Background and purpose: One of the most common postural disorders in today’s societies is the forward head posture (FHP) that is associated with numerous musculoskeletal complications. Considering sternocleidomastoid attachments to the neck, it seems that it would be negatively influenced by such postural deviations. The aim of this study was to compare the sternocleidomastoid muscle thickness in women with normal head posture (NHP) and FHP.

Materials and methods: A case-control study was done in which 18 female students (mean age 24.5±3.3) with FHP and 18 female controls (mean age 23.4±2.5) with NHP were participated. Bilateral sternocleidomastoid muscle thickness were measured in supine position in both groups using ultrasonography. Data analysis was carried out in SPSS V.16.

Results: There was no significant difference in thickness of sternocleidomastoid between individuals with FHP and NHP (P>0.05). Also, no significant difference was seen between the two groups in muscle thicknesses on either side of the neck (P> 0.05). In other words, thickness was found to be symmetric on both sides of the neck in both groups.

Conclusion: According to the results, FHP did not impose any morphological changes on sternocleidomastoid muscle at the fifth cervical vertebral level. Although measurement of the thickness of this muscle in other vertebral levels is recommended for future studies.