A morphometric anatomical and comparative study of the foramen magnum region in a Greek population

Clinical and anatomical importance of foramen magnum and craniocervical junction structures in the perspective of surgical approaches

This study was conducted to investigate the clinical and anatomical importance of the relevant region from the perspective of surgical approaches by determining the morphometric analysis of the craniocervical junction and foramen magnum (FM) region and determining their distances from important anatomical points. This research was carried out with 59 skulls found at the Anatomy Laboratories of Erciyes and Ankara Medipol University. Metric measurements of FM and condyle, FM shape, condyle-fossa relationship, and pharyngeal tubercle (PT) were made in mm-based dry bone samples of unknown age and sex. The distance between the anterior notches and the FM was 87.01±4.35, the distance between the anterior notches and the PT was 77.70±4.24, the distance between the PT-sphenooccipital junction was 13.23±2.42, and the FM index was 81.86±7.47. The anteroposterior and transverse lengths of FM were determined as 33.80±2.99 and 27.72±2.30, respectively. The morphometric and morphological data available regarding the craniocervical junction showed significant differences between populations. Comprehensive knowledge of this topic will provide a better approach to treat Arnold Chiari Malformation, FM meningiomas, and other posterior cranial fossa lesions. Therefore, we believe that FM and craniocervical junction morphology will be a guide not only for anatomists, but also for radiologists, neurosurgeons, ENT surgeons, and orthopedists.

Radiological and Morphometric Study of the Emissary Foramens and Canal in the Posterior Cranial Fossa of the Human Skull with Its Neurosurgical Significance

Objective  The posterior condylar canals (PCCs), posterior condylar veins (PCVs), occipital foramen (OF), and occipital emissary vein (OEV) are potential anatomical landmarks for surgical approaches through the lateral foramen magnum. We performed the study to make morphometric and radiological analyses of the various emissary foramens and vein in the posterior cranial fossa. Methods  Morphometric study were performed on 95 dry occipital bones and radiological analyses on computed tomography (CT) angiography images of 150 patients. The number of OFs on both sides was recorded and PCC length and mean diameters of the internal and external orifices of PCC were measured for bony specimens. Prevalence of PCV and PCV size was investigated using CT angiography. Results  Mean PCC length was higher in the left side (9.85 ± 2.5). Mean diameter of the internal orifice and the external orifice diameter were almost the same. The majority of PCCs (75-79.33%) had 2 to 5 mm diameter; only 4 to 9.2% were small in size (< 2 mm). In CT angiography, PCV was not identified in 23 (15.33%) patients. PCVs were located bilaterally in 105 (70%) and unilaterally in 22 (20.5%) patients. Only 11.3% of PCVs were large in size (> 5 mm), 80% of PCVs were medium sized (2-5 mm), and 8.6% were small sized (< 2 mm). Conclusion  Normal values of OF, PCC, PCV, and OEV could serve as a future reference for the understanding of the physiology of craniocervical venous drainage, which is necessary to avoid surgical complications and can also serve as a guide to surgical interventions for pathologies of the posterior cranial fossa, such as tumors and injuries.

Anatomical Evaluation of the Foramen Magnum on Cone-Beam Computed Tomography Images and Review of Literature

