There are multiple definitions:

1. internal rotation lag sign(English)

   • see m. subscapularis
   • Shoulder and other joints

2. iterative reweighted least squares(English)

   • ICP, IMCP, SVD
   • Statistics

3. International Restless Legs Syndrome(English)

   • a scoring system
   • CGI-S, LIPC, MHD, RLS
   • Musculoskeletal system, Pathology, Scoring systems/scales
   • https://doi.org…2X.2023.2283589