Cervical and shoulder postural assessment of adolescents between 15 and 17 years old and association with upper quadrant pain (2024)

Abstract

Background:

There is sparse literature that provides evidence of cervical and shoulderpostural alignment of 15 to 17-year-old adolescents and that analyzes sexdifferences.

Objectives:

To characterize the postural alignment of the head and shoulder in the sagittalplane of 15 to 17-year-old Portuguese adolescents in natural erect standing andexplore the relationships between three postural angles and presence of neck andshoulder pain.

Method:

This cross-sectional study was conducted in two secondary schools in Portugal. 275adolescent students (153 females and 122 males) aged 15 to 17 were evaluated.Sagittal head, cervical, and shoulder angles were measured with photogrammetry andPAS software. The American Shoulder and Elbow Surgeons Shoulder Assessment (ASES)was used to assess shoulder pain, whereas neck pain was self-reported with asingle question.

Results:

Mean values of sagittal head, cervical, and shoulder angles were 17.2±5.7,47.4±5.2, and 51.4±8.5º, respectively. 68% of the participants revealedprotraction of the head, whereas 58% of them had protraction of the shoulder. Theboys showed a significantly higher mean cervical angle, and adolescents with neckpain revealed lower mean cervical angle than adolescents without neck pain. 53% ofthe girls self-reported regular neck pain, contrasting with 19% of the boys.

Conclusions:

This data shows that forward head and protracted shoulder are common posturaldisorders in adolescents, especially in girls. Neck pain is prevalent inadolescents, especially girls, and it is associated with forward head posture.

Keywords: adolescents, cervical, photogrammetry, rehabilitation, posture, shoulder

Introduction

Posture has been defined as the alignment of the body segments at a particular time1 and is an important health indicator2. It must correspond to a specific body position in space which minimizesanti-gravity stresses on body tissues3. Inadequate posture consists of poor interrelations between parts of thebody4. These imperfect interrelations cause muscle tension and shortening, which makesappropriate joint movements more difficult to achieve5 and may cause pain.

Epidemiological studies have shown a high prevalence of spinal postural deviations inchildren and adolescents6^,7, with forward head posture (FHP) and protracted shoulder (PS) posture being twoof the most common postural deviations7. FHP is commonly defined as the protrusion of the head in the sagittal plane sothat the head is placed anterior to the trunk8. It can occur because of anterior translation of the head, lower cervicalflexion or both, and it is claimed to be associated with an increase in upper cervicalextension8. It is associated with shortening of the upper trapezius, the posterior cervicalextensor muscles, the sternocleidomastoid muscle and the levator scapulae muscle9. It is thought that adolescents or patients with neck pain (NP) have a moreforward head posture, thus a smaller craniovertebral (CV) angle in standing, thanage-matched pain-free participants10. PS is a forward displacement of the acromion with reference to the7^th cervical spinous process, frequently associated with a protracted,anterior tilted and internally rotated scapula and with a tightness of the pectoralisminor muscle11.

To study the misalignments outlined above, the photographic measurement of sagittalpostures of cervical spine and shoulder is becoming more widespread, with severalstudies confirming the high reliability of photogrammetry2^,9^,12^-14. To assist with posture assessment from digitized images, specific software hasbeen developed such as PAS/SAPO (Postural Assessment Software)12.

Based on the knowledge that the current literature is still sparse in thecharacterization of the postural alignment of adolescents in a large sample size andthat there is no concrete information on the relationship between neck and shoulder painand sagittal posture of the spine in a standing position, we defined the followingobjectives for this study: 1) to characterize the postural alignment of the head andshoulders in the sagittal plane of 15 to 17-year-old Portuguese adolescents in naturalerect standing; 2) to find the relationship (if any) between the postural angles studiedand neck and shoulder pain; and 3) to analyze sex differences in the postural angles andneck and shoulder pain.

The findings of this study may give researchers further information about cervical andshoulder postural alignment of a specific age group and will help to evaluate therelationship between neck and shoulder pain and posture. Moreover, the results may helpto improve the management of patients with neck pain. This study has the advantage ofhaving evaluated a far larger sample than other studies6^,15 and analyzed sex differences.

