FREQUENCY OF CERVICAL RIBS AMONG ADULT MALES SEEKING EMPLOYMENT IN PAKISTAN ARMY.
Objective: To determine the frequency of cervical ribs among adult male population seeking employment in Pakistan army.
Study Design: Cross sectional study.
Place and Duration of Study: Department of Diagnostic Radiology, Combined Military Hospital, Hyderabad cantt from 1st October 2012 to 31st March 2014.
Material and Methods: The study was conducted on chest radiographs of 4337 adult males who reported for recruitment in Pakistan Army irrespective of ethnicity.
Results: The prevalence of cervical ribs among adult males of Pakistan was 6.11% with 4.29% bilateral, 1.13% right sided and 0.69% on left side.
Conclusion: Pakistani adult male population was observed to have 6.11% prevalence of cervical ribs, thus justifying initial screening chest radiographs of all candidates for military recruitment that can pick up all cases of cervical ribs in addition to exclusion of cardiopulmonary pathologies.
Keywords: Cervical rib, Chest radiograph, Elongated C7 transverse processes, Prevalence.
Cervical rib is a supernumerary rib which arises from the seventh cervical vertebra. It is congenital abnormality located above the normal first rib. This condition is present in approximately 1-2% of the population1,2. It is usually attached to the first rib, close to the insertion of scalenus anterior muscle (Figure-1). It may consist of a complete rib, but often the bone is present only for a variable distance, the anterior part being made of a fibrous band. Unlike a cervical rib, an elongated C7 transverse process is fused with the C7 vertebra3.
Cervical rib is usually asymptomatic and is detected as an incidental finding when a chest or neck x-ray is taken for some other purposes. The neurovascular symptoms in the upper limb were initially associated with a "cervical rib syndrome". Later on, many fibrous, bony, and muscular abnormalities were described as causes of neuromuscular compression at the thoracic outlet4,5. This has led to the term "thoracic outlet syndrome"6, still used in current publications. 10% of patients having thoracic outlet syndrome were found to have cervical rib7.
It was felt to study a section of Pakistani population to assess the usefulness of chest radiographs to detect the cervical ribs before induction in Pakistan army.
The purpose of this study is to know the prevalence of cervical ribs in Pakistani adult male population and to detect this pathology on the basis of chest radiographs.
MATERIAL AND METHODS
This cross-sectional study was conducted from 1st October 2012 to 31st March 2014 in the Diagnostic Radiology department of Combined Military Hospital, Hyderabad cantonment, Pakistan. 4337 chest radiographs of adult males, ranging from 17 years to 23 years age, were taken for induction in Pakistan army. Sample size for the study was calculated by WHO sample size formula for proportion studies8. Two experienced radiologists reviewed these radiographs. All radiographs were exposed on X-ray system 660 mA, Villa Systemi, Italy and x-ray films were processed on Fuji Automatic Film Processor, FPM-4200 Japan. All technically inadequate images were repeated to identify the presence or absence of cervical ribs. In 265 individuals with suspicion of cervical ribs, Anteroposterior projection of the cervical spine was performed to confirm the presence of cervical ribs.
Table-1: The number of cervical ribs in the study population.
Total cases studied###4337
Number of cervical rib cases###265 (6.11%)
Bilateral cervical rib###186 cases (4.29%
Right side###49 cases (1.13%)
Left side###30 cases (0.69%)
The following criteria to identify the presence of a cervical rib on chest radiographs were used:
1. The rib must abut the seventh cervical vertebral transverse process, which is seen to project horizontally or caudally from the spine (figure-2).
2. It must have no connection with the manubrium sterni, thus distinguishing a cervical rib from rudimentary first rib.
3. The cervical rib must be separate from, but articulate with, the transverse process of C7. If fused with the vertebra, it was classed as an elongated transverse process. Elongated C7 transverse processes were also noted which were classified as any C7 transverse process longer than the T1 transverse process.
