Subdeltoid ultrasound-guided brachial plexus block: A technical description with anatomical correlation and a preliminary case series.

Regional anaesthesia in the emergency department requires reliable techniques with minimal complications. We describe a subdeltoid ultrasound-guided brachial plexus approach targeting a potential "nerve funnel" at the surgical neck of the humerus, bridging infraclavicular and axillary approaches. Cadaveric dissection explored its anatomical basis and correlated it with clinical sonographic findings. This retrospective case series included six adult patients with traumatic upper-limb injuries. Cadaveric observations suggested terminal nerve clustering and proximity of the musculocutaneous and intercostobrachial nerves at the subdeltoid level. All patients achieved adequate anaesthesia with a single 15 mL injection of 0.5% bupivacaine with 4 mg dexamethasone. The mean pain-free duration was 17.3 hours, with consistent tourniquet tolerance and no procedural complications. The subdeltoid approach appears feasible as a single-injection technique for upper-limb procedures. Using a superficial acoustic window and favourable anatomical clustering, it may provide effective coverage with technical simplicity. These preliminary findings require validation in larger prospective studies.