Ultrasound-guided mental nerve block is useful in the diagnosis and treatment of a variety of painful conditions in areas subserved by the mental nerve, including mental neuralgia, mental nerve entrapment, and pain secondary to herpes zoster (Fig. 13.1). This technique is also useful in providing surgical anesthesia in the distribution of the mental nerve for lesion removal, cosmetic procedures, dental surgery, and laceration repair. The mental nerve can be blocked via either an extraoral or intraoral approach. The intraoral approach to mental nerve block is especially useful in providing surgical anesthesia in the distribution of the mental nerve for lesion removal and laceration repair when a cosmetic result is desired because the intraoral approach avoids distortion of the facial anatomy from local anesthetic infiltration at the surgical site. The intraoral approach is also useful in the pediatric population as the oral mucosa can be anesthetized with topical application of local anesthetic prior to needle placement.

The mental nerve is a pure sensory nerve arising from fibers from the mandibular nerve.

Along with the mental branch of the inferior alveolar artery, the mental nerve exits the mandible via the mental foramen at the level of the second premolar, where it makes a sharp turn superiorly and separates into branches (Fig. 13.2). It is at this point that the nerve is especially vulnerable to trauma and entrapment (Fig. 13.3). The nerve provides cutaneous branches that innervate the lower lip, chin, and corresponding oral mucosa (Fig. 13.4). In rare instances, the mental nerve may exit the mandible via separate mental foramen.