What is the typical injection depth for the PSA nerve block?

The typical injection depth for the PSA (Posterior Superior Alveolar) nerve block is generally around 16 mm. This specific depth is chosen to effectively anesthetize the PSA nerve, which innervates the maxillary molars except for the mesiobuccal root of the first molar.

When administering the PSA block, it's important to insert the needle at the correct angle and depth to ensure that the anesthetic solution is delivered in proximity to the nerve. At approximately 16 mm, the needle typically reaches the area where the maxillary nerve branches, allowing optimal distribution of the anesthetic to achieve the desired pain control for dental procedures involving the maxillary molars.

In contrast, the other injection depths listed do not align with the clinical guidelines for this procedure. Shallower depths like 5 mm and 8 mm are unlikely to provide adequate access to the PSA nerve, running the risk of insufficient anesthesia. Similarly, a depth of 30 mm is excessive and potentially poses a risk of complications, such as needle placement in an unintended location or injury to surrounding structures. Therefore, 16 mm is the most appropriate and commonly taught depth for achieving successful anesthesia with the PSA nerve block.