has muscle origin has muscle origin has muscle insertion has muscle insertion iliac crest extensor caudae muscle extensor caudae lateralis muscle UBERON:0035095 extensor caudae lateralis A muscle that originates via a robust tendon from a tuberosity on the cranial aspect of the iliac crest and via fleshy fibers from the caudoventral aspect of the pelvis, the lateral aspects of the transverse processes of Ca2-8 or 9, and the horizontal intramuscular septum. M. externsor caudae lateralis fascia of tail