Middle Superior Alveolar Nerve Block Technique
What it numbs:
The (MSA) Middle superior alveolar nerve block provides pulpal anesthesia to the maxillary premolars and mesial buccal root of the maxillary first molar and the supporting buccal soft tissue and bone. Lingual tissue is not anesthetized. It is located between the ASA and the PSA and is not present on all patients.
A 27-gauge short needle is most commonly used. A 25-guage short or long needle is recommended.
Patient position is supine or semi-supine with mouth partially open.
For the right MSA nerve block and right handed operator, sit at an 10 o'clock position directly facing the patient.
For the left MSA nerve block and right handed operator, sit at an 8 or 9 o'clock position directly facing the patient.
The landmarks are the apex of the second premolar and the mucobuccal fold.
The target area and injection site is located at the height of the buccal fold above the apex to the maxillary second premolar.
The bevel of the needle should be toward the bone and inserted until the tip is well above the apex of the second premolar.
Aspirate, if after two negative aspirations slowly inject 1/2 of the cartridge over 30 seconds.
Document in patient record, what injection you gave, who gave it, what kind of anesthetic, how much anesthetic, negative aspiration, no complications, ect.
For more information and references:
Handbook of Local Anesthesia by Malamed