Dry Human Skulls Research Articles

Morphometric measurements of anterior clinoid process in relation to parasellar osseous structures and their clinical significance

This study is to analyze the morphometry of anterior clinoid process (ACP) and the surrounding parasellar structures which is important for the surgeries related to cavernous sinus, ICA, and basilar artery. A cross-sectional study has been done on 77 adult human dry skulls among North Indian population. The length, width, thickness of ACP and distance between ACP to OS, distance between two ACPs, distance between PCPs, distance between ACP to PCP were measured using digital vernier caliper. The mean and standard deviation was calculated and paired t-test was applied for the comparison. The mean length and width and thickness of ACP was 8.72±0.94 mm, 8.13±1.16 mm and 1.10±0.44 mm on right and 8.57±0.91mm, 8.05±1.24 mm and 1.40±0.41mm on left side. The average distance between the ACP tip to OS and ACP and PCP tip was 6.01±1.11mm and 8.79±1.49mm on the right and 5.90±0.99mm and 8.47±1.49mm left side. The mean distance between the ACP tip and PCP tip was 20.10±2.36 mm and 12.63±2.03 mm respectively. We did not find any significant difference of morphometric parameters between the right and the left side. The anatomical knowledge of these structures and its variation will help surgeons to plan surgery around the parasellar region.

Supraorbital Foramina and Supraorbital Notches in Unknown Dry Human Skulls- A Review of Literatures

In craniofacial surgery and supraorbital nerve block, the anatomy of the supraorbital region is crucial. Injury to the supraorbital neurovascular bundle is a frequent complication during the anterior orbital approach, blepharoplasty, fronto-glabellar reconstruction flap, and in the supraorbital nerve blocks during treatment of maxillofacial wounds and treatment of migraine. However, there are a lot of variations of supraorbital foramina and notches among different groups of populations of various races. Morphometric analysis of supraorbital foramina and notches have been carried out on unknown dry adult human skulls by authors. In these studies, two planes have been made use of, namely sagittal and transverse planes of the skulls along with vertical & horizontal dimensions. In addition, the positions of notches and foramina in relation to midline as well as frontozygomatic sutures were also measured. Various combinations of the presence or absence of supraorbital foramina and notches were also noted. The study on supraorbital foramina and notches has profound anthropological importance, anesthetics importance, and surgical importance. Various studies' findings and conclusions on notches and foramina are being considered for the study of review articles

Sexual Dimorphism in Endocranial Capacity of Dry Human Skulls in Central India Region

Cranial capacity is indicative of brain volume and is important for deciding racial and sexual characteristics in physical anthropological studies. It is measured both directly by filling the cranial cavity with various materials like lead shots, mustard, cast materials etc and indirectly by using derivation formulae. In the present study, volume of the cranial cavity is measured by using mustard seeds and calibrated glass cylinder. The range of cranial capacity is 1120- 1650 cc and 800-1280 cc in male and female skulls respectively. Cranial Capacity was statistically significant, t (258) = -16.94, p = <.001, 95% confidence interval [-203.13, 160.6] it is an important measured parameter to differentiate male and female skulls. The results are useful for anatomists, medicolegal experts and anthropologists.

Sexual Dimorphism in Endocranial Capacity of Dry Human Skulls in Central India Region

Sexual Dimorphism in Endocranial Capacity of Dry Human Skulls in Central India Region

Study of the Variations of Asterion, Pterion & Inion in Human Dry Skulls & its Anthropological importance

Background and objectives: Asterion is the meeting point of three bones namely parietal, temporal and occipital bones in the norma lateralis of all human skulls the variations showed a pattern of formations. Pterion is the point of convergence of the sutures between the frontal, sphenoid, parietal and squamous temporal bones. Asterion have profound surgical importance. 
 Materials and methods: Good intact skulls from different medical college of Nepal were used for the present study. Each skull was studied in detail regarding the formation of Asterion, Pterion on both sides and associated findings were observed. Sixty eight dry unknown human skulls constituted the materials for the present study. The observation was made on Asterion, Pterion & Inion. This study was done in the departments of Anatomy in different medical colleges of Nepal between the years 2019-2021.
 Results: Incidence of asterion with wormian bones on the right side was 4.41% that of the left side 5.88%. More number of H shaped pterion on the right side [80.82%} than on left side [70.94%). Presence of Wormian bones more on the right side [7.69%] than on the left side [2.94%) were observed.
 Conclusion: The knowledge of the formation of asterion and the presence of wormian bones in the sutures at the site and its effect should be known not only to the Anatomists but also to the Radiologist and the Neurosurgeons because it has profound neurosurgical importance. Hence this study has been done and reported.

