Which landmarks help identify the PSA nerve block site?

Which landmarks help identify the PSA nerve block site?

• A. Mucobuccal fold, maxillary tuberosity, zygomatic process of maxilla
• B. Infraorbital rim, nasal spine
• C. The palatal raphe
• D. The mandible ramus

Answer: (A)

When locating a PSA nerve block, the landmarks that guide you are the mucobuccal fold over the second molar, the maxillary tuberosity, and the zygomatic process of the maxilla. The posterior superior alveolar nerves travel in the posterior maxilla near the tuberosity as they enter bone, so you place the needle in the soft tissue just above the second molar (the mucobuccal fold) and direct it toward the area of the maxillary tuberosity. The tuberosity serves as a stable bony reference point for how far back and inward to aim, while the palpable border formed by the zygomatic process helps you orient the needle medially without over-insertion. Together, these landmarks position you to deposit anesthetic near where the PSA nerves enter the maxilla, maximizing success. Other options point to different blocks: the infraorbital rim and nasal spine would guide an infraorbital block, the palatal raphe is relevant to palatal injections such as the nasopalatine or greater palatine nerves, and the mandible ramus relates to the inferior alveolar block.

When locating a PSA nerve block, the landmarks that guide you are the mucobuccal fold over the second molar, the maxillary tuberosity, and the zygomatic process of the maxilla. The posterior superior alveolar nerves travel in the posterior maxilla near the tuberosity as they enter bone, so you place the needle in the soft tissue just above the second molar (the mucobuccal fold) and direct it toward the area of the maxillary tuberosity. The tuberosity serves as a stable bony reference point for how far back and inward to aim, while the palpable border formed by the zygomatic process helps you orient the needle medially without over-insertion. Together, these landmarks position you to deposit anesthetic near where the PSA nerves enter the maxilla, maximizing success.

Other options point to different blocks: the infraorbital rim and nasal spine would guide an infraorbital block, the palatal raphe is relevant to palatal injections such as the nasopalatine or greater palatine nerves, and the mandible ramus relates to the inferior alveolar block.