Application-centred Ultrasound Transmission Gel segmentation maps demand to procedural throughput, reimbursement intensity, and infection-risk profile. Radiology/general imaging remains the largest funnel, consuming 52 % of gel volume in 2023, driven by high-frequency superficial exams that require thin, low-impedance layers. Cardiology follows with 21 % of units but 30 % of revenue, because phased-array probes need higher-viscosity, acoustically matched gels sold in 250 ml formats at 1.8× the average price. Obstetrics & gynaecology generates 14 % of demand, where foatal-safety formulations—paraben-free and with neutral pH—are mandatory; volume here is relatively price-inelastic, growing in line with birth rates. Emergency & critical care absorbs 8 % of gel yet posts the fastest volume CAGR (7.2 %) as point-of-care ultrasound adoption accelerates. Musculoskeletal and intraoperative niches together constitute the remaining 5 %, but require sterile, 12 ml foil sachets that carry the highest per-ml margin, illustrating how procedural setting shapes both unit economics and Ultrasound Transmission Gel segmentation strategy.