Background and objective The morphology and morphometry of the foramen magnum (FM), which provides a passageway to vital neurological structures that relay information to and from the brain and spinal cord, are significant for many surgical approaches and applications. It was aimed to investigate the morphometric and morphological features of the FM on the cone-beam computed tomography (CBCT) images and to review the literature in detail. Methods CBCT images of 400 individuals (200 males, 200 females, aged between 18 and 65) were evaluated by Planmeca Romexis Viewer. The length, width, perimeter, and area of the FM were examined and samples were classified according to shape. Also, the FM index (FMI) was calculated. Results The mean values of the length, width, and perimeter were found to be 36.75±2.50 mm, 32.55±2.93 mm, and 108.35±7.50 mm, respectively. The area of FM was found to be 941.81±128.26 mm², 946.83±127.39 mm², and 895.76±123.50 mm² with Planmeca Romexis Viewer, Radinsky formula, and Teixeira formula, respectively. All parameters were significantly larger in males than females. There was no correlation between age and these parameters. Also, seven shapes were determined for FM, and the most common shape was oval. FM index was evaluated according to the Martin and Saller classification. It was found that 16.5% of the cases belonged to the narrow, 16% belonged to the medium, and 67.5% to the large FM index. There was no correlation between age and FM index. Conclusion Morphometric and morphological features of the FM located in the craniovertebral junction (CVJ), which is a highly complex area, are variable. Surgical procedures and approaches in this region are essential due to the high mortality rate. For this reason, anatomical structures in these regions should be well known before surgery. The quantitative data presented in this study, which made a detailed literature comparison, may assist in surgical procedures around the FM and the planning of these procedures.

Occipital condyle screw fixation viability according to age and gender anatomy: A computed tomography-based analysis

OBJECTIVE

To assess the Occipital condyle morphology in an all-age population of Northeastern Mexico, and determine age and gender related changes for surgical viability.

METHODS

A total of 175 consecutive HRCT scans were included and divided into 5 age groups. The condylar length, width, height, sagittal angle, anterior, posterior and medial intercondylar distances, and intercondylar angle of the OC were measured.

RESULTS

Mean condylar length, width, and height in total population were 20.58 mm, 9.42 mm, and 9.02 mm, respectively. Differences were observed in most morphometric parameters when comparing age groups. Significant intergender differences in total population were observed in most parameters, when individualizing each age group the height remained significant in all. The group with the least height measurement was aged 5-9 years, this however, could allow the OC screw (≥6.5 mm) placement.

CONCLUSION

Differences in most morphometric parameters of OC were observed between age groups and gender, particularly patients with 5-9 years. However, all groups presented a minimum height that allows the placement of a standard screw. A preoperative imaging study is always recommended due to the variability and complexity of the region.

The Clock Is Ticking - Brain Atrophy in Case of Acute Trauma?

Objective

Brain atrophy and brain herniation are gaining a lot of attention separately, but a limited amount of studies connected them together, and because of this, we are going to review and examine the subject in the current meta-analysis.

Methods

The authors collected data reporting brain atrophy of alcoholic and schizophrenic cause, as well as data on control patients, all of which was published on MEDLINE between 1996 and 2018. The included 11 articles were processed with a statistical program.

Results

We found that the pericerebral space is unequal among the groups, while the intracranial volume is strongly correlated to the biggest foramen of the body. The effect of this inequality, however, is expressed in emergency cases, where the patients with brain atrophy will have more time before the final stage of brain herniation.

Conclusion

The current study raises a controversial issue that requires careful investigation and high attention from the health care personnel.

Anatomical Variation in Morphometry and Morphology of the Foramen Magnum and Occipital Condyle in Dried Adult Skulls

BACKGROUND

The foramen magnum (FM) is the largest opening and is outlet through which medulla oblongata and spinal cord along with meninges, vertebral arteries, anterior and posterior spinal arteries, tectorial membrane, alar ligaments, and spinal branch of the accessory nerve. Occipital condyle (OC) is an important part of craniovertebral or craniocervical junction located anterolaterally on either side of the FM. The objective of the study was to assess variations of FM and OC in Ethiopian dried adult skulls.

METHODS

Observation-based descriptive study design was employed. The study was undertaken in 54 FM and 108 OC of 54 adult Ethiopian skulls. The morphometry of FM and OC were determined using a sliding vernier caliper.

