Superficial cervical plexus block

For the superficial cervical plexus block using anatomic landmarks, a line is drawn from the mastoid process to the C6 transverse process (ie, Chassaignac tubercle) along the posterior border of the sternocleidomastoid muscle (line shown in blue). The midpoint of this line is marked (red dot) as the injection site. After negative aspiration, 10 to 15 mL of local anesthetic is injected in 5-mL increments along the posterior border of the sternocleidomastoid muscle, fanning the injection 2 to 3 cm above and below the needle insertion site, with gentle aspiration between injections. Injection deeper than 2 cm should be avoided. Refer to UpToDate content on nerve blocks of the neck for more details.