In our study, 4337 cases were examined for cervical rib. Median age was 19 years with age range of 17 years to 23 years. 265 cases were positive with an overall prevalence of 6.11%. Of the 265 individuals with cervical ribs, 30 were on the left, 49 on the right and 186 were bilateral (table-1). A total of 451 cervical ribs were found in our 265 cases. Of the fifty-two individuals with long transverse processes giving an overall prevalence of 1.20%, thirty-five were bilateral, ten on right side and seven on left side. A total of 87 elongated C7 transverse processes were found in our 52 cases.
We found overall prevalence rate of cervical rib to be 6.11% which is too high as compared to 0.42% in the London study conducted on 1352 males9, 0.49% with bilateral predominance in the Indian study conducted on 7,272 males10, and 1.36% in central India on 2500 males11.
Erken et al reported a prevalence of 6.2% for cervical rib in a population sample from Turkey12. Rakan F Bokhari et al in 2012 claimed a higher prevalence of cervical rib and elongated C7 transverse processes as 3.4% and 23% respectively, in a population in Jeddah, Saudi Arabia13. Two recent studies in Nigeria, first using anteroposterior cervical spine radiographs and second using posteroanterior chest radiographs, found 0.4% prevalence of cervical ribs in 245 males and 0.6% prevalence of cervical ribs in 617 males respectively14,15.
"Radiographic evaluation of cervical spine" at Wah, Pakistan in year 2010 demonstrated 3.9% prevalence of cervical ribs in 1000 cases of mixed ages and both sexes16. The prevalence rate of enlarged C7 transverse processes was 1.20%, <2.21% noted for London population and 23% in a population in Jeddah, Saudi Arabia.
The reason for higher prevalence rate of cervical ribs in our study can be related to use of chest as well as cervical spine radiographs. There was no chance of missing rudimentary cervical ribs or misinterpreting elongated C7 transverse processes as rudimentary cervical ribs; as all cases with suspicious cervical ribs and enlarged C7 transverse processes were subjected to AP projection of cervical spine which confirmed the presence of both entities in 100% cases. Study by Guelkon et al used cervical spine radiographs with additional oblique projections; even then their prevalence rate was <our study17.
The use of CT imaging did not appear to increase the prevalence of cervical ribs, which was 1.4% in male population18. Cervical ribs were identified on 1.2% of MRI examinations, lower than CT, but MRI may equivalent anatomic explanation for patients' symptoms19. MRI and CT scans can identify cervical root injury from degenerative spurs, disc herniation, or other causes. MRI can identify distortion or displacement of the plexus in the thoracic outlet or supraclavicular space, usually from fibrous bands but also from clavicular abnormality. Doppler ultrasound and angiography are only useful in the presence of vascular clinical signs20.
Difference of prevalence of cervical ribs between different ethnic populations may suggest true differences in the rate of cervical ribs between populations. This suggests that genetic or environmental factors may contribute to the formation of cervical ribs. Our data includes the Hyderabad division of Sindh province which can be considered as cosmopolitan region representing Pakistani population; as it contains mixture of local Sindhis, and migrants from India and other parts of Pakistan with 5% Christians and 2% Hindu communities.
Our study found high prevalence rate of 6.11% of cervical ribs in Pakistani population but low prevalence rate of elongated C7 transverse processes of 1.20%.
The authors express gratitude to Brigadier Aamir Ijaz (Head of Academics, AFIP Rawalpindi) for assistance in improvement of manuscript.
CONFLICT OF INTEREST
This study has no conflict of interest to declare by any author.
1. Moore K.L. Clinically Oriented Anatomy 6th Ed. Lippincott Williams and Wilkins. 2010; 460.
2. Galis F. "Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes, and cancer". J. Exp. Zool.1999; 285 (1): 19-26.
3. Ebite L.E, Igbigbi P.S, Chisi J.E. Prevalence of true cervical rib in adult Malawian population. J. Anat Sci. 2007; 1(1) 7-9.