RESULTS

The mean values of anteroposterior and transverse diameters of the FM were 35.19 and 30.17 mm, respectively, and the mean area of the FM was 853.36 mm. The shapes of FM were determined as round in 22.2%, oval in 18.5%, egg like in 20.4%, triangular in 3.7%, pentagonal in 11.1%, hexagonal in 7.4%, irregular in 13%, and rectangular in 3.7% of the cases. The mean length of right and left OC was 25.69 and 26.96 mm, respectively, and the mean widths of the right and left OC were 12.76 and 13.04 mm, respectively.

CONCLUSION

Our study identified various shapes of FM and diameter. The anteroposterior diameter is greater than the transverse diameter. The morphometric study of OC confirmed the length of left side is significantly greater than the right side.

Comparison of Three Methods Used for Estimating Area of Foramen Magnum

OBJECTIVE

To compare whether there are any differences between the 3 methods used for measure area of foramen magnum (FM) in skulls.

METHODS

The FMs of 150 skulls were examined. Antero-posterior diameter, transverse diameter were measured using by Vernier caliper. The area of the FM was calculated by using 2 different formulas as described previously by Radinsky and Teixeira.The authors also applied stereological assessment method for estimating the surface area of FMs. The area was calculated 3 times manually using stereological point grid system for each skull.The authors compared the mean surface area of FMs obtained from each of these 3 methods estimating surface area of FMs whether there were any significant differences in between their results.

RESULTS

The mean areas of the FMs estimated according to Teixeria formula, Radinsky formula, and Cavalieri stereological method were respectively as follows: 790.47 ± 99.86 mm, 783.66 ± 99.34 mm, and 748.06 ± 100.19 mm. The authors observed significant differences (P < 0.05) in between the mean surface areas of FMs obtained from each of these 3 methods used for estimating the area.

CONCLUSION

There were significant differences (P < 0.05) in between the mean surface areas of FMs obtained from each of these 3 methods used for estimating the area.

Morphological and Morphometric Analysis of Foramen Magnum: An Anatomical Aspect

OBJECTIVE

To investigate the detailed morphological and morphometric analysis of foramen magnum (FM) in dry cranii.

METHODS

One hundred fifty skulls of unidentified sex were macroscopically examined and were photographed with Canon 400B (55 mm objective). According to tooth eruption of the skulls, they were accepted as adults. None of the examined skulls showed signs of prior cranial surgery, malformation, or trauma. The evaluated study parameters that were recorded with Vernier caliper in millimeter were as follows: antero-posterior diameter from Basion to Opisthion, transverse diameter (largest distance between the lateral margins of the FM), and the shape of the FM (Fig. 1). The shape of the FM was determined according to FM index that was calculated by dividing antero-posterior diameter by transverse diameter. When FM index was found greater than or equal to 1.2, the foramen was accepted to be oval in shape. Whereas the FM index was found less than 1.2, the foramen was accepted to be round in shape The area of the FM was calculated by using 2 different formulas as described previously by Radinsky (/4 × π × w × h) and Teixeira (π × {(h + w)/4}2), and "π" was accepted as 3.14 in both formulas.

RESULTS

The results of descriptive statistics and areas of the FMs were presented in Table 1. The mean antero-posterior diameter and transverse diameter of anteroposterior diameter by transverse diameters were found as 34.38 ± 2.38 and 28.95 ± 2.19, respectively. The mean area of the FMs estimated by Teixeria formula was determined significantly larger than the mean area of the FMs estimated by Radinsky formula (P <0.001). According to estimated FM index of the 150 adult dry skulls, 87 (58%) of skulls were described as being round in shape and 63 (42%) of skulls were described as being oval in shape (Fig. 1).

CONCLUSION

The surgeons must comprehend regarding the detailed morphological and morphometric features of FM to avoid vital complications during the surgical procedures.

Morphological and Morphometric Analysis of Hypoglossal Canal in North Indian Dry Skulls and It's Significance in Cranial Base Surgeries

INTRODUCTION

Hypoglossal Canal (HC) is a paired bony passage which is situated above the Occipital Condyle (OC) and transmits hypoglossal nerve and blood vessels. Studies on the osteotic variations of HC has been a field of considerable interest to research workers especially because of its clinical, radiological and surgical significance.

