Pseudodysphagia due to omohyoid muscle syndrome.

Omohyoid muscle syndrome (OMS) is a rare clinical condition that has the pathognomonic feature of the appearance of a lateral neck mass when swallowing due to dysfunction of the omohyoid muscle (OH). We present two cases of typical OMS with electrophysiologic and dynamic imaging studies. The study results indicate that OMS is caused mainly by the loosening of the fascial attachment to the intermediate tendon of the OH. The characteristic clinical features and pathomechanism underlying OMS are also discussed.