Method

Participants

This cross-sectional study was conducted in two public secondary schools, LumiarSecondary School and Padre Antonio Vieira Secondary School, located in the city ofLisbon, Portugal. Male and female adolescent students between the ages of 15 and 17years were eligible to participate. The justification of the ages is to avoid theeffects of the pubertal growth spurt. Participants were excluded if they had visualdeficits, diagnosed balance disorders, musculoskeletal pathologies (e.g. history ofshoulder surgery, cervical or thoracic fracture), were non-ambulatory, displayedfunctional or structural scoliosis, or had excessive thoracic kyphosis. Given thesecriteria, a total of 275 adolescent students (146 females and 129 males) aged 15, 16,or 17 years old [15.76±1.08 y] from 17 different classes (nine from the10^th grade, seven from the 11^th grade, and one from the12^th grade) were evaluated and included in the study.

The participation of all students was voluntary, and written informed consent wasobtained from all participants, and their parents or legal guardians. The study wasapproved by the Research Ethic s Committee of the Faculty of Human Kinetics fromUniversidade de Lisboa, Lisbon, Portugal (approval number: 5/2013).

Procedures

Posture alignment assessment

Standing cervical and shoulder posture was measured with photogrammetry and PASsoftware. When compared to radiographs using the LODOX, the photographs provide validand reliable indicators of the spine6. Also the software PAS has proven to be valid and reliable12. Three angles of measurement were used - sagittal head angle (HT), cervicalangle (CV), and shoulder angle (SH) (Figure 1)- and obtained in the sagittal view as follows:

Figure 1. Adhesive marker placement and postural angles. a sagittal head; bcervical angle; c shoulder angle.

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Sagittal head angle - The angle formed at the intersection of a horizontal linethrough the tragus of the ear and a line joining the tragus of the ear and thelateral canthus of the eye.

Cervical angle - The cervical angle is highly reliable to assess the forward headposition4. It is the angle formed at the intersection of a horizontal line through thespinous process of C7 and a line to the tragus of the ear. In this study, if theangle was less than 50º, the participant was considered to have forward head posture.The selection of 50º as a reference angle was guided by the studies of Diab andMoustafa16 and Yip et al.17, with the latter reporting 55.02±2.86 as a normal range. As is well known,subjects with FHP have a significantly smaller cervical angle when compared withnormal subjects18.

Shoulder angle - The angle formed at the intersection of the line between themidpoint of the humerus and spinous process of C7 and the horizontal line through themidpoint of the humerus. In the present study, we considered 52º as the referenceangle based on Thigpen et al.19 who evaluated 310 participants in a standing position and reported 2.6º±15.3as a normal range, and Brink et al.20, who evaluated 15 to 17 year-olds and reported a mean shoulder angle value of51.35º±17.2º, and based on the premise that subjects with protracted shoulder have asignificantly smaller shoulder angle when compared with normal subjects15. We considered an individual to have PS if the angle was less than 52º.

All measurements were taken by the same researcher who was experienced in theassessment of postural alignment. The photographing took place in the gymnasium ofthe 2 secondary schools with the areas arranged identically. Landmarks were placed onthe floor to ensure the same positioning of all subjects in front of the camera andto ensure that the subject was aligned perpendicular to the camera. A landmark wasplaced in front of a white wall to ensure a contrast of the subjects against thebackground. One Canon Power Shot A4000 IS was supported on a Manfrotto tripod, model055 CLB, three meters away from the line marking the position of the subject. Theheight of the tripod was adjusted so the middle of the objective lens was 130 cmabove the ground. A calibration board was placed in the field of view and alignedwith the subject to allow referencing of horizontal and vertical axes from thephotographs. The calibration board also displayed each subject's identificationnumber. For positioning, the adolescent was instructed to stand comfortably in anormal standing position and to look straight ahead. Marks on the floor ensured thatall subjects were in the same place.

Before photographing, the researcher put reflective markers (styrofoam balls with 20mm diameter) on the following anatomical points on the right side of the subject´sbody: tragus of the ear, lateral canthus of the eye, spinous process of C7, andmidpoint of the humerus. With these markers we were able to calculate the sagittalhead angle, cervical angle, and shoulder angle.

Self-assessment of shoulder pain and function and neck pain

The American Shoulder and Elbow Surgeons Shoulder Assessment (ASES) form wastranslated and cross-culturally adapted to the Portuguese language. This Portugueseversion was then used to record the presence of shoulder pain and function in thesubjects. The questionnaire addressed self-evaluation of pain using a visual analogscale and activities of daily living questionnaire. A high total score indicates lowperceived pain and low dysfunction in activities of daily living. After the posturalassessment and administration of the ASES questionnaire, the students were asked toanswer yes or no to the following question: do you feel neck pain regularly? Withthis question we also wanted to address neck pain as an outcome measure.

