Figure 2. For low-volume blocks (less than 10 cc), we recommend a single-operator technique. A two-operator technique (see Figure 3) can be used if the operator is a novice and would benefit from normal saline (NS) hydrodissection to ensure proper needle visualization. The operator is using an in-plane technique to perform an interscalene brachial plexus block. SCM: sternocleidomastoid muscle; AS: anterior scalene muscle; MS: middle scalene muscle; yellow dashed line: brachial plexus at the level of the interscalene muscles.