The anaesthetic implications of an aberrant artery in the supraclavicular fossa

An aberrant artery was noted in the supraclavicular fossa on attempting to provide a supraclavicular brachial plexus block under ultrasound guidance for a distal forearm procedure in a 27‐year‐old man. The probe (6–12 MHz linear array, LOGIQ P7, GE Healthcare, Chicago, USA) was aligned in the transverse axis. We believe that the aberrant artery is likely to be the transverse cervical artery (TCA) because of its location, lying superiorly to the brachial plexus (Fig. 1a–c). The TCA can arise either directly from the subclavian artery or as a branch of the thyrocervical trunk. It is usually seen in the interscalene groove, crossing medially to laterally, anterior to the scalene muscles, and either anteriorly to or between the divisions of the brachial plexus [1]. However, it was absent in the interscalene groove in this case (Fig. 1d). This unusual location of the TCA is reported in only 2% of the population [2].

Figure 1.

(a) Presence of transverse cervical artery anterior to brachial plexus at the supraclavicular fossa; (b) colour Doppler showing the transverse cervical artery lying superiorly to brachial plexus; the brachial plexus is located superolaterally to the subclavian artery; (c) Doppler imaging confirming the aberrant vessel is arterial; (d) absence of transverse cervical artery at the interscalene groove as ultrasound probe is moved cranially. The only vascular structure visualised is the subclavian artery. TCA = transverse cervical artery, SCA = subclavian artery, BP = brachial plexus, ASM = anterior scalene muscle, MSM = middle scalene muscle.

An aberrant dorsal scapular artery identified during a supraclavicular brachial plexus block was recently reported by Hong et al [3]. In that case, the artery lay in the trajectory of the needle for the ‘corner pocket’ approach, but the block could still be performed via an intertruncal approach in the supraclavicular fossa. In our case, the insertion of the needle along the ultrasound beam was not possible because of the potential risk of injury to the aberrant TCA. We therefore chose to perform an alternative brachial plexus block via the axillary approach.

The presence of aberrant vessels may require an alternative approach when performing a block to reduce the risk of vascular injury. They may also interfere with the spread of local anaesthetic, resulting in inadequate block [4].