Morphometric Anatomy of the Atlas (C1) Vertebra Among Karnataka Population in India (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 analyses of atlas vertebrae-A cross sectional study
Introduction: Knowledge about morphometric measurements related to atlas vertebra are important for neurologists, neurosurgeons and head and neck surgeons who deal with traumatic or non-traumatic conditions which may lead to altanto-axial and atlanto-occipital instability. The aim of the present study was to assess the various parameters on the atlas vertebra which can help to determine the safe sites for the different surgical approaches. Materials and Methods: Study was carried out on 50 dry south Indian adult human atlas vertebrae of unknown sex which were collected from the department of anatomy. Eleven parameters were measured for each atlas using a digital vernier caliper. Results: Range, mean and standard deviations were measured and recorded and bilateral symmetry was observed. Conclusion: The parameters measured in the present study may help surgeons in avoiding and reducing complications such as vertebral artery injury, spinal cord injury during the surgical corrections of atlanto axial or atlanto occipital instability.
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...
A Morphological Study of Ponticuli of the Human Atlas Vertebrae and Its Clinical Significance
International Journal of Anatomy and Research, 2015
BACKGROUND: The first cervical vertebra, atlas plays a vital role in the movement of skull & neck. The anatomy of atlas is complex due to its three dimensional structure. There is a groove on superior surface of posterior arch of atlas for passage of 3 rd part of vertebral artery and first cervical spinal nerve (suboccipital nerve). Sometimes the oblique ligament of atlas which is present at the lower border of posterior atlanto-occipital membrane may ossify and convert this groove into a foramen. This foramen may be complete or incomplete, In some cases a bony bridge also extends from lateral masses of atlas to the posterior root of transverse process and form an additional foramen through which vertebral artery travels. The vertebral artery is prone to compression in its entire course between foramen transversarium and foramen magnum during extreme rotation movement of head & neck. This condition may be aggravated by the presence of these ponticuli & results in compromised blood flow and causes vertebrobasilar insufficiency presenting with dizziness, fainting, vertigo, transient diplopia & various neurological disturbances. MATERIALS & METHODS: The present study was carried out on 118 (Male-62, Female-56) dried fully ossified adult human atlas of known sex for the presence of complete or incomplete ring for vertebral artery i.e. different ponticuli on the superior surface of the atlas vertebra. RESULTS: We observed 21.17% cases of ponticulus posterior in which 7.62% specimens had complete ring while 13.55% specimens had incomplete ring & ponticulus lateralis was reported only in 5.93% cases (unilateral: 2.54% & bilateral: 3.39%). Incidence of ponticulus posterior as well as lateralis were more common in male as compared to female. Complete ponticulus posterior was more common in right side, while incomplete ponticulus posterior as well as ponticulus lateralis were more commonly bilaterally. CONCLUSION: As indicated by our study, ponticulus posterior as well as lateralis are not so rare anomaly in the population of Bihar. So, the detail knowledge about these variations is very helpful to the neurophysicians, neurosurgeons, orthopedicians & otolaryngologists who faces regularly the patients complaining about the symptoms of vertebrobasilar insufficiency. These informations are also important for the spine surgeons to prevent vascular complications during spinal surgeries especially in those patients who required screw placements in the lateral mass of atlas.
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...
Journal of Fatima Jinnah Medical University
Background: Among the cervical vertebrae, atlas is known to have many variations, posterior ponticle being the commonest. It may completely or incompletely covers the groove of vertebral artery leading to ischemia of posterior circulation. Therefore, vertebral artery is at greater risk of injury during neurological and spinal surgeries. Prevalence of posterior ponticles varies widely among different populations, for instance in Turkish population it was 10.8%, in American 22.1%, Kenyan 14.7%, Brazilian and Indian 16.7%. The prevalence of lateral ponticle in Kenyan population was reported to be 3.9% and in Indians it was 2%. However, the data regarding the prevalence of these ponticles is largely lacking in Pakistan. Therefore, this research was designed to determine the prevalence of posterior and lateral ponticle in atlas vertebrae of Pakistani population. Materials and methods: A total of 47 human atlas vertebrae of unknown age and gender from bone bank of Department of Anatomy Fa...
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.