The loss of a lower limb severely affects mobility and quality of life, with the fit of the prosthesis being essential for user comfort and functionality. Techniques for manufacturing prosthetic sockets, such as plaster casting, are time-consuming and dependent on the prosthetist’s expertise, while advanced imaging modalities like computed tomography (CT) and magnetic resonance imaging (MRI) are costly and introduce positioning-related inaccuracies. Ultrasound (US) presents a promising alternative for capturing both external and internal limb structures in a non-invasive manner, though mostly limited to 2D. This study investigates a novel approach for 3D reconstruction of US scans using a N-shaped fiducial pattern integrated into a liner applied to the limb. The fiducials facilitate registration of US images to reconstruct a 3D model. Validation on a limb phantom yielded an average reconstruction accuracy of 1.5 mm for bone and 1.7 mm for skin on a partial volume. While our findings demonstrate feasibility of the method, future work aims to enhance reconstruction accuracy by refining image alignment techniques and expanding the scanning approach to the whole limb.