A Low-Cost Serratus Anterior Plane Block Phantom With a Thoracodorsal Artery Analogue and Pleural-Breach Feedback

Ultrasound-guided serratus anterior plane block (SAPB) is an evidence-supported component of multimodal analgesia for rib fractures, but training requires learners to integrate chest-wall sonoanatomy with safe needle control near vascular and pleural structures.We describe a low-cost part-task trainer, meaning a simulator designed to rehearse selected components of a procedure rather than the entire clinical encounter, and propose a staged pathway from simulation to supervised patient practice.Four wooden stacking blocks support a tongue-depressor scaffold.Transverse tongue depressors represent ribs, and a water-filled examination glove sits immediately beneath them as a simulated pleural safety boundary.Two chicken fillets represent serratus anterior and latissimus dorsi, with a single layer of cling film creating the superficial fascial plane.A fluid-filled thermometer probe cover placed in this plane represents the thoracodorsal artery.The primary task is superficial SAPB, with in-plane needle visualisation, vessel avoidance and hydrodissection.An optional deep-plane station is designed to provide immediate visible feedback if an unsafe trajectory breaches the water-filled glove; it does not simulate pneumothorax physiology.One final prototype was evaluated in a proof-of-concept bench session.Post hoc estimates from archived ultrasound images placed the superficial target plane at approximately 8-10 mm, and the rib surrogates at approximately 18-22 mm depth.No validity, reliability, durability or learner-outcome testing was performed.The model and proposed seven-step pathway are therefore offered as a starting point for structured preclinical preparation, not as a stand-alone competency or entrustment tool.