Ultrasound transducer placement on the neck with ultrasound image

Image A: For an ultrasound-guided interscalene block, the ultrasound transducer is placed in a horizontal (axial) position on the neck superior to the clavicle. Image B: Corresponding ultrasound image obtained for performing an interscalene block. The white line is around the brachial plexus in the interscalene groove.