# A morphometric study of atlas & axis vertebrae in Rajasthan population.

INTRODUCTION: The cervical spine provides higher level of flexibility and motion as compared to the lumber and thoracic spine regions. These characteristics can be attributed to the anatomy of the specific cervical vertebrae. Knowing the dimensions of the vertebral elements is very important for the development of instrumentation related to cervical spine. Ethnic variations have been reported in these dimensions. Instrumentation of the vertebral column is used for the treatment of cervical instability as well as for the decompression of neural structures. These studies have used diverse techniques to obtain vertebral column measurements and these parameters can be used as reference values for evaluating various clinical conditions in the cervical spine. The insertion of such instrumentation must respect the anatomic limits of the region. There are seven cervical vertebrae out of which the first, second and seventh are atypical. First and second cervical vertebrae is called atlas and axis respectively. Aim of the present study was to evaluate the metrical details of first and second cervical vertebrae to correct the instability of atlantoaxial joint, and to analyze the morphological features to understand the ergonomics of the craniovertebral joints.MATERIAL AND METHODS: This study was conducted in the Department of Anatomy S. M. S. Medical college jaipur. Total 150 (75 atlas and 75 axis) cervical vertebrae were evaluated. All of the vertebrae which were included in the study were in good condition, without trauma or infection or neoplastic disease and without apparent disease or deformities. All the measurements have taken in bilateral manner using Digital Vernier Calipers with. 01 precision.

Following parameters of atlas were Measured:

A. Width of Atlas--it is measured as the distance between the tips of two transverse process of first cervical vertebrae

B. Vertebral Foramina Diameter--Transverse diameter and Anterioposterior (A-P) Diameter.

a. Transverse Diameter of vertebral canal--it is measured along frontal plane passing through the canals midpoint.

b. Anterioposterior Diameter of vertebral canal--it is measured along midsaggital plane passing through canals widest point.

c. Height of anterior arch--it is measured in the midline from its superior border to inferior border.

C. Height of posterior arch--it is measured in the midline posterior part as distance between superior and inferior border.

D. Superior articular facet--Transverse and anterioposterio (A-P) diameter of right and left side of superior articular facets are measured.

E. Length /A-P Diameter--it is measured from inferior border to superior vertex of process.

F. Width /Transverse Diameter--it is marked as length of transverse Diameter of the process.

G. Inferior articular facet--Transverse and Anterioposterior (A-P) Diameter of right and left side of inferior articular facet are measured.

a. Length/A-P Diameter--it is measured from inferior border to superior vertex of the process.

b. Width--it is marked as length of transverse Diameter of the process.

Measurements of Second cervical vertebra (Axis):

A. Width of dens axis--it is measured as the widest diameter of dens axis on coronal plane.

B. Height of dens--measured as distance from the tip of dens axis to horizontal line which arbitrarily passed superior to superior articular facet of axis.

C. Length of inferior articular process--it is measured as the anterioposterior diameter of inferior articular facet.

D. Width of inferior articular process--it is measured as the transverse diameter of facet.

E. Length of superior articular facet--it is measured as the anterioposterior Diameter of superior articular facet.

F. Width of superior articular process--it is marked as the transverse diameter of superior articular facet.

G. Anterioposterior diameter of vertebral foramina--Measured along midsaggital plane passing through the canals widest point.

H. Transverse Diameter of vertebral foramina--it is measured along frontal plane passing through the canals midpoint.

OBSERVATION TABLES:

Table 1: Descriptive Mean and S.D. of first cervical vertebrae (Atlas) Descriptive Statistics of first cervical vertebrae (Atlas) Observed parameters N Mean WIDTH OF ATLAS 75 69.028667 A-P DIAMETER OF VERTEBRAL CANAL 75 25.5230666 TRANSVERSE DIAMETER OF VERTEBRAL CANAL 75 21.9852 HEIGHT OF ANTERIOR ARCH 75 7.4206667 HEIGHT OF POSTERIOR ARCH 75 5.3452 A-P DIAMETER OF Rt. SUP. ARTICULAR FACET 75 17.7999 A-P DIAMETER OF Lt. SUP. ARTICULAR FACET 75 18.2901 TRANSVERSE DIAMETER OF Rt. Sup. ARTICULAR FACET 75 7.80747 TRANSVERSE DIAMETER OF Lt. SUP. ARTICULAR FACET 75 8.3284 A-P DIAMEYER OF Lt INF. ARTICULAR FACET 75 14.2653 A-P DIAMETER OF Lt INF. ARTICULAR FACET 75 14.8344 TRANSVERSE DIAMETER OF Rt. INF. ARTICULAR FACET 75 10.416 TRANSVERSE DIAMETER OF Lt. INF. ARTICULAR FACET 75 10.6573 Observed parameters Std. Deviation WIDTH OF ATLAS 3.3986501 A-P DIAMETER OF VERTEBRAL CANAL 1.882662236 TRANSVERSE DIAMETER OF VERTEBRAL CANAL 1.839694 HEIGHT OF ANTERIOR ARCH 1.1504727 HEIGHT OF POSTERIOR ARCH 0.833724 A-P DIAMETER OF Rt. SUP. ARTICULAR FACET 2.03045 A-P DIAMETER OF Lt. SUP. ARTICULAR FACET 2.50672 TRANSVERSE DIAMETER OF Rt. Sup. ARTICULAR FACET 1.2847 TRANSVERSE DIAMETER OF Lt. SUP. ARTICULAR FACET 1.5433 A-P DIAMEYER OF Lt INF. ARTICULAR FACET 1.77378 A-P DIAMETER OF Lt INF. ARTICULAR FACET 2.16713 TRANSVERSE DIAMETER OF Rt. INF. ARTICULAR FACET 1.411362 TRANSVERSE DIAMETER OF Lt. INF. ARTICULAR FACET 1.479858 Observed parameters Range WIDTH OF ATLAS 74.75-60.6 A-P DIAMETER OF VERTEBRAL CANAL 32.1-20.5 TRANSVERSE DIAMETER OF VERTEBRAL CANAL 27.5-18.25 HEIGHT OF ANTERIOR ARCH 10.85-5.3 HEIGHT OF POSTERIOR ARCH 8.85-3.25 A-P DIAMETER OF Rt. SUP. ARTICULAR FACET 21.7512.75 A-P DIAMETER OF Lt. SUP. ARTICULAR FACET 25-11.75 TRANSVERSE DIAMETER OF Rt. Sup. ARTICULAR FACET 11.5-5.5 TRANSVERSE DIAMETER OF Lt. SUP. ARTICULAR FACET 11.6-4.15 A-P DIAMEYER OF Lt INF. ARTICULAR FACET 20.8511.75 A-P DIAMETER OF Lt INF. ARTICULAR FACET 20.2-10.5 TRANSVERSE DIAMETER OF Rt. INF. ARTICULAR FACET 13.85-6.8 TRANSVERSE DIAMETER OF Lt. INF. ARTICULAR FACET 13.95-7.85 Table 2: Descriptive Mean and S.D. of second cervical vertebrae (Axis) Observed Parameters N Mean WIDTH OF DENS AXIS 75 6.6413333 LENGTH OF DENS AXIS 75 12.9492 DISTANCE FROM TIP OF TRANSVERSE 75 25.42266667 PROCESS TO MIDLINE VERTEBRAL CANAL A-P DIAMETER 75 16.4818667 VERTEBRAL CANAL TRANSVERSE 75 19.81213333 DIAMETER A-P DIAMETER OF Rt. SUP. 75 14.65027 ARTICULAR FACET A-P DIAMETER OF Lt SUP. 75 14.66133 ARTICULAR FACET TRANSVERSE DIAMETER OF Rt 75 13.34733 SUP.ARTICULAR FACET TRANSVERSE DIAMETER OF Lt INF. 75 13.37733 ARTICULAR FACET A-P DIAMETER OF Rt. INF. 75 9.128 ARTICULAR FACET A-P DIAMETER OF Lt. INF. 75 9.033867 ARTICULAR FACET TRANSVERSE DIAMETER OF Rt INF. 75 6.8592 ARTICULAR FACET TANSVERSE DIAMETR OF Lt. INF. 75 6.923867 ARTICULAR FACET Observed Parameters Std. Deviation Range WIDTH OF DENS AXIS 0.99224606 8.7-5.1 LENGTH OF DENS AXIS 1.3951642 16.1-10.52 DISTANCE FROM TIP OF TRANSVERSE 2.092570728 31.8-22 PROCESS TO MIDLINE VERTEBRAL CANAL A-P DIAMETER 1.12344871 18.75-13.7 VERTEBRAL CANAL TRANSVERSE 1.177004091 22.5-16.5 DIAMETER A-P DIAMETER OF Rt. SUP. 1.442236 17-12.37 ARTICULAR FACET A-P DIAMETER OF Lt SUP. 1.708897 18.6-11.8 ARTICULAR FACET TRANSVERSE DIAMETER OF Rt 1.50453 17.5-10.5 SUP.ARTICULAR FACET TRANSVERSE DIAMETER OF Lt INF. 1.646686 17-9.5 ARTICULAR FACET A-P DIAMETER OF Rt. INF. 1.618948 13-4.5 ARTICULAR FACET A-P DIAMETER OF Lt. INF. 1.673117 12.8-5.5 ARTICULAR FACET TRANSVERSE DIAMETER OF Rt INF. 1.322132 9.9-4.25 ARTICULAR FACET TANSVERSE DIAMETR OF Lt. INF. 1.429014 10.8-4.5 ARTICULAR FACET