AIM

The aim of the present study was to analyze the morphological and morphometric features of HC and its topographical relationship with OC.

MATERIALS AND METHODS

The present study was done on 50 human dry skulls. The HC was looked for presence of spur and septa along with its location in the canal and were classified into different types accordingly. The distance of extracranial and intracranial openings of HC from the posterior end of OC was measured by Sliding Vernier caliper. Angle of inclination of HC with the midsagittal plane was measured with the help of goniometer.

RESULTS

In the present study, we observed osteotic variations in the HC in 52% skulls. The spur (Type 2) was seen in 28% and incomplete septa (Type 3) was noted in 26% skulls. In some cases, spur and septa were seen in different locations of same HC. However, complete septa (Type 4) were not observed in our study. Spur and septa, both were present more frequently on the left side. The external and internal distance of HC from posterior end of OC was more on the left side in comparison to the right side. The anterior angle of HC to the midsagittal plane is less in comparison to posterior angle in case of double internal opening of HC.

CONCLUSION

The present study regarding morphologic and morphometric analysis of HC and its relation to the OC will provide important information in North Indian population. It will enable effective and reliable surgical intervention in the area of HC and craniovertebral junction leading to better postoperative outcome.

A morphometric study of the atlas occipitalization and coexisted congenital anomalies of the vertebrae and posterior cranial fossa with neurological importance

PURPOSE

Our study highlights the morphometry of the partial and complete atlas occipitalization (AOZ), its coexistence with fusions of the 2nd and 3rd cervical vertebrae and morphological and morphometric abnormalities of the posterior cranial fossa that are of paramount neurological importance.

METHODS

One hundred and eighty adult dry skulls, the atlas and axis vertebrae were examined.

RESULTS

Four skulls (2.2 %) showed AOZ. Two of them (1.1 %) presented a partial AOZ, one male skull (0.6 %) a complete AOZ and a female skull (0.6 %) had a fused left hemiatlas with the occipital bone and a fusion of the 2nd and 3rd cervical vertebrae. The inner anteroposterior and transverse diameters of the foramen magnum (FM) in the control group were 34.6 ± 3.46 and 29.3 ± 3.47 mm. Only the skull with the complete AOZ had a reduced outer anteroposterior diameter of the FM (29.8 mm), while no specimen was found with a reduced transverse diameter. A wide total decrease (range 13.1-50.9 %) in the surface area of the FM in skulls with AOZ was detected. Extracranial, the clivus length in two skulls with AOZ was smaller than the normal range. No skull was detected with a reduction in the intracranial length of the clivus. All skulls with the AOZ had a vermian fossa.

CONCLUSIONS

The study adds important morphometric details about the partial and complete AOZ and correlates the phenomenon of synostosis with the narrowing of the FM, particularly in the case of complete AOZ. Awareness of the AOZ and other fusions of the upper cervical vertebrae and their topographical relations and attendant problems are of paramount importance to surgeons, when operate to the craniocervical junction, or interpret imaging studies to plan a safe surgery for nerve or spinal tissue decompression.

Quantitative normal thoracic anatomy at CT

Automatic anatomy recognition (AAR) methodologies for a body region require detailed understanding of the morphology, architecture, and geographical layout of the organs within the body region. The aim of this paper was to quantitatively characterize the normal anatomy of the thoracic region for AAR. Contrast-enhanced chest CT images from 41 normal male subjects, each with 11 segmented objects, were considered in this study. The individual objects were quantitatively characterized in terms of their linear size, surface area, volume, shape, CT attenuation properties, inter-object distances, size and shape correlations, size-to-distance correlations, and distance-to-distance correlations. A heat map visualization approach was used for intuitively portraying the associations between parameters. Numerous new observations about object geography and relationships were made. Some objects, such as the pericardial region, vary far less than others in size across subjects. Distance relationships are more consistent when involving an object such as trachea and bronchi than other objects. Considering the inter-object distance, some objects have a more prominent correlation, such as trachea and bronchi, right and left lungs, arterial system, and esophagus. The proposed method provides new, objective, and usable knowledge about anatomy whose utility in building body-wide models toward AAR has been demonstrated in other studies.