Morphometric Study on Types of Asterion in Dry Human Skull of Nepalese Origin

Introduction: The asterion is important bony landmark of skull important for surgical approach to the posterior cranial fossa. The variation is type of asterion is due to presence or absence of lambdoidal suture, parietomastoid suture and occipitomastoid suture. Asterion is starry or triangular depression located 2.5cm behind the upper part of root of ear. Asterion is meeting point of lambdoidal suture, parietomastoid suture and occipitomastoid suture. Materials and Methods: Altogether 26 dry adult human skulls were collected from Department of Anatomy at School of Basic Sciences in Chitwan Medical College for research. Gender and ethnicity were undefined. All damaged skull and newborns are excluded. Both sides of skull were studied for location and type of asterion. The types of asterion were noted by observing the presence or absence of all three sutures. Photograph were taken and studied. Statistical analysis was done using SPSS 17. Results: Twenty-six human skulls of unknown gender were examined. Two types of asterion were observed. The type I asterion was 88.5 percent and type II asterion was 11.5 percent on both side of skull. Conclusion: we believe that there are different types of asterion present in human skull. Asterion is the important surgical landmark. Thereby, the finding may be helpful in surgical approach and intervention.

Evaluation of a low dose CBCT protocol in reliably detecting simulated facial fractures associated with sports injuries.

<h3>Objective</h3> To evaluate the value of a low dose CBCT protocol that uses 180-degree rotation scan in the detection of simulated facial fractures, compared to the standard 360-degree rotational protocol. <h3>Study Design</h3> Three dry human skulls were selected for imaging. The skulls were scored in 11 locations using a dental hand piece and diamond bur to simulate small cortical bone facial fractures that best represent the most commonly occurring fractures in sports. Fractures were simulated bilaterally and centrally in the mandibular symphysis, angle, condyles, zygomatic process of temporal bones, and the zygomatic process of the maxilla. Wax was used to simulate a deviated/fractured nasal septum. CBCT scans of the skulls were scanned using 180 degree and 360 degree rotation. Two observers evaluated the images using all 3 multiplanar reformations, volumetric renderings, and maximum intensity projections reconstructed with InVivo6 software to identify and measure the fractures on axial, sagittal, and coronal views. Measurements of the length of the fractures were made on the maximum intensity projection (MIP) in both scan protocols. Krippendorff's alpha (α) statistical test was used to measure the agreement among raters. <h3>Results</h3> There was a high inter-rater reliability for both the acquisition protocols. Image quality of the 180 degree scans was diagnostic and there was no difficulty in identifying or measuring the fractures. <h3>Conclusion</h3> In this ex-vivo study, the 180 degree CBCT acquisition protocol was comparable to the conventional 360 degree acquisition protocol in its ability to detect and measure simulated facial fractures. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study

Foramen Magnum: A Morphometric Study in Dried Human Skulls

Introduction: The foramen magnum is the largest foramen or opening present in the base of the skull. The dimensions of the foramen magnum are clinically crucial because many vital structures are passing through it. Objective: The aim of the study was to determine the different shapes of the foramen magnum and its anteroposterior diameter and transverse diameter. Methods: This study was conducted on 32 dry human skulls of unknown age and sex. All the important parameters were studied using a vernier caliper. Results: The mean transverse diameter (TD) was found to be 27.75 ± 2.47mm (Mean ± SD) and the mean anteroposterior diameter (APD) was found to be 34.62 ± 3.58mm (Mean ± SD). The various shapes of the foramen magnum were observed. The most common shape was oval 46.9%, followed by round18.8%, tetragonal 15.6%, hexagonal 12.5%, and irregular 6.3%. Conclusions: In our study, the most common shape of the foramen magnum was oval; this can help the surgeons to perform post-cranial surgery and surgery near the foramen magnum as an oval shape indicates the narrow operative field. The study may also be helpful for anatomists for study purposes and forensic experts to determine the identity of different populations when compared to other studies.