Reliability study

A separate preparatory study to confirm the inter- and intra-rater reliability ofcomputerized photogrammetry using the PAS was performed. The study sample consistedof 17 subjects from the 10^th grade. Three physical therapists (all menfrom 26 to 32 years old), who had used the PAS/SAPO before but were not regularusers, were invited to participate as raters. Each student was photographed in thesame conditions as detailed before in the main study, and pictures were taken of theparticipants in random order. Using the PAS, the three raters took the measurements,which were then used to calculate the inter-rater reliability. These procedures wererepeated one week later by therapist A, and the results were compared to assess theintra-rater reliability.

Statistical analysis

All statistical analyses were performed using specific software (SPSS version 20),and the α value was defined in 0.05. Intra-rater reliability was assessed using type2.1 intraclass correlation coefficient (ICC), whereas the inter-rater reliability wasassessed using ICC(3.1).

The Shapiro-Wilk test was used to assess normality. To analyze differences betweensexes and between patients with and without neck pain (NP) in the three posturalangles and ASES scores, the independent-samples t-test was applied. A chi-square testwas used to assess the relationship between the forward head and cervical pain.Relationships between the three postural angles and ASES were examined by calculatingSpearman's rho correlation coefficient (r_s).

Results

Reliability study

The reliability of the photographic measurement is shown in Table 1. A total of 17 subjects (14 females and 3 males) aged 15to 17 years were recruited for the reliability study. The ICC (2.1) values for theshoulder angle and for the cervical angle reported good reliability, with 0.78 and0.66 respectively, whereas the values for the HT angle (0.83) revealed very goodintra-rater reliability. All the ICC (3.1) values for the three angles, in theinter-rater reliability, reported a very good reliability, with the SEMs of thephotographic measurement ranging between 1.64 and 2.35.

Table 1. Intra-rater and inter-rater reliability findings: ICC and SEM values forall angles.

Measurement	Intra-rater reliability			Inter-rater reliability
	ICC (95% CI)	SEM	MDC	ICC (95% CI)	SEM	MDC
Sagitall Head Angle Cervical Angle Shoulder Angle	0.83 (0.60-0.94) 0.66(0.26-0.87) 0.78 (0.49-0.92)	2.72 3.54 4.03	7.54 9.81 11.18	0.88 (0.75-0.95) 0.87(0.74-0.95) 0.96 (0.92-0.99)	2.35 1.85 1.64	6.51 5.13 4.55

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^ICC

- Intraclass correlation coefficient

^SEM

- standard error of measurement

Experimental study

Sample

A total of 275 adolescents, 153 girls and 122 boys (age 15±1 year), participated inthe study. Sex and descriptive values for the three postural angles and ASES scoresare described in Table 2.

Table 2. Descriptive values for the postural angles and ASES scores (n=275) andeffect of gender and neck pain in postural angles and ASES scores.

	Overall					Females	Males
	All (n=275)	No NP (n=170)	NP (n=105)	t	p	All (n=153)	All (n=122)	t	p
Sagittal head tilt angle	17.2±5.7	17.6±5.7	16.4±5.7	1.76	0.008	16.15±5.3	18.4±6.03	–3.3	0.001
Cervical angle	47.4±5.174	47.96±4.79	46.46 ±5.6	2.358	0.019 *	46.55±5.2	48.43±4.91	–3.05	0.002*
Shoulder angle	51.4±8.548	50.95 ±8.18	52.24±9.13	–1.219	0.224	51.09±8.27	51.88±8.92	–0.765	0.445
ASES Scores (right)	93.3±9.53	95.06±6.68	90.46±12.40	3.99	0.000*	92.31±10.7	94.55±7.59	3.136	0.053
ASES Scores (left)	91.6± 9.38	93.13±7.75	89.10±11.14	3.52	0.000*	90.46±9.99	93.01±8.37	1.252	0.025*
	Females				Males
	No NP (n=72)	NP (n=81)	t	p	No NP (n=98)	NP (n=24)	t	p
Sagittal head tilt angle	16.5±5.1	15.8±5.5	0.67	0.5	18.5±6.0	18.1±6.3	0.3	0.76
Cervical angle	47.38±4.76	45.8±5.6	1.86	0.0048*	48.38±4.79	48.63±5.5	–0.221	0.825
Shoulder angle	50.72±7.72	51.4±8.78	–0.52	0.603	51.12±8.4	55.02±9.89	–1.944	0.054
ASES Scores (right)	94.92±5.85	89.98±13.33	2.91	0.004*	95.16±7.25	92.07±8.57	1.800	0.074*
ASES Scores (left)	92.53±6.96	88.62±11.8	2.45	0.015*	93.56±8.29	90.76±8.51	1.479	0.142

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^ASES

- American shoulder and elbow surgeons shoulder assessment

^NP

- neck pain

Statistically significant difference (p<0.05).

