Objective
To evaluate the clinical usefulness of ultrasonographic measurement of the sternocleidomastoid muscle(SCM) in congenital muscular torticollis.

Method
We studied nine patients(5 males, 4 females) who were diagnosed as a congenital muscular torticollis. We measured the thickness of SCM muscles bilaterally by the ultrasonography and obstetric caliper under sedation, before and after conservative treatment.

Results
Before the treatment, thickness of the SCM muscle was significantly thicker in the lesion side than non-lesion side(p＜0.05). There was significant changes in thickness of the lesion side from the values of the before- to thoses of after-treatment(p＜0.05). Both the difference of thickness and the ratio between lesion and non-lesion side significantly decreased after the treatment(p＜0.05). Obstetric caliper measurement showed no significant changes in the difference of thickness and the ratio between the lesion and non-lesion sides after the treatment.

Conclusion
Ultrasonographic measurement of the thickness of SCM in congenital muscular torticollis was easily applicable, objective, and reliable, thus was an affordable method for both diagnosis and evaluation of the treatment effect.