Nonmetric Variants of Anatolian Crania: A Preliminary Study.

Analysis of nonmetric cranial variants has been essential for identifying the human population through osteologic analysis and genetic affinities. This study aimed to examine the nonmetric cranial variants to evaluate differences among sex and side correlations in Anatolian dry skulls. This study was carried out on 50 Anatolian adult dry human skulls (22 males, 28 females) with suitable features (nonfractured and/or with necessary features) out of a total of 97 dry skulls. After sex analysis, each skull was photographed from the norma frontalis, lateralis, inferior, and superior. Eleven nonmetrical cranial variants were investigated. The cranial variants and side incidences were analyzed to determine their sex differences and interside correlations. After the classification, traits were marked as "present" or "absent" on the charts. Some variants in female crania were seen more frequently than in males. Most of the variants such as the supraorbital notch, infraorbital and zygomaticofacial foramen, showed high correlations between the right and left sides. Overall, there were no statistically significant sex or side differences found in the Anatolian crania.

Accuracy of three-dimensional printed models derived from cone-beam computed tomography.

To determine the accuracy of three-dimensional (3D) printed models fabricated from cone-beam computed tomography (CBCT) scans of human mandibular dry skulls in comparison with models derived from intraoral scanner (IOS) data. Six human mandibular dry skulls were scanned by IOS and CBCT. Digital models (DMs) constructed from the IOS and CBCT data were fabricated physically using a 3D printer. The width and thickness of individual teeth and intercanine and molar widths were measured using a digital caliper. The accuracy of the DMs was compared between IOS and CBCT. Paired t-tests were used for intergroup comparisons. All intraclass correlation coefficient values for the three measurements (mesial-distal, buccal-lingual, width) exceeded 0.9. For the mandibular teeth, there were significant discrepancies in model accuracy between the IOS (average discrepancies of 0.18 ± 0.08 mm and 0.16 ± 0.12 mm for width and thickness, respectively) and CBCT (0.28 ± 0.07 mm for width, 0.37 ± 0.2 mm for thickness; P &lt; .01). Intercanine (P = .38) and molar widths (P = .41) showed no significant difference between groups. There was a statistically significant difference in the accuracy of DMs obtained from CBCT and IOS; however, this did not seem to result in any important clinical difference. CBCT could be routinely used as an orthodontic diagnostic tool and for appliance construction.

Influence of head positioning during cone-beam CT imaging on the accuracy of virtual 3D models.

Cone beam computed tomography (CBCT) images are being increasingly used to acquire three-dimensional (3D) models of the skull for additive manufacturing purposes. However, the accuracy of such models remains a challenge, especially in the orbital area. The aim of this study is to assess the impact of four different CBCT imaging positions on the accuracy of the resulting 3D models in the orbital area. An anthropomorphic head phantom was manufactured by submerging a dry human skull in silicon to mimic the soft tissue attenuation and scattering properties of the human head. The phantom was scanned on a ProMax 3D MAX CBCT scanner using 90 and 120 kV for four different field of view positions: standard; elevated; backwards tilted; and forward tilted. All CBCT images were subsequently converted into 3D models and geometrically compared with a "gold-standard" optical scan of the dry skull. Mean absolute deviations of the 3D models ranged between 0.15 ± 0.11 mm and 0.56 ± 0.28 mm. The elevated imaging position in combination with 120 kV tube voltage resulted in an improved representation of the orbital walls in the resulting 3D model without compromising the accuracy. Head positioning during CBCT imaging can influence the accuracy of the resulting 3D model. The accuracy of such models may be improved by positioning the region of interest (e.g. the orbital area) in the focal plane (Figure 2a) of the CBCT X-ray beam.