4. Roos DB. Congenital anomalies associated with thoracic outlet syndrome. Anatomy, symptoms, diagnosis, and treatment. Am J Surg. 1976; 132:771-778.
5. Makhoul RG, Machleder HI. Developmental anomalies at the thoracic outlet: An analysis of 200 consecutive cases. J Vasc Surg. 1992; 16:534-545.
6. Roos DB, Annest SJ, Brantigan CO. Historical and anatomic perspectives on thoracic outlet syndrome. Chest Surg Clin N Am. 1999; 9:713-723.
7. Leffert RD. Thoracic outlet syndromes. Hand Clin. May 1992; 8(2):285-97.
8. STEPS Sample Size Calculator and Sampling Spreadsheet [Online] cited on 15 Aug 2014. Available at: http: //www. who.int/ chp/steps /resources/sampling/en/.
9. Brewin J., Hill M., Ellis H. Department of Anatomy, Guy's King's and St. Thomas School of Biomedical Sciences London, United Kingdom. Prevalence of cervical ribs in a London population. Clinical Anatomy. April 2009; 22 (3): 331-6.
10. Anima G, Gupta D.P., Saxena D.K, Gupta R.P. Cervical Rib: It's Prevalence in Indian Population around Lucknow (UP). J of Anatomical Society of India. 2012; 61(2): 189-191.
11. DK Sharma, Vishnudutt, Vandana Sharma, Mrithunjay Rathore. Prevalence of 'Cervical Rib' and its association with gender, body side, handedness and other thoracic bony anomalies in a population of Central India. Indian Journal of Basic and Applied Medical Research. March 2014; 3 (2): 593-597.
12. Erken E, Ozer HT, Gulek B, Durgun B. The association between cervical rib and sacralization. Spine (Phila Pa 1976). 2002; 27: 1659-1664.
13. Rakan F Bokhari, Mohammad J Al-Sayyad, Saleh S Baeesa. Prevalence of cervical ribs and elongated transverse processes in Saudi Arabia, Saudi medical journal. 2012; 33(1):66-9.
14. Ebeye O Abimbola, Apare A Willido. Prevalence of Cervical Ribs in a Nigeria population. IOSR Journal of Dental and Medical Sciences. Feb. 2014; 13 (2):05-07.
15. Ani CC, Adegbe EO, Ameadaji M, Gabkwet A. Cervical Rib Variant in a Nigerian Population. Jos Journal of Medicine. 2012; 6 (1): 60-62.
16. Salam A, Ahmed MU, Kohistani TA. Radiographic evaluation of cervical spine. RMJ. 2010; 35(2): 152-155.
17. Gulekon IN, Barut C, Turgut HB. The prevalence of cervical rib in Anatolian population. Gazi Med J. 1999; 10:149-152.
18. Viertel VG, Intrapiromkul J, Maluf F, Patel NV, Zheng W, Alluwaimi F et al. Cervical Ribs: A Common Variant Overlooked in CT Imaging. AJNR Am J Neuroradiol. Dec 2012; 33(11): 2191-4.
19. Walden MJ, Adin ME, Visagan R, Viertel VG, Intrapiromkul J, Maluf F et al. Cervical ribs: identification on MRI and clinical relevance. Clin Imaging. 2013; 37(5):938-41.
20. Laulan J, Fouquet B, Rodaix C, Jauffret P, Roquelaure Y, Descatha A. Thoracic outlet syndrome: definition, etiological factors, diagnosis, management and occupational impact. 2011; 21(3):366-73.
|Printer friendly Cite/link Email Feedback|
|Publication:||Pakistan Armed Forces Medical Journal|
|Date:||Jun 30, 2016|
|Previous Article:||SELF-CARE AND DIETARY PATTERNS AMONG DIABETES MELLITUS PATIENTS IN RAWALPINDI.|
|Next Article:||DISTRIBUTION OF BLOOD TYPE AND Rh FACTOR AMONG BLOOD DONORS OF LAHORE.|