RESULT AND DISCUSSION: Atlas supports the skull and is uniquely positioned in the atlantoaxial complex. As new surgical techniques and instruments for the treatment of unstable cervical spine continue to evolve, detailed knowledge about this bone become more essential. Calculated mean value for width of atlas in our study was 69.03 mm. Max and minimum value was observed as 74.75 and 60.6mm respectively. In previous studies sengul and Kogiglu et al calculated as 74.6mm. Lang et al calculate it as 78.2 mm. Shilpa N Gosavi et al in 2012 calculated the mean value for width of atlas 69.37 mm and maximum and minimum values were 85.02 and 56.36 respectively. T. Sharma observed the mean value of Atlas width as 77 and 68 mm for male and female Punjabi population. In present study the observed mean value for anterioposterior diameter of vertebral canal of atlas is 25.52 mm. Maximum and minimum value were evaluated as 32.1 and 20.5 mm. Shilpa N Gosavi in 2012 measured the maximum Anterioposterior Diameter as27.89 and minimum diameter was25.66 mm. Sengul et al in 2006 observed the maximum and minimum Anterioposterior diameter 46.2 and 31.4 mm respectively. H. R. Blackley observed the mean anterioposterior diameter for Chinese male and female through radiographs as 15.55-28.0 and 16.0-26.0 mm respectively. Stanley measured the mean Anterioposterior diameter of vertebral canal of first cervical vertebrae as 21.40 mm through computer tomography. In present study the mean calculated value for transverse diameter of vertebral canal of Atlas is 21.985 mm. maximum and minimum observed value for transverse Diameter is 27.5 and 18.25 mm. Sengul et al in 2006 observed the mean value of transverse diameter as 28.7mm, maximum and minimum value were 33.5 and 25.2 mm respectively. Heggeness et al observed the mean transverse diameter of Atlas 32 mm. Stanley et by CT observed the mean transverse diameter of vertebral canal as28.20 mm. Calculated mean value for height of anterior arch was7.42 mm. observed maximum and minimum value were10.85 and 5.3 mm. for posterior arch height is calculated 5.3 mm. for posterior arch maximum observed value was 8.85 and minimum was 3.25mm. Shilpa N gosavi et al observed the height of anterior and posterior arch as10.33 and 8.61 mm respectively. Observed minimum and maximum value for anterior arch height was 16.19 and 6.88 mm, for posterior arch maximum value is 14.11 mm and minimum was 4.88 mm. The mean value of Anterioposterior diameter of Rt. and Lt. Superior articular facet was calculated 17.99 and18.29 mm respectively. Maximum and minimum value of A-P diameter of superior articular process was measured as 21.75 [+ or -] 2.03 and 12.75 [+ or -] 2.50 respectively. Calculated mean transverse diameter of Rt. and Lt. Superior articular process was7.81 [+ or -] 1.28 and 8.33 [+ or -] 1.54 mm. Gupta et al observed the mean value of A-P superior articular facet in Indian population as 19.73 mm for both side. Kandziora et al calculated the mean value of A-P diameter of superior articular facet 25.3 [+ or -] 2.22 mm in Korian population. In our present study the calculated mean value of transverse diameter of superior articular facet was evaluated as 17.99 [+ or -] 2.03 mm and 18.29 [+ or -] 2.50 mm respectively. Koing et al observed the mean value of transverse diameter of superior articular facet of right and left side as 11.6 [+ or -] 2.0 and 11.2 [+ or -] 1.5 mm in German population. Shilpa N gosavi evaluate the mean value of transverse diameter of superior articular facet 10.36 [+ or -] 1.72 mm and 10.47 [+ or -] 1.61 mm respectively.