Bearing in mind the reference values outlined before, of the 275 adolescents studied,188 (68%) had forward head (FH) with a cervical angle less than 50º, while 131 (58%)had a shoulder angle less than 52º, revealing a PS. These values are shown in Figure 2.

Figure 2. Percentage of students experiencing forward head and/ or protractedshoulder (PS).

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Sex, neck pain, postural angles and ASES

The examination of the head and shoulder posture measurements to identify the effectof sex and NP on postural angles and ASES scores using the t-test is reported inTable 2. Significant differences wereobserved between boys and girls with respect to the HT angle and the CV angle, withthe boys reporting a higher mean value (18.4±6.03 vs 16.15±5.31, and 48.43±4.91 vs46.55±5.24, respectively).

105 adolescents (38.2%) of the 275 reported having NP regularly. The overall NP groupshowed a significantly lower mean CV angle (46.5±5.6 vs 47.9±4.79), whereas nostatistically significant difference was found between patients and pain-freeparticipants for the HT angle (t=1.76, P>.05) and SH angle(t=-1.2, P>.05). When trying to associate CV and neck pain usingchi squared test for forward head and cervical pain, it was clear that neck pain wasmore prevalent in adolescents with FH than adolescents without FH (29.8% vs8.4%).

When introducing the sex item, 53% of the girls (n=81) reported NP regularly,contrasting with 19.7% of the boys (n=24). Girls with NP also reported asignificantly lower cervical angle than the girls without NP (45.81±5.6 Vs47.38±4.76º).

Spearman's rho correlation coefficients among the ASES and CV and SH angle arepresented in Table 3. None of variablespresented a high (r>0.8) and statistically significant correlation other than theexpected ASES (right) and ASES (left) (r=0.853).

Table 3. Spearman's rho correlations between ASES and the cervical and shoulderangle.

n=275	ASES right	ASES left	Sagittal Head Angle	Cervical Angle	Shoulder Angle
ASES right		0.853* p=0.00	0.031 p=0.592	0.141* p=0.02	-0.001 p=0.0981
ASES left	0.85* p=0.00		0.050 p=0.410	0.141* p=0.004	0.02 p=0.698
Sagittal Head Angle	0.031 p=0.592	0.050 p=0.410		0.07 p=0.245	-0.156 *p=0.010
Cervical Angle	0.141*p=0.02	0.141* p=0.004	0.07 p=0.245		0.057 p=0.293
Shoulder Angle	0.001*p=0.0981	0.02 p=0.698	-0.156 *p=0.010	0.057 p=0.293

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Correlation is significant at the 0.05 level (2-tailed).

Discussion

Reliability study

The present study demonstrated very good reliability for the intra-rater measurementsfor the HT angle and good reliability for the cervical and shoulder angle in thenormal standing posture. With this data, we can suggest that the participants' upperquadrant standing posture did not change significantly over repeated testing.Regarding the inter-rater measurements in the same image for all the variablesstudied, the very good reliability values are in accordance with the values found byFalla et al.18.

Experimental study

Descriptive statistics

A large percentage of the subjects revealed some degree of postural abnormality inthe cervical and/or shoulder region, with 68% and 58% of the students showing FH andPS, respectively, and 48% of the total sample showing both misalignments.

The incorrect use of heavy backpacks22, psychosocial factors such as depression or stress23, the lack of ergonomic school furniture24, and the extended hours in incorrect postures in school and in front ofcomputers and television20 may be responsible for this finding.

Specifying the angles studied, we chose HT, CV, and SH angles because they are themost commonly cited in the literature, enabling the comparison of results. Theseanalyses are reliable and help us to characterize a patient's posture in terms ofhead and shoulder position8.

The HT angle measures the alignment of the upper cervical spine25. The overall mean HT angle registered (17.2º) is similar to a study byChansirinukor et al.15 with adolescents (13-16 years old) in standing position, which reported amean HT angle of 16.3º. De Wall et al.26 recommended that a suitable HT angle would be 15º above horizontal.

For the CV angle, a smaller angle indicates a more forward head posture16. The mean CV angle obtained (47.4º) was similar to the mean reported by vanNiekerk et al.6 who evaluated 40 adolescents aged 16 to 17 years. In another study with 94students aged 15 to17 years, Brink et al.20 found a smaller CV angle of 39.27º (7.9), which was considered the cause ofupper quadrant pain.

