Fig. 1.

A photograph of the needle placement in the mental foramen under ultrasound guidance (10-12 MHz linear transducer). (A) In the actual patient. (B) Anterior view in a human skull model, which is empirically depicted. The transducer (white box) was moved like ① for identifying the mental foramen and mental foramen was positioned at the end of transducer ②. (C) An ultrasound image of the radiofrequency needle in the mental foramen (10-12 MHz linear transducer, long-axis in-plane technique). The cleft within the hyperechoic line indicates the mental foramen. The radiofrequency needle has passed through the mental foramen and is indicated with arrow heads.