Morphometric analyses of atlas vertebrae-A cross sectional study (original) (raw)
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Indian Journal of Neurosurgery, 2015
The morphometry of atlas is very important for surgeries in the occipitocervical region. There are studies explicitly differing in the results concerning some key anatomic measurements, mandating an additional evaluation of anatomic landmarks of atlas. Therefore, this study was aimed to evaluate the various dimensions of the atlas quantitatively relevant for various surgeries. A total of 30 adult atlas vertebrae of Indian origin were studied. The distances were measured by digital vernier calliper. The transverse diameter and maximum anteroposterior dimension of vertebral canal of atlas had a mean of 27.31 AE 2.74 and 29.44 AE 2.54 mm, respectively. The vertebral artery groove thickness on atlas is 3.79 AE 1.08 mm on right and 4.05 AE 00.86 mm on left, respectively. The mean distance from sagittal midline to the innermost edge of the vertebral artery groove is 10.73 AE 2.92 mm on right side and 09.72 AE 2.56 mm on left side. Overall, 74% of superior articular facets were found to be oval in shape and 26% in kidney shape. On the basis of these findings, we concluded that the thickness of the vertebral artery groove is satisfactory for surgical fixation techniques and the dissection on the posterior arch of atlas can be extended to 12 mm from the midline through the posterior approach.
A morphometric study of adult human atlas vertebrae in South Gujarat population, India
The anatomy of the atlas (first cervical vertebrae, C1) exhibits complex, three-dimensional structures, showing extensive variability in morphology from other cervical vertebrae. 1 It is located at critical point close to the vital centers of the medulla oblongata which can get compressed by a dislocation of the atlanto axial complex or instability of the atlanto axial joint. 2 The atlas holds the globe of the skull and is devoid of body and spine. It has two lateral masses links by an anterior and posterior arch. Each lateral mass has superior and inferior articular facets. 1 The VAG (vertebral artery groove) is situated on the superior surface of posterior arch behind the lateral mass lodging the third part of vertebral artery. It shows transverse foramen for the vertebral artery. Dislocation of ABSTRACT Background: The atlas (C1) has undergone many structural modification and located at critical point close to the vital centres of the medulla oblongata which can get compressed by a dislocation of the atlanto axial complex or instability of the atlanto axial joint. Knowing of various dimensions of atlas vertebrae are very important for the development of instrumentation related to atlas vertebrae. Methods: In this study, total 100 dried, unbroken atlas vertebrae of unknown age and sex were evaluated in department of anatomy of medical colleges of South Gujarat. All dimensions were measured in bilateral manner using Digital Vernier Callipers with 0.01mm resolution. Results: The mean width of atlas was 71.19 mm. The mean distance between lateral margins of both transverse foramina was 55.48 mm and the inner distance was 44.77 mm. The mean for anteroposterior diameter of vertebral canal of atlas was 28.16mm and transverse diameter was 26.63 mm. The height of anterior arch was 10.21 mm and posterior arch was 8.68mm. The mean for height of facet for dens was 8.96mm and width was 9.18 mm. The mean of anteroposterior diameter of right and left superior articular facet was 20.73 mm and 20.86 mm and transverse diameter was 11.34mm and 11.39mm. The mean of anteroposterior diameter of right and left inferior articular facet was 17.89mm and 17.77mm and transverse diameter was 14.97mm and 15 mm. The mean thickness of vertebral artery groove (VAG) for right and left side was 4.15mm and 3.99mm and width was 8.26 and 8.1 mm. The length of VAG-inner edge (D1) for right and left side was 10.34mm and 10.3mm and length for outer edge (D2) was 14.93mm and 15.1mm. Conclusions: The observations of present study helps in improving understanding of various bony dimensions which could facilitate diagnosis and preoperative planning while operating close to important structures like nerve roots and the vertebral artery and will allow for more accurate modelling of South Gujarat, India.
Morphometric Anatomy of the Atlas (C1) Vertebra Among Karnataka Population in India
International Journal of Anatomy and Research, 2016
In this study one hundred dried intact human atlas vertebrae from Karnataka population were examined using direct anatomical measurements. Materials and Methods: Various dimension of the atlas vertebrae were quantitatively measured using a vernier caliper that provides accurate resolution up to 0.01 mm. The results were analyzed statistically using SPSS 12 version Results: The distance between the tips of transverse process of the atlas (atlas width TD), 72.45mm.Inner distance between medial margins of foramina transversaria, 43.88mm outer distance between the lateral margins of foramina transversaria 56.31mm.. Distance between the medial margin of the vertebral artery groove from the median plane [right-12.28 mm and left side-11.54mm]. Distance between the lateral margin of the vertebral artery groove from the median plane [right side-22.80mm and left side-22.87mm] and Thickness of the groove [right-3.68mm and left side-3.70mm] Outer anteroposterior(AP)diameter of vertebral foramen-42mm and inner AP diameter of vertebral foramen 28.51mm and transverse diameter vertebral foramen-27.39mm were noted. Superior articular facet AP diameter [right-22.33mmand left-22.25mm] Superior articular facet transverse diameter [right-8.74and left 9.57mm] Inferior articular facet AP diameter [right 18mm and left-17.81mm] and inferior articular facet transverse diameter [right 14.83mm and left 14.49mm]. Height of the anterior arch-10.02mm and posterior arch-8.91mm was recorded Conclusion: The quantitative anatomy of atlas may be helpful for neurosurgeons in avoiding and minimizing the complications such as vertebral artery injury, spinal cord injury and cranial nerve damage during the operation close to atlanto-occipital area.
