Nerve Block: Mental

Background

• Mental nerve innervates the skin of the chin and mucous membranes of the lower lip (from lip anteriorly to alveolar process and to the mid body of the mandible) - by blocking this nerve you can have adequate anesthesia for complicated laceration closures
• NOTE: this block does NOT anesthetize the teeth or mandibular soft tissue (see Nerve Block: Inferior Alveolar)

Indications

• Trauma or need to perform painful procedure on area innervated by mental nerve

Contraindications

• Infection overlying injection site
• Previous allergic reaction to local anesthesic used
• Distortion of anatomic landmarks

Equipment Needed

• Local anesthesic
• Chloraprep
• Syringe with blunt fill needle and 27ga (or 25ga) needle

Procedure

• Obtain informed consent
• Place patient in semi-recumbent position
• Draw up 2-5cc of anesthetic into syringe
• Locate the mental foramen by retracting the cheek laterally and palpating between the 2 lower premolar teeth
• Insert the needle along the lower gum into the buccal fold between the premolar teeth without placing the needle directly into the foramen
• Aspirate; if no blood, inject a few cc's of anesthetic slowly (avoid injecting directly into the foramen as to prevent damage to the neurovascular bundle)
• For lacerations over the midline, block the mental nerve on each side of the face to anesthetize crossover fibers
• Block may also be performed extraorally by palpating and approaching the mandible slightly laterally to make contact just outside the mental foramen

Complications

• Bleeding
• Infection
• Pain
• Needle fracture
• Neuropraxia

See Also

• Nerve blocks (main)
• Local anesthetic systemic toxicity

References

• Amsterdam J and Kilgore K. Regional Anesthesia of the Head and Neck. In: Roberts and Hedges' Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia, PA: Elsevier; 2014