The Morphometric analysis of accessory sutural bones with an emphasis on association with parietal emissary foramina

Background: The sutural bones and fontanelle of the skull display unique morphological characters. Sutural bones are also called supernumerary bones or ossicles or Wormian bones (WB). These are irregular and develop from the independent ossification centers present along the cranial sutures. They appear on periosteal and endosteal surfaces of the skull with variations in size, number, shape, and location. In the present study, we aimed to determine the morphological characteristics of sutural bones and emphasize the significance of the same. One interesting entity of skull near the posterior fontanelle is the presence of Inca bones. Methods: The present study was done on 128 dry human skulls by a convenient sampling method. The skulls were collected from the Department of Anatomy and significant characteristic features of Inca and Wormian bones like shape, number, size and location were recorded. Results: Of the 128 dry skulls examined Wormian bones were seen in 13.2 % of skulls and Inca bones in 5.4 % of skulls. Incorporation of Wormian bones in lambdoid suture was noted in 12.5 % in sagittal suture in 0.7 % skulls respectively. The Wormian bones were found frequently on the left side (n=12) as compared to the right side (n=5). The morphometry of the accessory bones showed quadrilateral as the most common shape (n=9, 37.5 %) followed by triangular (n=4, 16.6 %). Radiological examination of all 24 skulls with accessory bones showed a zigzag pattern of accessory suture lines. Conclusions: The presence of Wormian and Inca bones can be easily confused with fractures of the related bony regions. The surgeons need to be aware of this fact in order to make a proper and accurate diagnosis. The knowledge regarding these bones is highly beneficial to the clinician, radiologist, and neurosurgeon.

MORPHOMETRIC STUDY OF THE STYLOID PROCESS AND ITS CLINICAL IMPLICATIONS

Background: Styloid process is a slender, cylindrical spur of bone fused with the inferior aspect of the temporal bone in front of the stylomastoid foramen. Present study aimed to evaluate the length, angulation, interstyloid distance and styloid ratio to highlight their possible etiological importance in clinical and surgical conditions. Interstyloid distance is used for sexual dimorphism. Excessive length and angulation of styloid process is clinically important, as it may cause Eagle's syndrome. Material And Methods: The study was done on both sides of 52 dry human skulls of unknown age and sex without any obvious deformity. Each skull was carefully examined for the presence of elongated styloid process (length&gt;30 mm). The length was measured using Vernier caliper and interstyloid distance was measured using divider. Angle of styloid process with the Reid's baseline and styloid ratio was also calculated. Results: Out of 52 skulls, elongated styloid process was observed in thirteen skulls, amongst them eight skulls (15.38%) with unilateral and ve (9.62%) with bilateral elongation. Rest of the skulls (n=39) had lengths varying from 20-30 mm. Mean angle between styloid process and Reid's baseline was 51.13°. Average interstyloid distance was 75.42 mm while 70-80 mm was the most common range. Styloid ratio varied from 3-4. Conclusions: Unilateral elongated styloid process was found more frequently as compared to bilateral. The results can be used as a baseline data for identication of male and female skull by calculating the interstyloid distance. The ndings of the present study may be of utmost importance in the examination of styloid process in patients with symptoms of stylalgia.

Morphometry of Foramen Magnum: An Anatomical Study

Introduction: The knowledge of foramen magnum dimensions is important for clinicians to highlight the malformations like Arnold Chiari malformation and Achondroplasia. Its morphometry is helpful for neurosurgeons and for forensic experts as well. Foramen magnum (FM) is a large oval opening in the occipital bone of skull that transmits part of brain stem, spinal cord and many related structures&#x0D; Aims &amp; Objectives: To determine the variations in transverse and antero posterior diameters of foramen magnum and foramen magnum index in dry skulls of adults in Pakistani population.&#x0D; Place and duration of study: The study was conducted at FMH College of Medicine &amp; Dentistry, Lahore in December 2021 on 99 dry human skulls.&#x0D; Material &amp; Methods: The foramen magnum of 99 dry skulls of human adults of unspecified gender and of unknown exact age, from the collection of Anatomy Department in FMH college of Medicine and Dentistry, Lahore, Pakistan, was examined to evaluate the dimensions of FM. Digital caliper was used to measure the antero-posterior diameter (APD) and transverse diameter (TD) of foramen magnum (FM) in dry skulls of human adults and then foramen magnum index FMI was calculated by dividing APD by TD.&#x0D; Results: The mean values of transverse and antero posterior diameters of foramen magnum in dry human skulls were found as23.18+7.68 and 29.22+7.52 respectively. The mean value of foramen magnum index was 1.30+0.22.&#x0D; Conclusion: Our study determined variations in diameters of FM and FMI in the skulls of Pakistani population. Antero posterior diameter of foramen magnum is more than its transverse diameter and majority of skulls show oval shaped FM. The results of this study may help the neurosurgeons, anthropologists, morphologists, clinical anatomists and forensic experts.