COMPUTERISED TOMOGRAPHIC MORPHOMETRIC ANALYSIS OF ATLAS AND AXIS VERTEBRAE.
Aim: To study the variations in the morphological dimensions of atlas and axis vertebrae using computerised tomographic scan in Indian population , which can be extrapolated for effective future planning and meticulous surgical technique while operating in C1-C2 region for all kind of pathologies. Materials And Methods: Fifty subjects from both sexes who took computed tomographic scan of brain or cervical spine in Coimbatore medical college for any indications without any abnormality of C1 and C2 are taken for morphological analysis. Study includes patients of adult age group of more than 20 years. Various dimensions of Atlas and Axis are measured and compared with previous studies. Results: The mean value of the various dimensions of lateral mass of atlas is 15.6 mm (AP) and 12.7 mm(TR) and lateral mass of axis is 14.5 mm(AP) and 14.2 mm(TR) respectively , the average screwable thickness in the posterior aspect of C1 lateral mass is 5.4 mm on left and right side. The safe angle for trajectory of C1 lateral mass in sagittal plane is 13 0 and in axial plane is 11.9 0. Conclusion: Morphometric analysis of C1-C2 vertebra shows light on the ideal dimensions and screws to be used in our population. It also shows light on the safety angle and safety margin to avoid complications related to vertebral artery and spinal cord injury.Atlas and axis vertebrae are smaller in size but they serve anatomically and biomechanically important functions. They give maximum range of mobility without compromising stability. These two vertebrae can be affected by various diseases like congenital anomaly to trauma. Though traumatic C1C2 spine injury lead to death in certain cases,but in certain patients secondary cord injury can be prevented by proper surgical procedures and stabilisation. By analysing the computerised tomographic morphometric dimensions in our Indian population we can use optimum size screws and implants. The commonly done CVJ surgeries are occipitocervical fusion , C1C2 lateral mass fixation, odontoid screw fixation. In all the above surgeries the purchasable dimension and the quality of the bone decide the better outcome.
Study on the Morphological Variations of the Adult Human Atlas Vertebrae
International Journal of Anatomy and Research, 2016
Background: The knowledge of the anatomical variations of atlas plays very important role in neurosurgery where the surgical manipulation of the cervical spine is needed to decompress the vertebral artery as the variations of altas leads to cause cervico-basilar insufficiency. Materials and methods: Study was carried out on 50 dry adult human atlas vertebrae of unknown sex which are collected from department of Anatomy. All the specimens were observed for presence of any morphological variations. Results: Among the 50 atlases studied. The following morphological variations were observed. Incomplete foramen transversarium was observed in 2 (4%) cases. Retroarticular canals or ponticles were present in 10 (20%) of cases. Among that the complete posterior ponticles was seen in 2 (4%) atlases, one with bilateral complete retroarticular canal, and one with unilateral retroarticular canal. Incomplete posterior ponticles was seen in 8 (16%) atlases, and the incomplete lateral ponticle was seen in 1 (2%) atlas. Bilobed superior articular facet was observed in 7 (14%) of cases. Spur on the anterior arch was observed in 10 (20%) of cases. Abnormal groove around the superior articular facet on left side was observed in one atlas. Conclusion: The knowledge of the absence of costal element or incomplete formation of foramen transversarium is important for radiologists, neurologists, neurosurgeons who deal with diagnosis and treatment of head and neck region. Extreme rotation of cervical spine in an individual with retro-articular canal may lead to the compression of the third part of vertebral artery and may cause vertebro-basilar insufficiency. Hence the knowledge of the anatomical variations is very important for neurosurgeons dealing with surgical manipulation of the cervical spine to decompress the vertebral artery.