The SH angle is an angle that provides a measurement of the shoulder position. Themean SH angle obtained (51º) is the same as the one found by Brink et al.20 and very similar to the one found by van Niekerk et al.6 (50º). Both studies evaluated adolescents. A smaller angle indicates aPS.

Effect of postural angles in pain

In an overall view, 105 (38%) participants reported feeling NP regularly. Thisfinding is concurrent with other studies that found a high prevalence ofself-reported upper quadrant pain among adolescents27, with the shoulder and neck regions becoming more and more cited as the areasof greatest discomfort28. Hakala et al.29 in a study with adolescents reports NP is common in adolescents, with aroundone in four reporting NP at least weekly.

This NP can be associated with musculoskeletal disorders, with several studiesassociating an excessive FH position with NP8^,10^,17^,30. For example, Chiu et al.30 found that approximately 60% of individuals with NP had FHP. The assumptionthat greater neck flexion is worse is based on the biomechanical principle relatingan increased lever arm (from head center of mass to head/neck and neck/thorax axes ofrotation) with increased gross moment. Johnson31 suggested that prolonged FHP might increase loading to the non-contractilestructures and abnormal stress on the posterior cervical structures and causemyofascial pain.

In this study, 68% of the students showed FH, which could predispose then to regularneck pain. Our results confirmed that the adolescents with NP showed a significantlylower CV angle than those without NP (46.5º vs 48.0º). The interdependence betweenthe NP and the CV angles was confirmed with the NP being more prevalent inadolescents with FH than adolescents without FH (29.8% vs 8.4%).

This high prevalence of adolescents with FH and NP can be a reflection of modernPortuguese society, with information technology having a tremendous impact on thelife of adolescents through daily use of internet, computers, and console games andwith obesity on the rise.

Effect of sex on the postural angles and pain

Girls showed a lower resting CV angle than boys (46.5º vs 48.4º), which is inaccordance with Hakala et al.29, who found females had 2-3º more neck flexion than males in a study ofstanding cervical habitual posture in adolescents. Also in adults, significant sexdifferences in CV angle have been observed previously, with women having a moreforward head position than men29. This posture of greater flexion in females can be attributable topsychosocial issues, such as stress, or partly associated with the development ofsecondary sex characteristics in females.

Contrary to the current study, two studies with small samples reported no sexdifferences for cervical habitual posture in adolescents and pre-adolescents2^,6. More research is required to clarify the role of sex in cervicalposture.

Regarding shoulder posture, we found similar mean values in boys and girls. This isin accordance with Raine and Twomey.33, who also reported this similarity in all age groups studied, including the17-29 age group.

Regarding NP, 52.9% of the girls reported regular NP, contrasting with 19% of theboys. This result is in accordance with previous cross-sectional studies that showeda greater female predisposition to musculoskeletal pain34. The reasons for this remain speculative, but we can hypothesize that thisresult may have been influenced by differences in musculoskeletal systems, such asthe fact that girls revealed a significantly lower mean CV angle. Other explanationsmay be related to differences in behavioral factors, with boys having the tendency todeny pain and girls to overestimate their symptoms at puberty and to have morestudy-related stress.

Limitations

The study aimed to minimize errors and bias by recruiting a large sample, settingcareful positioning and testing procedures, and blinding the digitization procedure.However it still has some limitations such as the fact that it describes only thealignment of the spine and the shoulder girdle at rest. Therefore the findings cannot begeneralized to alignment during functional tasks, especially when the upper limb ismoving or loaded.

Another limitation refers to the fact that we have only evaluated the dominant-side. Tobe more complete, postural alterations could be observed in a non-dominant side aswell.

It should also be highlighted that future studies need to characterize the entire spinegiven the potential influence postures at the lumbar spine have on head position. Alsosome other variables such as anthropometric variables (e.g. height), degree of thoracickyphosis or physical activity level must be taken into account.

Conclusion

The results of the present study showed that the photographic measurement is a reliabletool to assess the standing sagittal posture of the cervical spine and shoulder. It alsoshowed that forward head and protracted shoulder are common postural disorders inadolescents. 68% and 58% of the adolescents revealed anteriorization of the head andprotraction of the shoulder, respectively. The subjects with neck pain had a moreforward head posture. Sex was also found to have an important effect on posture and neckpain, with girls revealing a lower cervical angle and more neck pain.

Acknowledgements

To the Foundation for Science and Technology Portugal (grant no. SFRH/BD/77633/2011) fortheir support.

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