Oral and maxillofacial surgery/Local anesthesia/Inferior alveolar nerve block

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Oral and maxillofacial surgery
School of Medicine
School of Dentistry

Inferior alveolar nerve block (IANB), also called "inferior dental block" (IDB). Really, it should be called "inferior alveolar and lingual nerve block", but IANB is in most common usage.

This page is a quick guide about how to administer an IANB in the most common fashion. The instructions are for right-handed people. If you are left handed, whenever you read "right", mentally substitute it for "left" and vice versa.

It is advisable to review the main page for this topic:

See also the Wikipedia articles:


  • Deposit local anesthesia (LA) solution into the pterygomandibular space, near to the mandibular formamen on the medial aspect of the mandibular ramus.


  • Before the patient comes in, prepare desired LA solution (see main page) in a gauge 27 long needle. You cannot give reliably successful IANBs with a short needle, and there is also more risk of needle fracture when inserting needles to the hub. Loss of the needle requires a general anesthetic in hospital so the pterygomandibular space can be explored. This surgery carries a risk of nerve damage. Another reason for using this gauge is that the needle is bigger, and therefore less likely to fracture, but also tends to displace, rather than pierce structures like the lingual nerve.
  • Explain procedure (see main page)
  • Sometimes the patient may be lying flat and the clinician may have to stand (e.g. in an operating theater), but most dentists tend to give LA with the patient supine in a dental chair while they sit down, at about in which case stand to their right and
  • Ask the patient to open as wide as possible. This stretches the pterygomandibular raphe and makes it more visible as an anatomic landmark. Mucosa which is under tension also allows the needle to penetrate more easily and with less pain
  • Pick up syringe carefully in left hand and bring it carefully into position in the mouth. It is very common to accidentally stab the patient's chin if you focus only on the injection site.

Lingual nerve lies anteromedial to the inferior alveolar nerve

Why can't I just give infiltrations in the mandible?

  • The cortical plate of bone in the mandible is too thick for the LA to diffuse into the bone and to reach the nerves, as is possible in the maxilla.