any structural anomaly of any of the four paired muscles located in the anterior neck below the hyoid bone, within the muscular triangle; these muscles are long and flat in shape, similar to a belt or strap, and are responsible for depressing the hyoid during swallowing; they either originate from or insert on to the hyoid bone and include the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles
abnormal superior pharyngeal constrictor muscle morphology