Journal of clinical and diagnostic research : JCDR, 2013
The classic variants in superior articular facets of atlas such as, variability in shape, presence of notch, constrictions, partial or complete separation of facets, and presence of pressure facets, have been reported to a limited extent in relation to ergonomics of cranio-vertebral joint. The objectives of the present study were to report the analyzed morphological features and metrical values of superior articular facets of the atlas. The morphological features which were included in this study were variability in shapes, constrictions and partial or complete separation of facets. The metrical measure included the surface area measurement of the facets. This study was carried out on 50 (100 sides) dry atlas vertebrae from the Department of Anatomy, St John's Medical College, Bangalore, India. The superior articular facets were studied for the shape and symmetry, constrictions and partial or complete separation of facets. The surface area of the facets were measured by using Im...
2015
OBJECTIVE: The morphology of the atlas vertebrae seems to be affected by the head posture, age, congenital anomalies and the skeletal growth pattern. The present study was carried out to assess the variation in the morphology of atlas vertebrae in different vertical skeletal patterns MATERIAL AND METHOD: Cone-beam computed tomography images of 45 adult subjects aged 18 to 35 years were evaluated. Subjects constituted three groups: group 1; average growth pattern; group 2; vertical growth pattern (Skeletal open bite) and group 3; horizontal growth pattern (Skeletal deep bite). Nine linear measurements were used to assess the vertebral morphology. The One way Anova and Tukey Hsd multiple comparison test were used for statistical analysis. RESULTS: The mean inner anteroposterior diameter of the atlas (C1) was significantly greater in the skeletal open bite and the skeletal deep bite group. The height of the atlas dorsal arch was lower in the skeletal open bite subjects. The mean height...
Asian Spine Journal, 2019
A cross-sectional observational study involved the analysis of computed tomography (CT) scan data from 125 Indian subjects of 18 years or older with normal imaging findings. Scans were obtained from patients with head injuries as a part of the screening process along with brain CT scans. Purpose: To establish the dimensions of lateral masses of the atlas vertebrae in normal disease-free Indian individuals. Overview of Literature: Lateral mass fixation has become the standard of care in fixation of the supra-axial cervical spine. Many studies have investigated the dimensions of lateral masses in cadaveric specimens; however, studies involving the radiological morphometric analysis of the lateral masses of the atlas vertebra in living patients are lacking. Methods: Subjects underwent craniovertebral junction CT scans during evaluations of head injury. All had normal radiology reports. The CT scans were obtained using a CT Philips Brilliance 64 machine (Philips, Amsterdam, Netherlands) with a slice thickness of 1 mm and then analyzed using Horos software ver. 2.0.2 (Horos Project, Annapolis, MD, USA) on a MacBook. Results: Lateral masses of the atlas vertebrae were found to be larger in males than females and larger on the right than the left side. The angle of permissible medialization was found to be larger on the right side. The analysis of the average dimensions indicated the conventionally described screw positions to be safe. Conclusions: The present study provides information that may help to establish standard dimensions of lateral masses of the atlas vertebrae among the normal Indian population. We demonstrate that there is no significant difference when compared with the Western population. The results presented here will be of use to clinicians as they may inform preoperative planning for lateral mass fixation surgeries.
Journal of clinical and diagnostic research : JCDR, 2015
The atlas and axis vertebra have unique shape and complex relationship with vertebral artery. Fracture of dens of axis accounts for 7-27% of all cervical spine fractures, but surgeries in these regions are highly risky because of the reported incidences of vertebral artery injury. The study was designed to measure morphometric data of human axis vertebra, of Indian origin. The different anatomical parameters on dry specimen of human axis vertebrae were established and the results were compared with other studies. Thirty intact human axis vertebrae were measured with digital vernier caliper and mini-inclinometer. Various linear and angular parameters of axis were observed. The mean distance from the midline of body to the tip of transverse process of axis was 29.32 mm on right side and 29.06mm on left side. The mean distance from the midline of body to the lateral most edge of superior articulating facet was 22.8 mm on right side and 22.6 mm on left side. The mean value of anterior a...
Indian journal of orthopaedics
The technique of intralaminar screw placement for achieving axis (C2) fixation has been recently described. The purpose of the study was to provide the morphometric and radiological measurements in Indian population and to determine the feasibility of safe translaminar screw placement in this population. To the best of our knowledge there is no study (cadaveric or radiological) done in Indian population to detect suitability of axis bone for laminar screw fixation. 38 dry axis vertebrae from adult South Indian population were subjected to morphometric measurement and CT scan analysis. Height of posterior arch, midlaminar width(bilateral) in upper 1/3(rd), middle 1/3(rd) and lower 1/3(rd) were measured using high precision Vernier Calipers. Each vertebra was subjected to a spiral CT scan (Philips brilliance 16 slice) thin 0.5 mm slices were taken and reconstruction was done in coronal and sagittal plane. Analysis was done on a CT work station. Using axial slices, sagittal cuts were r...