On plain radiography, prevertebral space should be less than 6 mm at C3 vertebral level in children; while in adults, the space should be less than 6 mm at C2 level and less than 22 mm at C6 level. Causes of enlarged prevertebral space could be edema, hematoma, abscess, tumors, and post surgical changes. File:CT of prevertebral space.jpg|
CT scan with upper limits of the thickness of the prevertebral space at different levels. ==References==