The anatomical perspective of human occipital condyle in relation to the hypoglossal canal, condylar canal, and jugular foramen and its surgical significance

Background:

The transcondylar approach (TCA) has gained importance in recent era which enables shorter and direct route to access the lesions ventral to the brainstem. The important step in this approach is resection of the occipital condyle (OC). The detailed knowledge of bony anatomy of OC and its relation to the hypoglossal canal (HC), condylar canal (CC), and jugular foramen (JF) is very important to avoid any iatrogenic injury during craniovertebral surgeries. The aim of the present study is to conduct a morphometric and morphological study and note the variations of the OC and the structures surrounding it in North Indian population.

Materials and Methods:

The study was carried out on 100 OC. Morphometric measurements of OC and the distances of HC and JF from the posterior end of OC were noted. In addition, the extent of the HC and JF in relation to OC, presence or absence of CC, shape of the OC, and its articular facet were also noted.

Results:

The incidence of short OC was seen in 13% skulls. The most common shape of OC was oval or rhomboid. Even though the articular facet was convex in majority of skulls but flat (10%) and concave (1%) were also observed. The external and internal distance of HC from the posterior end of OC was13.83 mm and 10.66 mm on the right side and 15.02 mm and 11.89 mm on the left side. The OC was related in its middle 1/3 to the HC in 15% skulls and to the whole extent of JF in 3% skulls. Thirty-four percent skulls displayed the septa in the HC. The CC was present bilaterally in 38% skulls and unilaterally in 40% skulls.

Conclusion:

The OC and related structures such as HC, CC, and JF are likely to have variations in respect to morphometry and morphology. This study may prove helpful to neurosurgeons operating in this field, especially during TCA where neurovascular structures emerging from these canals and foramen are more vulnerable to injury.

Anatomic study of the occipital condyle and its surgical implications in transcondylar approach

Background:

Craniovertebral surgeries require the anatomical knowledge of craniovertebral junction. The human occipital condyle (OC) is unique bony structure connecting the cranium and the vertebral column. A lateral approach like transcondylar approach (TA) requires understanding of the relationships between the OC, jugular tubercle, and hypoglossal canal. Hence, the aim of the present study was to analyze the morphological variations in OCs of dry adult human skull.

Materials and Methods:

The study was carried out on 142 OC of 71 adult human dry skulls (55 males and 16 females). Morphometric parameters such as length, width, thickness, intercondylar distances, and the distances from the OC to the foramen magnum, hypoglossal canal and jugular foramen were measured. In addition, the different locations of the hypoglossal canal orifices in relation to the OC and different shapes of the OC were also noted.

Results:

The average length, width and height of the OC were found to be 2.2, 1.1 and 0.9 cm. The anterior and posterior intercondylar distances were 2.1 and 3.9 cm, respectively. Maximum and minimum bicondylar distances were 4.5 and 2.6 cm, respectively. The intra-cranial orifice of the hypoglossal canal was found to be present in middle 1/3^rd in all skulls (100%), and extra-cranial orifice of the hypoglossal canal was found to be in anterior 1/3^rd (98%) in relation to OC. The oval shaped OC (22.5%) was the most predominant type of OC observed in these skulls.

Conclusion:

Occipital condyle is likely to have variations with respect to shape, length, width and its orientation. Therefore, knowledge of the variations in OC along with careful radiological analysis may help in safe TAs during skull base surgery.