Medial Brachial Cutaneous Nerve Block

Indications and Clinical Considerations

Medial brachial cutaneous nerve block is used primarily as an adjunct to brachial plexus block rather than as a stand-alone regional anesthesia and pain management procedure. The medial brachial cutaneous nerve is the smallest branch of the brachial plexus and is often not adequately blocked when performing standard brachial plexus block techniques. This means that the medial and posterior aspect of the arm just below the axilla remains unanesthetized, making prolonged use of a pneumatic tourniquet or the performance of surgical procedures in this region problematic ( Fig. 53.1 ).

FIG. 53.1, Intercostobrachial nerve block is not commonly used as a stand-alone pain management technique; rather, it is used to augment brachial plexus block and to provide anesthesia of the medial cutaneous surface of the arm and axilla to decrease tourniquet pain during intravenous regional anesthesia.

Clinically Relevant Anatomy

The medial brachial cutaneous nerve is formed from fibers originating from the C8 and T1 roots ( Fig. 53.2 ). These roots can be difficult to block adequately when performing brachial plexus block. The fibers of the medial brachial cutaneous nerve communicate with the fibers of the intercostobrachial nerve, which has its origin in the second intercostal nerve. These nerves exit the axilla outside the brachial plexus sheath and travel superficially parallel to the triceps muscle. The superficial location of both of these nerves makes them easily accessible for neural blockade ( Fig. 53.3 ). The sensory distribution of these nerves lies directly beneath the area compressed by a pneumatic tourniquet ( Fig. 53.4 ).