Investigations of upper crossed syndrome’s characteristics in dental students

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Thanaporn Srijessadarak
Daraporn Sae-Lee
Aatit Paungmali
lugkana mato
sawitri wanpen
Sauwanan Bumrerraj
Yodchai Boonprakob


Background: From biomechanical dimension, working position of dentist is a prolonged trunk forward bending and forward shoulder posture during clinical practice. It can be assumed that dentists have a high risk of neck or shoulder pain, and upper thoracic pain. These conditions may lead to upper crossed syndrome (UCS) which is consisted of pectoral and neck extensor muscles tightness with scapular and neck flexor muscles weakness.

Objectives: To determine craniovertebral angle, pectoralis minor length test, craniocervical flexion test, and scapular muscles strength tests in dental students.

Materials and methods: A cross-sectional study was conducted in 220 dental students in 1-6 grades at KhonKaen University. The participants were received physical examination. Length testing of neck extensor muscles was measured by craniovertebral angle, length testing of pectoral muscles was measured by pectoralis minor length test, strength of neck flexor muscles was measured by craniocervical flexion test, and strength of scapular muscles was measured by handheld dynamometer.

Results: The result found that the average craniovertebral angle was 50.76±6.99 degrees. The average length of pectoralis minor muscles were 5.44±1.29 and 5.46±2.14 centimeters, on right and left side, respectively. The average strength of neck flexor muscles was 28.55± 2.29 millimeter of mercury (mmHg). The average strength of scapular muscles which consist of 1) serratus anterior muscles were 7.99±2.08 kilogram (kg) on the right side and 7.77±2.19 kg on the left side 2) rhomboid muscles were 10.03±2.83 kg on the right side and 9.86±2.79 kg on the left side 3) middle trapezius muscles were 12.79±2.57 kg on the right side and 12.66±2.55 kg on the left side 4) lower trapezius muscles were 12.43±2.41 kg on the right side and 12.58±2.39 kg on the left side.

Conclusion: Dental students trend to have tightness of neck extensor and pectoral muscles, whereas strength of neck flexor and scapular muscle are normal.


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Srijessadarak, T., Sae-Lee, D., Paungmali, A., mato, lugkana, wanpen, sawitri, Bumrerraj, S., & Boonprakob, Y. (2017). Investigations of upper crossed syndrome’s characteristics in dental students. Journal of Associated Medical Sciences, 50(3), 404. Retrieved from
Research Articles


1. Rafeemanesh E, Jafari Z, Kashani FO, Rahimpour F. A study on job postures and musculoskeletal illnesses in dentists. Int J Occup Med Environ Health 2013; 26(4): 615-20.

2. Chaiklieng S, Suggaravetsiri P, Boonprakob Y. Work ergonomic hazards for musculoskeletal pain among university office workers. Walailak J Sci & Tech 2010; 7(2): 169-76.

3. Widanarko B, Legg S, Stevenson M, Devereux J, Eng A, Mannetje A, et al. Prevalence of musculoskeletal symptoms in relation to gender, age, and occupational/industrial group. Int J Ind Ergonom 2011; 41: 561-72. doi:10.1016/j.ergon.2011.06.002

4. Chatchawan U, Puntumetakul R, Peungsuwan P, Wanpen S, Boonprakob Y, Phadungkit S, et al. Prevalence of musculoskeletal symptoms in Khon Kaen University students, Thailand. J Med Tech Phys Ther 2012; 25(2): 193-202.

5. Valachi B and Valachi K. Mechanisms leading to musculoskeletal disorders in dentistry. J Am Dent Assoc 2003; 134(10): 1344-50.

6. Nejati P, Lotfian S, Moezy A, Moezy A, Nejati M. The relationship of forward head posture and rounded shoulders with neck pain in Iranian office workers. Med J Islam Repub Iran 2014; 28:26.

7. Ruivo RM, Pezarat-Correia P, Carita AI. Cervical and shoulder postural assessment of adolescents between 15 and 17 years old and association with upper quadrant pain. Braz J Phys Ther 2014; 18(4): 364–71.