Trans-Nasion-Complex Approach for Endoscopic Modified Lothrop Procedure: Conception, Anatomy, and Technique

BackgroundThe endoscopic modified Lothrop procedure (EMLP) is an important procedure used to address frontal and anterior skull-base lesions. Two techniques were established, namely, the inside-out approach and the outside-in approach. The former technique take the frontal recess and the first olfactory filament (FOF) as key landmarks while the latter use the FOF as posterior boundary. In some cases, however, these two landmarks are not available. Therefore, we supplement the outside-in approach and named it trans-nasion-complex approach (TNCA) for EMLP that can be performed without locating these two landmarks.MethodsTwo dry human skulls were used to observe the bony nasion complex. Then, five colored silicon-injected human head specimens were dissected via TNCA for EMLP. Finally, the outcomes of patients who underwent TNCA were reviewed.ResultsThe nasion complex is an osseous complex that consists of the nasion and its adjacent structures, including the bilateral root of nasal bones, nasal process of frontal bones, anterior portion of the perpendicular plate of the ethmoid bone that connects with the inferior aspect of the nasal bones, and portions of the bilateral frontal process of the maxillary bones. Surgical landmarks for TNCA include the anterior superior portion of the nasal septum, anterior margin and axilla of the middle turbinate, frontal process of the maxilla bone, nasal process of the frontal bone and upper part of the nasal bone. These structures form a “mushroom sign” during cadaveric dissection and surgery. Twenty-one patients underwent TNCA, of whom 9 had tumors and 12 had chronic rhinosinusitis with nasal polyps (CRSwNP). None of them had major complications.ConclusionTNCA is expected to be a safe, and direct route for EMLP. Adequate understanding of the nasion complex and “mushroom sign” will be helpful to complete TNCA.

Comparison of the accuracy of linear measurements in CBCT images with different field of views

This study sought to investigate the effect of the field of view (FOV) on linear measurements of cone beam computed tomography (CBCT) images. Methods: In this in vitro study, five dry human skulls were used. After using red wax to simulate soft tissue, the skulls were scanned using Galileos CBCT scanner (Sirona, Bensheim, Germany) with exposure parameters of 85 kVp and 21 mAs and voxel size of 0.280 mm; once with FOV of 15 cm × 8 cm and once again with 15 cm × 15 cm. The measured distances were the distance between the center of the bilateral mental foramen in the axial view (MM), the distance between the alveolar crest and the mandibular inferior border in the sagittal view on the midline (CB), and the depth of the socket of the left mandibular central incisor (L1). Descriptive statistics as well as Pearson’s correlation coefficient were used for statistical analysis (α = 0.05) using SPSS software (v. 25, IBM, NY, USA). Results: The measurements obtained with small and large FOV and with the dry skull were not significantly different (p &gt; 0.05). The measurements obtained in small FOV had excellent correlation coefficient when compared with those obtained with the dry skull, with values of 0.890 for MM, 0.954 for CB, and 0.921 for L1 (p &lt; 0.001). The measurements in large FOV also had excellent correlation coefficient when compared with those on the dry skull, with values of 0.894 for MM, 0.949 for CB, and 0.902 for L1 (p &lt; 0.001). Conclusion: According to our findings, linear measurements obtained by CBCT scans in small and large FOVs were not significantly different than those on dry skulls. Since the linear measurements are accurate regardless of FOV size, selection of FOV must be based on patient factors, such as area of interest and radiation dose.

