sentences:  The proatlas is an inverted V-shaped piece of bone with a dorsal keel and is quite large relative to the atlas, which is made up of two separate neural arches.The axis has a low, subrectangular neural spine; neural spines grow taller along the cervical vertebrae, with that of the third cervical vertebra being twice as tall as long and that of the seventh being almost five times as tall as long.The dorsal vertebrae are relatively long compared to their width, with length always more than half the width across the transverse processes.