Radiography is not necessary if the patient satisfies ALL of the following low risk criteria:
No midline cervical tenderness
No focal neuro deficits
Normal alertness
No intoxication
No painful distracting injury
C-spine imaging should be considered unless the patient meets all of the above low risk criteria 
Mnemonic - NSAID:
NEXUS cervical spine rule
Canadian cervical spine rule
MR CLEAN
Cervical spine x-ray interpretation
Cervical spine clearance
PALS 
Ultrasound: Pharyngeal
Neck diagnoses