Neck semispinalis capitis muscle size in sitting and prone positions measured by real-time ultrasonography

Abstract

Objective: To examine the reliability of measurements of semispinalis capitis muscle (SECM) cross-sectional area (CSA) in prone and sitting positions, and to compare the muscle size in these two positions. Design: Semispinalis capitis CSA was measured twice a day on two successive days with a real-time ultrasound apparatus. Subjects: Eighteen males (aged 19–34 years) and 28 females (aged 19–34 years) were studied for the reliability test. Seven males and 12 females were randomly selected to compare SECM size in sitting and prone positions. Results: The intraclass correlation coefficient (ICC) for repeatability measurements was r = 0.98 for the two positions. The correlation of the CSA in sitting and in prone positions was r = 0.93 ( p <0.01). There were no significant differences between CSA, linear dimensions and shape ratio of SECM in the two positions. Conclusions: In this study SECM ultrasonography appeared to be an accurate method in both positions, and position as such had no significant effects on the SECM cross-sectional size. Such accuracy allows neck muscle evaluation in clinical diagnosis and in follow-up studies during neck rehabilitation programmes.