This is the most
popular and widely accepted theory which could account for the varying
positions assumed by a paralysed vocal cord. This theory was first
proposed by Wagner and Grossman (1897). This theory states that in
complete paralysis of recurrent laryngeal nerve the cord lies in the paramedian
position because the intact cricothyroid muscle adducts the cord.
(Because the superior laryngeal nerve is intact). If the superior
laryngeal nerve is also paralysed the cord will assume an intermediate position
because of the loss of adductive force. This theory has been confirmed by
electro myological studies.