Ultrasound-guided cervical nerve root block is the technique of injecting local anesthetic or steroid into the intertubercular groove outside of the cervical foramen under real-time ultrasound guidance. It has established diagnostic and therapeutic employment for patients suffering symptoms caused by cervical disc disorders and foraminal stenosis. Measures of selective nerve root blockade would have vital clinical utility, especially in multilevel disease or combined with atypical symptoms, where subjective assessment is difficult. This case reported a 47-year-old male patient who suffered from severe radicular pain confined to the index and middle fingers, with weakness of the right upper extremity. He was successfully treated with selective C6, C7 nerve root under ultrasound guidance. For confirmation of the proper analgesia range, laser speckle contrast imaging (LSCI) and infrared thermography (IT) were both constructed over the dorsum of the hands and forearms during the procedure. The results of the off-line analysis suggested LSCI and IT might be considered as alternative measurements for the selective cervical nerve root.