Míguez-Fernández M, et al. - Researchers here investigated the accuracy of ultrasound for recognizing the fascial planes and the paraneural space of the nerves in the knee, infiltrating them, and achieving a correct anatomical diffusion, as well as for establishing access routes to avoid intraneural infiltration. In 16 cryopreserved lower extremities of the dissection room of the Faculty of Medicine and Health Sciences, University of Barcelona, colorant was injected in nerves of the knee in the guidance of ultrasound after they were visualized. They attained the exact location of the nerves by ultrasound in 98.75% of the cases, accurate visualization of the needle by ultrasound in 82.5%, the hypoechogenic image around the nerve after infiltration in 82.5%, and a correct paraneural infiltration in 76.25% of cases. These outcomes suggest that high-definition ultrasound allows location of the peripheral nerves and adjacent structures as well as the fasciae that surround them, and hence enables performance of infiltrations in the paraneural spaces.