8. Page P, Frank CC, Larder R. Assessment and treatment of muscle imbalance: The Janda approach. USA: Human kinetics, 2010.

9. Lynch SS, Thigpen C, Mihalik JP, Prentice WE, Padua D. The effects of an exercise intervention on forward head and rounded shoulder postures in elite swimmers. Br J Sports Med 2010; 44(5): 376-81.

10. Lee KJ, Han HY, Cheon SH, Park SH, Yong MS. The effect of forward head posture on muscle activity during neck protraction and retraction. J Phys Ther Sci 2015; 27(3): 977-9. doi: 10.1589/jpts.27.977.

11. Lewis JS, Valentine RE. The pectoralis minor length test: a study of the intra-rater reliability and diagnostic accuracy in subjects with and without shoulder symptoms. BMC Musculoskelet Disord 2007; 8(64): 1-10.

12. Jull GA, Oleary SP, Falla DL. Clinical assessment of the deep cervical flexor muscles: The craniocervical flexion test. J Manipulative Physiol Ther 2008; 31(7): 525-33. doi: 10.1016/j.jmpt.2008.08.003.

13. Fernández-de-las-Peñas C. Clinical evaluation of cervicogenic headache: A Clinical Perspective. J Man Manip Ther. 2008; 16(2): 81. doi:10.1179/106698108790818440

14. Supasatean W, Boonprakorb Y, Kamolrat T, Mator L, Benjapornlert P, Bumrerraj S, et al. Correlation between abdominal and scapular muscle strength in upper back pain patients with and without scapulocostal syndrome. Bull Chiang Mai Assoc Med Sci 2016; 49(3): 323-37.

15. Michener LA, Boardman ND, Pidcoe PE, Frith AM. Scapular muscle tests in subjects with shoulder pain and functional loss: reliability and construct validity. Phys Ther 2005; 85(11): 1128-38.

16. Cheung Lau HM, Wing Chiu TT, Lam TH. Clinical measurement of craniovertebral angle by electronic head posture instrument: a test of reliability and validity. Man Ther 2009; 14(4): 363-8. doi: 10.1016/j.math.2008.05.004.

17. Lee MY, Lee HY, and Yong MS. Characteristics of cervical position sense in subjects with forward head posture. J Phys Ther Sci 2014; 26(11): 1741-3.

18. Salahzadeh Z, Maroufi N, Ahmadi A, Behtash H, Razmjoo A, Gohari M, et al. Assessment of forward head posture in females: observational and photogrammetry methods. J Back Musculoskelet Rehabil 2013; 2014; 27(2): 131-9. doi: 10.3233/BMR-130426.

19. Silva AG, Punt TD, Sharples P, Vilas-Boas JP, Johnson MI. Head posture and neck pain of chronic nontraumatic origin: a comparison between patients and pain-free persons. Arch Phys Med Rehabil 2009; 90(4): 669-74. doi: 10.1016/j.apmr.2008.10.018.

20. Wong CK, Coleman D, diPersia V, Song J, Wright D. The effects of manual treatment on rounded-shoulder posture,and associated muscle strength. J. Bodyw. Move Ther 2010; 14(4): 326-33. doi: 10.1016/j.jbmt.2009.05.001.

21. Ishida H, Suehiro T, Kurozumi C, Ono K, Ando S, Watanabe S. Correlation between neck slope angle and deep cervical flexor muscle thickness in healthy participants. J Bodyw Mov Ther 2015; 19(4): 717-21. doi: 10.1016/j.jbmt.2015.04.001.

22. Noguchi T, Demura S. Relationship between abdominal strength measured by a newly developed device and abdominal muscle thickness. APE 2014; 4: 70-6. doi: 10.4236/ape.2014.42010.

23. Hassan D, Saman MP, Fatemeh K. Isometric scapulothoracic muscles strength in overhead athletes. Bhu J RNR 2015; 3(1): 332-43.