Anterior Middle Superior Alveolar Nerve Block (AMSA)

The nerves anesthetized are the anterior superior nerve and the middle superior nerve when present.  The areas anesthetized are the pulpal tissue from canine to canine or premolar to central if the MSA is present, the buccal attached gingiva and the palatal tissue from the free gingival crest to the midline.  The landmark for insertion for this injection is the area that bisects the premolars and is midway between the free gingival margin and the mid-palatine suture.  The syringe position is a 45 degree angle from the opposite side.  The bevel orientation is towards the bone and there is pressure anesthesia.  The depth of insertion is 2-4 mm with osseous contact.

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