Intercostal Nerve Block-Area of Anesthesia-Indications-Procedure

Intercostal Nerve Block

Area of Anesthesia

The skin and the parietal pleura cover the outer and inner surfaces of each intercostal space, respectively; the 7th to 11th intercostal nerves supply the skin and the parietal peritoneum covering the outer and inner surfaces of the abdominal wall, respectively. Therefore, an intercostal nerve block will also anesthetize these areas. In addition, the periosteum of the adjacent ribs is anesthetized

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Indications

Intercostal nerve block is indicated for repair of lacerations of the thoracic and abdominal walls, for relief of pain in rib fractures, and to allow pain-free respiratory movements.

Procedure

To produce analgesia of the anterior and lateral thoracic and abdominal walls, the intercostal nerve should be blocked before the lateral cutaneous branch arises at the midaxillary line. The ribs may be identified by counting down from the 2nd (opposite sternal angle) or up from the 12th. The needle is directed toward the rib near the lower border and the tip comes to rest near the subcostal groove, where the local anesthetic is infiltrated around the nerve. Remember that the order of structures lying in the neurovascular bundle from above downward is intercostal vein, artery, and nerve and that these structures are situated between the posterior intercostal membrane of the internal intercostal muscle and the parietal pleura. Furthermore, laterally, the nerve lies between the internal intercostal muscle and the innermost intercostal muscle.