution MRI studies. Variations in the location of the anterior commissure (AC) and size and contours of the brain and the courses of major sulci were measured in spatially normalized MR images for each method. Spatial normalization was performed as follows. (a) Linear: The AC-posterior commissure and midsagittal plane were identified on MRI and the size of the brain was adjusted to the Talairach space in each axis using linear parameters. (b) Human brain atlas (HBA): Atlas structures were manually adjusted to MRI to determine linear and nonlinear transformation parameters and then MRI was transformed with the inverse of these parameters. (c) Statistical parametric mapping (SPM) 95: PET images were transformed into the template PET image with linear and nonlinear parameters in a least-squares manner. Then, coregistered MR images were transformed with the same parameters used for the PET transformation. RESULTS: The AC was well registered in all methods. The size of the brain normalized with SPM95 varied to a greater extent than with other approaches. Larger variance in contours was observed with the linear method. Only SPM95 showed significant superiority to the linear method when the courses of major sulci were compared. CONCLUSION: The results of this study indicate that SPM95 is as effective a spatial normalization as HBA, although it does not use anatomic images. Large variance in structures other than the AC and size of the brain in the linear method suggests the necessity of nonlinear transformations for effective spatial normalization. Operator dependency of HBA also must be considered.

Brain↗
PubMed2004

A meta-algorithm for brain extraction in MRI.

Accurate identification of brain tissue and cerebrospinal fluid (CSF) in a whole-head MRI is a critical first step in many neuroimaging studies. Automating this procedure can eliminate intra- and interrater variance and greatly increase throughput for a labor-intensive step. Many available procedures perform differently across anatomy and under different acquisition protocols. We developed the Brain Extraction Meta-Algorithm (BEMA) to address these concerns. It executes many extraction algorithms and a registration procedure in parallel to combine the results in an intelligent fashion and obtain improved results over any of the individual algorithms. Using an atlas space, BEMA performs a voxelwise analysis of training data to determine the optimal Boolean combination of extraction algorithms to produce the most accurate result for a given voxel. This allows the provided extractors to be used differentially across anatomy, increasing both the accuracy and robustness of the procedure. We tested BEMA using modified forms of BrainSuite's Brain Surface Extractor (BSE), FSL's Brain Extraction Tool (BET), AFNI's 3dIntracranial, and FreeSurfer's MRI Watershed as well as FSL's FLIRT for the registration procedure. Training was performed on T1-weighted scans of 136 subjects from five separate data sets with different acquisition parameters on separate scanners. Testing was performed on 135 separate subjects from the same data sets. BEMA outperformed the individual algorithms, as well as interrater results from a subset of the scans, when compared for the mean Dice coefficient, a rating of the similarity of output masks to the manually defined gold standards.

Adult↗
PubMed2006

Automatic anatomical brain MRI segmentation combining label propagation and decision fusion.

Regions in three-dimensional magnetic resonance (MR) brain images can be classified using protocols for manually segmenting and labeling structures. For large cohorts, time and expertise requirements make this approach impractical. To achieve automation, an individual segmentation can be propagated to another individual using an anatomical correspondence estimate relating the atlas image to the target image. The accuracy of the resulting target labeling has been limited but can potentially be improved by combining multiple segmentations using decision fusion. We studied segmentation propagation and decision fusion on 30 normal brain MR images, which had been manually segmented into 67 structures. Correspondence estimates were established by nonrigid registration using free-form deformations. Both direct label propagation and an indirect approach were tested. Individual propagations showed an average similarity index (SI) of 0.754+/-0.016 against manual segmentations. Decision fusion using 29 input segmentations increased SI to 0.836+/-0.009. For indirect propagation of a single source via 27 intermediate images, SI was 0.779+/-0.013. We also studied the effect of the decision fusion procedure using a numerical simulation with synthetic input data. The results helped to formulate a model that predicts the quality improvement of fused brain segmentations based on the number of individual propagated segmentations combined. We demonstrate a practicable procedure that exceeds the accuracy of previous automatic methods and can compete with manual delineations.

Adult↗
PubMed2002

Differences in resting state regional cerebral blood flow assessed with 99mTc-HMPAO SPECT and brain atlas matching between depressed patients with and without tinnitus.

