Fig. 9
From: Fascial plane blocks for cardiothoracic surgery: a narrative review
A ESPB performed with the patient in sitting position before general anesthesia induction. B Sono-anatomy of the ESPB block: trapezius (uppermost), rhomboid (middle), and erector spinae (lowermost) are identified. The hyperechoic T4 transverse process is individuated inferior to the erector spinae muscle. TR, trapezius muscle; RH, rhomboid muscle; ESM, erector spinae muscle; T4, transverse process