Chapter 31C. Ultrasound-Guided Supraclavicular Brachial Plexus Block
Regarding anatomy, which of the following statements is correct?
A. The block is performed where divisions are formed from the trunks.
B. The dorsal scapular artery crosses posterior to the middle scalene muscle.
C. The subclavian artery passes anterior to the anterior scalene muscle.
D. The superficial and lateral branches come from C8 and T1.
A is correct. Because the trunks and divisions of the brachial plexus are relatively close as they pass over the first rib, the extension and quality of anesthesia are favorable.
B is incorrect. The dorsal scapular artery is often seen within the plexus
C is incorrect. The subclavian artery passes between anterior and middle scalene muscle.
D is incorrect. The superficial and lateral branches come from C5 to C7.
Regarding ultrasound appearance, which of the following statements is correct?
A. The brachial plexus is seen as a hypoechoic structure deep to the artery.
B. The brachial plexus is typically visualized at a 1–3 cm depth.
C. The first rib is seen as a hyperechoic line with acoustic enhancement.
D. The pleura is seen as a hyperechoic static line.
B is correct. See Figure 31C–1.
Supraclavicular brachial plexus block: transducer position just proximal the clavicle and needle insertion. The brachial plexus is very shallow at this location, typically 1–3 cm; therefore, inclination of the needle should be equally shallow. The image also shows the caudal tilt that is useful in obtaining best image of the plexus.
(Images from NYSORA Continuing Medical Education.)
A is incorrect. The brachial plexus is seen as a hypoechoic structure posterior and superficial to the artery.
C is incorrect. The rib casts an acoustic shadow. Acoustic enhancement can be seen deep to the vascular structures.
D is incorrect. Typical for the pleura is the dynamic sliding motion of the visceral pleura in synchrony with the patient’s respiration.
Regarding distribution, which part of the arm is never anesthetised by a supraclavicular block?
C. Skin of the proximal part of the medial side of the arm