This prospective observational study aims to evaluate the relationship between ultrasound-derived rectus abdominis muscle thickness and thickening fraction and postoperative opioid consumption in geriatric patients undergoing abdominal surgery. Preoperative ultrasonographic measurements will be performed during routine clinical care, and postoperative pain scores and analgesic requirements will be recorded within the first 24 hours. The findings may help improve individualized analgesic strategies by identifying patient-specific predictors of postoperative opioid needs.