I didn't see the exact answer to your question in the Borisenko paper, since section 2.4 only seems to address immersions of subsets of ℍ<sup>2</sup> into ℝ<sup>3</sup>. However, a perturbation of the pseudosphere, Dini's surface, which is an isometrically embedded one-sided tubular neighborhood of a geodesic in the hyperbolic plane (see https://mathoverflow.net/a/149884/1345), seems to do the trick since it contains arbitrarily large disks in the hyperbolic plane. See [Dini's Surface][1] at the Geometry Center. ![alt text][2] [1]: http://www.geom.uiuc.edu/zoo/diffgeom/surfspace/dini/ [2]: https://i.sstatic.net/VfNkN.gif