Sacrum The number of sacral vertebrae varies slightly. For instance, the S1S5 vertebrae of a horse will fuse, the S1S3 of a dog will fuse, and four pelvic vertebrae of a rat will fuse between the lumbar and the caudal vertebrae of its tail. The "Stegosaurus" dinosaur had a greatly enlarged neural canal in the sacrum, characterized as a "posterior brain case”. The sacrum is a complex structure providing support for the spine and accommodation for the spinal nerves. It also articulates with the hip bones. The sacrum has a base, an apex, and three surfaces – a pelvic, dorsal and
Ver sacrum of Indo-Iranian human and warrior gods with animal forms: among the Iranian god of victory "V(e)r(e)thragna" 's incarnations, seven are of animal form, including the bull, horse, boar and hawk, each of which is associated at one time or another with a "ver sacrum" and Roman army insignia. On the "recto" of coins from Campania appears a human character bearing over his head that of a boar, and on the "verso" the word "ROMA". German scholar C. Koch interprets this character as god Quirinus, since he identifies the boar, "aper", as the animal symbol of the god. Dumézil remarks that