attached to attached to muscle organ hemipenis extrinsic post-anal tail muscle retractor penis magnus muscle UBERON:0035100 M. retractor penis magnus retractor penis magnus A tube-like muscle attaches to the distal tip of the hemipenis and inserts onto the transverse processes of a caudal vertebra. Like that of m. transversus penis, the function of m. retractor penis magnus is difficult to deduce. However, this muscle likely acts to help retract the hemipenis into the cloaca after copulation (Arnold, 1984)[PMID:22753107] transverse process of caudal vertebra