What areas does an MSA nerve block anesthetize?

What areas does an MSA nerve block anesthetize?

• A. Pulp of maxillary canines and incisors
• B. Pulps of maxillary premolars; MB root of first molar in some patients; buccal periodontal tissues and overlying bone
• C. Pulp of first and second molars
• D. Palatal mucosa over canines and premolars

Answer: (B)

The middle superior alveolar (MSA) nerve block targets the branches of the infraorbital nerve that supply the buccal (cheek-side) aspects of the maxillary premolar region. It anesthetizes the pulps of the maxillary premolars and, in some people, the mesiobuccal root of the first maxillary molar. In addition to the tooth pulps, it blocks the buccal periodontal tissues and the overlying bone in that same area. It does not reliably affect the canines and incisors, which are typically served by the anterior superior alveolar nerve, and it does not numb the palatal mucosa over canines and premolars, which is supplied by the palatal nerves (nasopalatine and greater palatine). The inclusion of the mesiobuccal root of the first molar “in some patients” reflects natural anatomical variation. This combination of targeted pulpal and buccal tissue anesthesia is why the described area is the best fit.

The middle superior alveolar (MSA) nerve block targets the branches of the infraorbital nerve that supply the buccal (cheek-side) aspects of the maxillary premolar region. It anesthetizes the pulps of the maxillary premolars and, in some people, the mesiobuccal root of the first maxillary molar. In addition to the tooth pulps, it blocks the buccal periodontal tissues and the overlying bone in that same area. It does not reliably affect the canines and incisors, which are typically served by the anterior superior alveolar nerve, and it does not numb the palatal mucosa over canines and premolars, which is supplied by the palatal nerves (nasopalatine and greater palatine). The inclusion of the mesiobuccal root of the first molar “in some patients” reflects natural anatomical variation. This combination of targeted pulpal and buccal tissue anesthesia is why the described area is the best fit.