Several techniques for infraclavicular nerve blocks have been described. The coracoid approach was first described by Whiffler in the British Journal of Anaesthesia in 1981. This technique was most commonly used with nerve stimulation. The use of ultrasound offers more flexibility in approaches, giving the provider different choices for needle insertion depended on patients’ anatomy and best ultrasound image.
All upper extremity blocks involve the brachial plexus. The brachial plexus arise from the anterior rami of C5-8 and T1 with some contribution from C4 and T2. The rami unite to form superior, middle, and inferior trunks. They occupy the space between the anterior and middle scalene muscles. Each trunk divides into anterior and posterior divisions, which rejoin to form 3 cords: the lateral, posterior, and medial. The medial brachial cutaneous and medial antebrachial cutaneous nerves come off the medial cord. The cords then pass into the axilla and divide into nerve branches: the musculocutaneous, axillary, radial, median, and ulnar (see the image below).
The brachial plexus can be blocked anywhere along its course, from the neck to the axilla.
Formation of brachial plexus rami, trunks, divisions, cords, roots and nerves.