PECS I&II blocks

A 12-15 MHz linear ultrasound probe is placed at a midclavicular line below the clavicle. The probe is moved inferolaterally to the level of the 3rd rib. With a slight medial tilt, the three layers of muscles are identified: pectoralis major, pectoralis minor and serratus anterior. When performing both blocks simultaneously, single puncture site can be used to preserve near-field imaging with deposition of the LA between the layers of the serratus anterior and pectoralis minor (PECS II), followed by needle withdrawal and injection between the pectoralis minor and pectoralis major (PECS I)