FIG 5. Axial CT scan in a patient with left vocal cord paralysis shows atrophy of the left PCA muscle (arrow indicates normal right PCA muscle; arrowhead, laryngeal pharynx).

FIG 6. T1-weighted axial MR image (800/12) in a patient with a right-sided vagal schwannoma shows atrophy of the right PCA muscle relative to the left (arrowhead indicates normal left PCA muscle).

FIG 7. Axial CT scan through the level of the PCA muscles in a patient with a left-sided vocal cord paralysis. Atrophy of the left PCA muscle is probably present (a rating of 3) although poorly seen, given the lack of fat posterior to it.