Transverse Cervical Nerve for Landmark-Guided Cervical Cutaneous Analgesia

Neck injections can be painful despite topical anesthesia. Blocking the transverse cervical nerve (TCN) may improve comfort, but clinicians need practical surface landmarks and attention to the external jugular vein (EJV).

In an anatomical mapping series (46 heminecks), the TCN emergence point along the posterior border of the sternocleidomastoid muscle (SCM) was recorded as a percentage of the earlobe-to-lateral clavicular SCM insertion distance (0-100%). In a pilot split-neck study (n=9), the left neck received landmark-guided TCN block with lidocaine at the mapped point (~10 mm depth) before bilateral injections; the right neck received lidocaine 5% cream, applied according to the clinic's routine protocol for 30 minutes prior to injection RESULTS: The TCN emerged at a mean of 53% along the reference line. Complete cutaneous anesthesia occurred in 9/9 participants (95% CI, 66.4-100%). All participants reported lower VAS pain on the blocked side (sign test, p=0.0039). One bruise occurred (1/9; 11.1%; 95% CI, 0.3-48.2%).

A proportional SCM landmark (~53%) provides a simple guide for landmark-based TCN block to reduce discomfort during neck injections. EJV awareness and aspiration are essential for safety.

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