[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › Inferior alveolar nerve [Nervous system](https://durgical.com/en/anatomy/system/nervous-system/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # Inferior alveolar nerve The inferior alveolar nerve runs inside the lower jaw and gives feeling to the lower teeth, lip and chin; dentists numb it for lower dental work. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=inferior_alveolar_nerve&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A V3 branch running through the jawbone, coming out at the chin as the mental nerve. ## What it does Feeling of the lower teeth, lip and chin; numbed for dental work. ## Key points - Nerve block landmarks: the coronoid notch on the front of the ramus and the pterygomandibular raphe; the nerve lies in the pterygomandibular space just above the lingula and the mandibular foramen - Numbness of the lower lip and chin on one side after lower third molar surgery, implants or a mandibular fracture points to injury of this nerve or its mental branch - The lingual nerve lies just in front of it in the pterygomandibular space, so the block usually numbs the side of the [tongue](https://durgical.com/en/anatomy/tongue/) as well ## Key facts **Roots** V3; enters the mandibular foramen, exits the mental foramen as the mental nerve **Moves** Nerve to [mylohyoid](https://durgical.com/en/anatomy/mylohyoid-muscle/) (leaves before the mandibular foramen): mylohyoid and anterior belly of the [digastric](https://durgical.com/en/anatomy/anterior-belly-of-digastric-muscle/) **Feeling from** Lower teeth; lower lip and chin (mental nerve) ## Relations **Course** Branch of the posterior trunk of the [V3 mandibular](https://durgical.com/en/anatomy/anterior-division-of-mandibular-nerve/) nerve; descends deep to the [lateral pterygoid](https://durgical.com/en/anatomy/superior-head-of-lateral-pterygoid-muscle/), between the [sphenomandibular ligament](https://durgical.com/en/anatomy/sphenomandibular-ligament/) and the ramus, enters the mandibular foramen, runs forward in the mandibular canal below the molar and premolar roots and leaves through the [mental foramen](https://durgical.com/en/anatomy/mental-foramen/) as the mental nerve, while an incisive branch continues to the canine and incisors **Medial** The sphenomandibular ligament and the [medial pterygoid](https://durgical.com/en/anatomy/medial-pterygoid-muscle/), with the [lingual nerve](https://durgical.com/en/anatomy/lingual-nerve/) in front **Lateral** The ramus of the [mandible](https://durgical.com/en/anatomy/mandible/) **Above** In the mandibular canal, the roots of the lower molars, especially the third molar, whose roots can touch or groove the canal ## How to find it The mental foramen, where the mental nerve emerges, usually lies below the second premolar (some texts: between the two premolars), about halfway between the gum line and the lower border of the mandible. ## Examination - Light touch and two-point discrimination on the lower lip and chin, compared with the other side, map the numb area after dental surgery or a fracture ## On imaging A panoramic radiograph or cone-beam CT shows the mandibular canal as a dark band with white borders; darkening of a third molar root or a break in the canal's white line suggests the root lies close to the nerve. ## Clinical notes - Fractures of the angle and body of the mandible can stretch or tear it in the canal, leaving the lip and chin numb - In jaws without teeth, bone loss brings the mental foramen close to the top of the ridge, where a denture can press on the mental nerve - Incomplete anaesthesia after a block can come from extra supply, such as the nerve to mylohyoid or fibres crossing the midline from the other side ## Anatomical variants - A bifid (double) mandibular canal is seen on some radiographs and can explain a block that does not fully work ## Related conditions - [Dental caries](https://durgical.com/en/conditions/dental-caries/) - [Mandible fracture](https://durgical.com/en/conditions/mandible-fracture/) ## Test yourself Think of the answer, then tap the question to see it. ## What are the landmarks for an inferior alveolar nerve block? The coronoid notch and the pterygomandibular raphe; the nerve lies in the pterygomandibular space just above the lingula and mandibular foramen. ## Why does an inferior alveolar nerve block usually numb the side of the tongue too? The lingual nerve lies just in front of it in the pterygomandibular space. ## Where does the inferior alveolar nerve end, and what does injury after third molar surgery cause? It leaves the mental foramen as the mental nerve; injury numbs the lower lip and chin on that side. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/inferior-alveolar-nerve/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** nervus alveolaris inferior TA2 6274 **Official Spanish (DeCS)** Nervios alveolar inferior y mentoniano **English (TA2)** Inferior alveolar nerve **Also called** nervus alveolaris mandibularis Sources: Terminologia Anatomica (TA2); [Anatomy, Head and Neck: Alveolar Nerve](https://www.ncbi.nlm.nih.gov/books/NBK546712/); [Inferior Alveolar Nerve Block](https://www.ncbi.nlm.nih.gov/books/NBK564368/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/inferior-alveolar-nerve/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/inferior-alveolar-nerve/