In our present study anterioposterior diameter of inferior articular facet of atlas was calculated as 13.35 [+ or -] 1.50mm and 13.38 [+ or -] 1.65 respectively for right and left side. Gupta et al calculated the mean value of it as 15.6 mm for both right and left side. Cattrysse et al calculated the mean value of A-P diameter of right and left inferior articular facet 17.0 [+ or -] 1.8 and 16.6 [+ or -] 1.6 mm respectively in Belgian population. Kaur et al evaluate the mean value of A-P diameter of Rt. and Lt. Side inferior articular facet as 17.54 [+ or -] 1.50 and 17.70 [+ or -] 1.60 mm. In present study transverse diameter of inferior articular facet was observed as 6.86 [+ or -] 1.32 mm and 6.92 [+ or -] 1.44 mm respectively. Shilpa N Gosavi calculated this 7.13 [+ or -] 1.0 and 7.4 [+ or -] 1.67 mm for right and left inferior articular facet. Sengul et al calculated the mean value as 14.6 [+ or -] 2.5 mm for both side inferior articular facets in Turkish population.

The distinguish feature of axis is dens or odontoid process projecting superiorly from its body. Odentoid process is hold in position against the posterior aspect of the anterior arch of atlas by the transverse ligament. Measurements of axis have been summarized as mean and standard deviation.--In present study calculated mean value for width of dens was observed 6.64 [+ or -] 0.992mm. Maximum and minimum values were observed as 8.7 and 5.1 mm respectively. Mean value for Length of dens was evaluated12.95 mm. Maximum and minimum values for length of dens were observed as 16.1 and 10.52 mm. T Sharma et al in 2008 studied the dimensions of axis in Punjabi population and observed the mean value of length of dens axis as 18.4 and15.5 mm for male and female. Range of dens length was seen 17.9-19.4 mm, which is higher than values observed in our study. Tulsi et al in 1978 observed the mean value of dens length in Australian population 14.4 and 13.7 mm for male and female respectively. Range varies from 11.0-18.0 mm. Calculated mean value for A-P diameter of vertebral canal was observed 16.48 [+ or -] 1.12 mm. Range varies from 18.75-13.7 mm. Mean value for transverse diameter was calculated as 19.81 [+ or -] 1.18 mm. Sengul et al calculated the mean value of A-P diameter of vertebral canals of axis 20.8 mm and transverse Diameter was 24.5 mm in Turkish population. Range variation for A-P diameter was11.5-28.9mm and range for transverse diameter varies 24.7-28.3 mm which is higher than our values. Singh et al in 2013 calculated the mean A-P diameter of vertebral canal for C2 vertebrae by plane radiograph in eastern region of Nepal as19.89 mm and 19.67 mm for male and female respectively. Calculated A-P diameter of Rt. Superior articular facet of axis was 14.65 [+ or -] 1.44 mm and for Lt. It was calculated 14.65 [+ or -] 1.44 mm. Koing et al calculated the mean value of A-P diameter of superior articular facet of axis as 19.1 [+ or -] 2.1 and 18.7 [+ or -] 2.2 in German population. Cattrysse et al observed the mean value of A-P diameter of superior articular facet of axis vertebrae in Belgian population as 17.9 [+ or -] 1.8 and 17.7 [+ or -] 1.4 mm.

Mean values of transverse diameter of superior articular process were calculated 13.35 [+ or -] 1.50 and 13.38 [+ or -] 1.65 mm for right and left side respectively. Kandziora et al in Europian population observed the mean value of transverse diameter of superior articular facet as 16.6 [+ or -] 1.25. Sengul et al in Turkish population calculated it 14.1 [+ or -] 1.6 and 14.0 [+ or -] 1.5 mm for right and left side.

Mean value for A-P diameter of inferior articular facet of axis was calculated 9.13 [+ or -] 1.62 and 9.03 [+ or -] 1.67 mm for right and left side respectively. Maximum and minimum values for right side were observed as 13 and 4.5 mm and 12.8 and 5.5 mm for left side. Gomez-Olivencia et al in Spanish population observed the A-P diameter of inferior articular facet of axis 10.1 [+ or -] 1.4 for both side. Kaur et al observed the mean value of A-P diameter of inferior articular facet as 11.54 [+ or -] 1.66 and 12.14 [+ or -] 1.58 mm in Indian population.

Observed mean value for transverse diameter of inferior articular process of axis is 6.86 and 6.92 mm for right and left side respectively. Sengul et al observed the mean value of transverse diameter of inferior articular facet in Turkish population 9.6 [+ or -] 1.7 and 9.4 [+ or -] 1.5 mm for right and left side. Kaur et al observed the same parameter as 9.23 [+ or -] 1.70 and 9.41 [+ or -] 1.61 mm for right and left side respectively.

