Relationship of Cervicothoracic Curvature with Muscle Strength and Endurance in Subjects with Neck Pain

Purpose: The purpose of the study is to determine the changes seen in cervicothoracic curvature with increasing age in normal and neck pain subjects and also to study, relationship of cervicothoracic curvature with deep neck flexor muscle function and pain level. Material & Method: A group of 10 normal subjects were recruited for reliability study of photographic method. Age and sex matched 30 normal and 30 neck pain subjects were also recruited. Both the groups were divided into three age groups i.e.31-40, 41-50 and 51-60 years with 10 subjects in each. To determine cervicothoracic curvature, lateral profile photographs were taken for both the groups and using AutoCAD software cervicothoracic kyphosis angles were measured at C6 (C4 - C6- T4), C7 (C4 - C7- T4) and T1 (C4 - C6- T4) levels. For neck pain subjects, the angle average (of all the 3 levels) was compared with deep flexor muscle strength, endurance and pain level. Results : The intraclass correlation coefficients for Interrater reliability indicated high reliability with ICC at C6=0.86, at C7=0.80 and at T1=0.88. Statistical analysis was done using one-way ANOVA & Tukey's HSD at all three levels for both the groups. Cervicothoracic kyphosis was increased with age and the increase was more prominent in subjects with neck pain. At C7, angle showed early changes i.e. in forth decade in neck pain subjects compared to normal. The pain intensity and muscle functions were correlated with average cervicothoracic angle using Pearson's co-relation in neck pain subjects. There was statistically significant positive correlation between cervicothoracic angle average and deep flexor muscle strength (r=.598, p=.000). However, no statistically significant relationship was established for muscle endurance and pain intensity. Conclusion: It was concluded that degenerative changes at C7 vertebra were progressed early in neck pain subjects and their deep flexors strength reduces as the cervicothoracic kyphosis increases.