An increased occurrence of major depressive disorder has been reported in tinnitus patients, and of tinnitus in depressive patients. Involvement of several Brodmann areas (BAs) has been reported in tinnitus perception. The aim of this study was to assess the regional cerebral blood flow (rCBF) changes in depressed patients with and without tinnitus. The rCBF distribution at rest was compared among 45 patients with a lifetime prevalence of major depressive disorder, of whom 27 had severe tinnitus, and 26 normal healthy subjects. 99mTc-hexamethylenepropylene amine oxime (99mTc-HMPAO) single photon emission computed tomography (SPECT), using a three-headed gamma camera, was performed and the uptake in 34 functional sub-volumes of the brain bilaterally was assessed by a computerized brain atlas. Decreased rCBF in right frontal lobe BA 45 (P<0.05), the left parietal lobe BA 39 (P<0.00) and the left visual association cortex BA 18 (P<0.05) was found in tinnitus patients compared with non-tinnitus patients. The proportion of tinnitus patients with pronounced rCBF alterations in one or more of the temporal lobe BAs 41+21+22 was increased compared to gender matched controls (P<0.00) and patients without tinnitus (P<0.05). Positive correlations were found between trait anxiety scales from the Karolinska Scales of Personality and rCBF in tinnitus patients only in three limbic BAs (P<0.01), and inverse correlations in non-tinnitus patients only in five BAs subserving auditory perception and processing (P<0.05). rCBF differences between healthy controls and depressed patients with and without tinnitus were found in this study. The rCBF alterations were distributed in the cortex and were particularly specific in the auditory cortex. These findings suggest that taking audiological symptoms into account may yield more consistent results between rCBF studies of depression.

Age Factors↗
PubMed2000

Bone age determination in a paediatric population as an indicator of nutritional status.

The United Mission to Nepal Tansen Project is in the hill country, 300 km West of Kathmandu. This 40-year-old service centre's major emphasis has been on clinical and community medicine and education. Agronomy, forestry, water resources development, adult literacy, etc., have also been part of the project's outreach. We had long noted that the children of all of the various tribal groups in the area are small for their age as compared with children in developed countries. Fracture care X-rays were examined to reveal delay in ossification and in physeal closure. Using the standards found in the Radiographic Atlas of Skeletal Development of the Hand and Wrist, we quantified this apparent delay by determining the bone age of all patients presenting at the hospital with upper limb injuries requiring X-ray. The collection of data was limited to 100 days and to those under the age of 21. Two hundred and nineteen patients' data were analysed. We found that bone maturation delay was very common and often severe. The average bone age among the 219 was 28% below chronological age. That is, 60% of all fell two standard deviations below the norm: i.e. two-thirds of all 9 year olds had the expected skeletal development of 6 year olds in Boston, USA. Dental age was also analysed using deciduous tooth shedding and tooth eruption patterns. Dental age retardation averaged 21%, but a larger per cent had normal eruption dates. Other physical and sociological data were included in a questionnaire completed for each patient. Among the variables examined, poverty alone appeared to be the major mover. We believe that national small stature is a result of lifelong community dietary inadequacy.

Age Determination by Skeleton↗
PubMed2000

The optimal transarticular c1-2 screw length and the location of the hypoglossal nerve.

BACKGROUND: Injury to the hypoglossal nerve is a complication associated with transarticular C1-2 screw placement. This complication can be caused by a misdirected or too long screw. Little is known about the optimal screw length and its relationship to the hypoglossal nerve. METHODS: Twenty cervical spine specimens were used to study the optimal length of the transarticular C1-2 screw. Using the Magerl technique, a 3.0 mm drill bit was inserted into the C2 lateral mass, passing through the C1-2 facet joint and penetrating the upper portion of the ventral cortex of the lateral mass of the atlas. After drilling, the hole length was measured between the dorsal cortex of the C2 inferior articular process and the ventral cortex of the C1 lateral mass. In addition, six sagittal-sectioned cadavers were carefully dissected to observe the location of the hypoglossal nerve in the anterior aspect of the atlantoaxial region. RESULTS: The results of the measurements showed that the mean optimal screw path length for all specimens was 38.1 +/- 2.2 mm with a range of 34-43 mm. There was no significant difference between sexes in the screw path length (p 0.05). The hypoglossal nerve lies vertically in front of the lateral portion of the C1 lateral mass and the C1-2 facet joint. The area where the hypoglossal nerve lies is approximately 2-3 mm lateral to the middle of the anterior aspect of the C1 lateral mass. CONCLUSIONS: This study suggests that the mean optimal transarticular C1-2 screw length may be 38 mm; however, the determination of the accurate optimal C1-2 screw length should be made on an individual basis. Risk to the hypoglossal nerve can be eliminated if Magerl's technique is performed exactly.

Aged↗