Lingual nerve and related nerves
This section summarises the anatomy, common mechanisms, clinical features, emergency assessment and initial management of lingual‑nerve injuries, with practical points for the ED clinician on localisation, referral and governance. It highlights distinctions from neighbouring trigeminal branches important in examination and exam questions, and references relevant UK interventional procedure and governance guidance where useful (NICE IPG218, IPG149, IPG285; NICE IPG715; RCEM NAP8).
Anatomy and clinical relevance
- The lingual nerve is a sensory branch of the mandibular division (V3) of the trigeminal nerve (CN V).
- It supplies general sensation (touch, pain, temperature) to the anterior two‑thirds of the tongue and the floor of mouth.
- It carries taste fibres (special visceral afferents) from the anterior two‑thirds of the tongue via the chorda tympani (branch of the facial nerve, CN VII).
- It conveys parasympathetic preganglionic fibres to the submandibular and sublingual glands.
- Iatrogenic injury is most commonly associated with lower third‑molar (wisdom tooth) extraction; reported temporary paraesthesia after extraction is approximately 2% and permanent deficit approximately 0.2% in procedure series.
- Lingual‑nerve paraesthesia is also a recognised complication of other intra‑oral procedures (for example sialendoscopy, frenotomy) and may occur after local anaesthetic injections (see NICE IPG218; IPG149).
Mechanisms of injury
- Direct trauma during oral surgery, especially lower third‑molar removal.
- Stretch, compression or devascularisation during surgical manipulation.
- Needle injury from intra‑oral...