Which of the following is not true about acute retropharyngeal abscess

CLINICAL FEATURES 1. Dysphagia and difficulty in breathing are prominent symptoms as the abscess obstructs the air and food passages. 2. Stridor and croupy cough may be present. 3. Toicollis. The neck becomes stiff and the head is kept extended. 4. The bulge in the posterior pharyngeal wall. Usually seen on one side of the midline. Radiograph of soft tissue, lateral view of the neck shows widening of preveebral shadow and possibly even the presence of gas (Ref: Diseases of ear, nose and throat, P.L Dhingra, 7th edition, page 300)