CONCLUSION: Morphometric data's can provide more accurate measurements of anatomical elements of cervical spine that could facilitate diagnosis and preoperative planning, thus avoiding possible trauma during tissue dissection and instrument application. The first two vertebrae are particularly unique and allow the movement of the head. The results of this investigation will allow for more accurate modeling of this region, in order to assist in the development of improved spinal implants as well as more efficient surgical device placement techniques. Additionally these statistics will lead to better understanding of cervical spine functionality and its susceptibility to failure. The complex structure of the cranio- vertebral junction plays a significance role in global kinematics of the cervical spine to maintain head in upright posture. Instability at the atlas and axis requires internal fixation for immediate stability and for long term immobility. These surgical techniques and instruments continue to evolve. Transarticular screw fixation has become one of the primary treatment options for C1-C2 instability.

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DOI: 10.14260/jemds/2014/4092

BIBLIOGRAPHY:

1. S Singh, M Balakrishnan, Morphometric study of cervical spine vertebrae in eastern region Nepalese population: Health Renaissance 2013; 11 (3): 224-228.

2. T Sharma, H Rai, JS Kulla, M Lalit, Genderwise morphometric database from adult Atlas and axis. JPAFMAT 2008; 8 (2). ISSN 0972-5687.

3. Heggeness MH, Doherty BJ, The quantitative anatomy of the atlas. Spine.1994; 19: 2497-500.

4. Cattrysse E, Provyn S, Gagey O, Kool P, Clarys JP, Roy PV. In vitro three dimensional morphometry of the lateral atlantoaxial articular surfaces.Spine.2008; 33 (14): 1503-8.

5. Sengul G, Kodiglu HH, Morphometric anatomy of Atlas and axis vertebrae. Turkish Neurosurgery: 2006; 16 (2): 69-76.

6. Kayalioglu G, Erturk, M. Varol, Morphometry of the cervical pedicles as a guide for transpedicular screw fixation. Neuol. Med. Chir, 2007, 47: 102-8.

7. Kaur Jasveen, Grewal Harsimran, Singh Poonam, Kumar Ajay, Morphometric study of the articular facets of Atlas and axis vertebrae: Unique Journal of Medical and Dental Sciences 2014, 02 (02): Page 83-89.

8. Shilpa N Gosavi,, Vatsalaswamy P, Morphometric Study of the Atlas Vertebra using Manual Method: Malaysian Orthopaedic Journal 2012 Volume 6 No 3.

9. Kandziora F, Schulze-Stahl N, Khodadadyan Klostermann C, Schroder R, Mittlmeier T. Screw placement in transoral atlantoaxial plate systems: an anatomical study. J Neurosurg (Spine1). 2001 July; 95: 80-7.

10. Gomez-Olivencia A, Carretero JM, Arsuaga JL, Rodriguez-Garcia L, Garcia-Gonzalez R, Martinez I. Metric and morphological study of the upper cervical spine from Sima de los Huesos site (Sierra de correlation with degenerative changes in 30 cadaveric specimens. J Neurosurg Spine.2005; 3: 379-85.

11. Cattrysse E, Provyn S, Gagey O, Kool P, Clarys JP, Roy PV. In vitro three dimensional morphometry of the lateral atlantoaxial articularsurfaces. Spine.2008; 33 (14): 1503-8.

Rekha Parashar (1), Sangita Chauhan (2), Dhiraj Saxena (3), Saroj Lata Meena (4)

PARTICULARS OF CONTRIBUTORS:

(1.) ph. D. Student, Department of Anatomy, SMS Medical College, Jaipur, Rajasthan.

(2.) Professor & HOD, Department of Anatomy, SMS Medical College, Jaipur, Rajasthan.

(3.) Professor, Department of Anatomy, SMS Medical College, Jaipur, Rajasthan.

(4.) Demonstrator, Department of Anatomy, SMS Medical College, Jaipur, Rajasthan.

NAME ADDRESS EMAIL ID OF THE CORRESPONDING AUTHOR:

Dr. Rekha Parashar, # 918, Shanti Nagar, Opp. Durgapura Railway Station, Jaipur-302018, Rajasthan.

E-mail: lineparashar1985@gmail.com

Date of Submission: 05/12/2014.

Date of Peer Review: 06/12/2014.

Date of Acceptance: 18/12/2014.

Date of Publishing: 26/12/2014.

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Title Annotation: | ORIGINAL ARTICLE; Rajasthan, India |
---|---|

Author: | Parashar, Rekha; Chauhan, Sangita; Saxena, Dhiraj; Meena, Saroj Lata |

Publication: | Journal of Evolution of Medical and Dental Sciences |

Article Type: | Report |

Geographic Code: | 9INDI |

Date: | Dec 29, 2014 |

Words: | 3367 |

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