Figure 1.

Ultrasound image of the three muscle layers.

Notes: TM, RMM, and ESM overlying the T2 TP. LA spread is seen in between the ESM and T2 TP.

Abbreviations: ESM, erector spinae muscle; LA, local anesthetic; RMM, rhomboid major muscle; TM, trapezius muscle; TP, transverse process.