Which section of the brachial plexus is blocked with a supraclavicular block?

Which section of the brachial plexus is blocked with a supraclavicular block?

• A. Roots
• B. Trunks
• C. Divisions
• D. Cords

Answer: (B)

The main idea is that where you inject determines which part of the brachial plexus is anesthetized. A supraclavicular block places local anesthetic where the plexus is most compact as it passes over the first rib, just above the clavicle, near the subclavian artery. In this region the fibers are organized into trunks (upper, middle, lower) before they split into divisions. Blocking at the trunk level affects all the nerve fibers destined for the entire upper limb, providing a dense, rapid block for many shoulder through hand procedures. If you were aiming for roots, you’d be near the scalene muscles, affecting the individual nerve roots as they emerge. Blocking divisions would affect fibers after they’ve split from the trunks, and blocking cords would occur more distally, in the infraclavicular area, after the plexus has reorganized into cords.

The main idea is that where you inject determines which part of the brachial plexus is anesthetized. A supraclavicular block places local anesthetic where the plexus is most compact as it passes over the first rib, just above the clavicle, near the subclavian artery. In this region the fibers are organized into trunks (upper, middle, lower) before they split into divisions. Blocking at the trunk level affects all the nerve fibers destined for the entire upper limb, providing a dense, rapid block for many shoulder through hand procedures.

If you were aiming for roots, you’d be near the scalene muscles, affecting the individual nerve roots as they emerge. Blocking divisions would affect fibers after they’ve split from the trunks, and blocking cords would occur more distally, in the infraclavicular area, after the plexus has reorganized into cords.