Peripheral oxygen saturation (SpO₂) is a key non-invasive parameter for assessing systemic oxygenation, widely used in emergency, critical care, and outpatient settings. While fingertip pulse oximetry remains the clinical standard, its reliability is often compromised by motion artifacts, poor peripheral perfusion, skin pigmentation, hypothermia, and anatomical or environmental factors. These limitations are especially critical in patients with low SpO₂ levels, where conventional sensors may fail to detect rapid desaturation events. To address these challenges, this work explores alternative anatomical sites for SpO₂ measurement using a custom-designed probe. The device enables data acquisition from arterial territories such as the neck, earlobe, and wrist, offering a robust alternative when fingertip readings are unreliable. Preliminary findings demonstrate the feasibility of obtaining consistent SpO₂ signals from these locations under varied physiological and environmental conditions. This approach may improve monitoring accuracy in non-stationary scenarios and enhance the applicability of pulse oximetry in high-demand clinical environments.