The functional and biomechanical modifications of the spine of Scutisorex somereni, the hero shrew: spinal musculature

Abstract

The spine of Scutisorex somereni, the hero shrew, is probably the most highly modified among the vertebrates (Kingdon, 1974), yet no description of the accompanying spinal musculature has been published. This paper describes the anatomy and proposed functions of the major epaxial and hypaxial muscle groups of Scutisorex. The unusual vertebral morphology of this species is accompanied by major modifications in some of the spinal muscle groups. The transverse spinalis muscles are the most modified, and this is probably related to the presence of bony interdigitating tubercles on the vertebrae. The longissimus muscles possess long tendons that share attachment with the iliocostalis muscles. The iliopsoas muscles and their sites of attachment are greatly enlarged in comparison to those of Blarina and Rattus. Much of the spinal musculature reflects the highly modified state of the Scutisorex vertebrae. The unique behavioural function of the Scutisorex spinal modification, if any exists, is not known