Does ESPB performed at the level of T4 cover axillary area? A cadaveric study

Erector spinae plane block (ESPB) has rapidly become popular following its first description by Forero et al. in 2016 [1,2]. Previous randomized controlled trials demonstrated the efficacy of ESPB for breast cancer surgery [3,4], however, still some issues such as the exact mechanism of action and spread of local anesthetic (LA) remain unclear [2]. In addition, none of the previous cadaveric studies have evaluated the axillary spread following.