- Indications: elbow, forearm, hand surgery
- Landmarks: medial clavicular head, coracoid process
- Nerve stimulation: hand twitch at 0.2–0.5 mA
- Local anesthetic: 25–35 mL
Patient position and needle insertion for infraclavicular brachial plexus block.
The infraclavicular block is a method of accomplishing brachial plexus anesthesia below the level of the clavicle. Experience with basic brachial plexus techniques and understanding of the anatomy of the infraclavicular fossa and axilla is necessary for its safe and efficient implementation. This block is well suited for hand, wrist, elbow, and distal arm surgery. It also provides excellent analgesia for an arm tourniquet. Infraclavicular block is functionally similar to supraclavicular block, therefore the two techniques are often used interchangeably, depending on whether the patient's anatomy is more conducive to one or the other.
The infraclavicular block is performed below the clavicle, where the axillary vessels and the cords of the brachial plexus lie deep to the pectoralis muscles, just inferior and slightly medial to the coracoid process. The boundaries of the space are the pectoralis minor and major muscles anteriorly, ribs medially, clavicle and the coracoid process superiorly, and humerus laterally. The connective tissue sheath surrounding the plexus also contains the axillary artery and vein. Axillary and musculocutaneous nerves may leave the common tissue sheath at or before the coracoid process in 50% of patients (Table 14-1 and Figure 14-2). Consequently, deltoid and biceps twitches should not be accepted as reliable signs of infraclavicular brachial plexus identification.
Table 14-1 Distribution of the Branches of the Brachial Plexus |Favorite Table|Download (.pdf)
Table 14-1 Distribution of the Branches of the Brachial Plexus
- Medial and lateral pectoral nerves (motor to pectoralis muscles)
- Subscapular nerves (motor to subscapularis and teres major)
|Arm, forearm, shoulder, hand|
- Medial cutaneous nerve of the arm
- Medial cutaneous nerve of the forearm
Functional organization of the brachial plexus into trunks, divisions, and cords.
The important anatomic structures are exposed in Figure 14-3.
Anatomy of the infraclavicular fossa. Shown are retracted pectoralis muscles (1), clavicle (2), chest wall (3), axillary (subclavian) artery and vein (4) and brachial plexus "wrapped" around the artery (5).
Distribution of Anesthesia/Analgesia
The typical distribution of anesthesia following an infraclavicular brachial plexus block includes the hand, wrist, forearm, elbow, and distal arm (Figure 14-4). The skin of the axilla and proximal medial arm (unshaded areas) are not anesthetized (intercostobrachial nerve).