episkeletal,a.Anat.|ɛpɪˈskɛlɪtəl| [f. epi- + skelet-on + -al1.] Of muscles: Situated upon the skeleton, i.e. lying above the horizontal plane of the vertebral axis. 1871Huxley Anat. Vert. ii. 45 The episkeletal muscles are developed out of the protovertebræ.