  The 7 standard deviations between the proton rms charge radius from muonic
hydrogen and the CODATA-10 value from hydrogen spectroscopy and
electron-scattering has caused considerable discussions. Here, we review the
theory of the 2S-2P Lamb shift and 2S hyperfine splitting in muonic hydrogen
combining the published contributions and theoretical approaches. The
prediction of these quantities is necessary for the determination of both
proton charge and Zemach radii from the two 2S-2P transition frequencies
measured in muonic hydrogen.