Morphometric and Morphological Variants of Pterion with its Clinical Importance in South Indian Population

Background: Pterion is a critical neuroanatomical landmark in various neurosurgical approaches, including for the placement of burr holes. In addition, it also holds significance from radiological, anthropological, and forensic point of view. Thus, we undertook the current study to investigate the prevalence of different morphological types of pterion along with their morphometric parameters from adjacent bony landmarks in the south Indian population. Methodology: A total of 64 adult dry human skulls of unknown gender and age were included for the study. All skulls were grossly normal. The types of pterions were classified on both sides based on Murphy's classification. The vertical linear distance from the center of the pterion to the zygomatic arch (PZ) and to the anterior border of the frontozygomatic suture (PF) was measured with a digital vernier caliper. Data were statistically analyzed. Results: All four varieties of pterion were noticed. The sphenoparietal variety was found as most predominant bilaterally (81%), followed by epipteric (12.5%) stellate (3.9%) and frontotemporal (2.39%). One of the epipteric varieties consists of an unusually large ossicle. Pterion was typically located 3.59 ± 0.43cm behind the fronto zygomatic suture and 3.71 ± 0.34 cm above the zygomatic arch. Conclusion: The sphenoparietal variant of pterion was predominant on both sides, followed by epipteric variety.

A STUDY ON PTERION IN ADULT DRY HUMAN SKULL BONES IN RAYALASEEMA POPULATION

Introduction: The knowledge of the variations of pterion &amp; its surgical anatomy are important for surgeons in operating the elds. This study also contribute additional information as skull bone fractures in infancy &amp; early childhood which may be associated with large inter sutural bones giving false appearance of fracture radiologically. 100 dry human skulls Materials &amp; Methods: which were obtained from the Departments of Anatomy, SVIMS - SPMCW; SV Medical college, Department of Anthropology, SV University, Tirupati; RIMS Medical college, Kadapa. Results: The sphenoparietal type of variety is seen in 71%, Frontotemporal - 20 %, Epipteric - 6 %, Stellate - 3%. The knowledge of location of pterion and its types in relation to important internal Conclusion &amp; Key Message: landmarks are really very essential for the neurosurgeon in their routine surgical approach.

A morphometric study of the foramen magnum in dry human skulls

Background: The foramen magnum is a large opening in the posterior aspect of the base of the skull, its appearance will be helpful. This study aimed to evaluate morphometrics of the foramen magnum in the dry human skull in central Indian populations, knowledge of these morphometric values is useful for the researcher. Material &amp; Methods: In this study 60 dry human skulls of unknown sex were studied in the LN Medical College, Bhopal where morphometrics of foramen magnums like anteroposterior &amp; transverse diameter and Index was observed. Results: The results obtained from the skulls along with the foramen magnum were statistically analyzed where the anteroposterior diameter is 34.41 mm, transverse diameter is 29.24mm &amp; Index is 1.17 were noted. Conclusion: Based on the different parameters of the foramen magnum values this study will be useful for clinicians, joint biomechanics, ergonomics, physical therapy &amp; rehabilitation.

Influence of sharpening filters on the detection of root fractures using low-dose cone-beam computed tomography

To evaluate the influence of sharpening filters in the detection of root fractures using low-dose cone-beam computed tomography (CBCT). Eighty-four CBCT volumes acquired at three mA levels of 28 teeth inserted in the dental socket of dry human skull were selected from a previous study. The teeth were divided into four groups according to the presence and absence of root fracture and endodontic filling. Five radiologists evaluated all CBCT volumes for the presence of root fracture with and without the application of "Sharpen 1x" and "Sharpen 2x" filters in OnDemand3D software. Area under the ROC curve (AUC), sensitivity, specificity, and inter- and intra-observer concordance were calculated and compared (α = 0.05). Sharpening filters did not lead to significant differences in AUC, sensitivity, and specificity at the three mA levels tested (p > 0.05), regardless of the presence of endodontic filling (p > 0.05). However, the significant reduction of AUC observed in CBCT volumes at 4mA without filter (p < 0.05) ceased to exist after the application of filters (p > 0.05). Sensitivity and specificity ranged from low and moderate. The use of sharpening filters can be recommended in CBCT volumes at 4mA for root fracture detection for leading to the same performance as those at 6.3 and 10mA. The presence of endodontic filling material did not influence the action of filters in the diagnosis of root fracture. Sharpening filters seem to contribute to the diagnosis of root fracture in CBCT volumes acquired with reduced radiation dose.