<P> Three portions or tubercles can be noticed in a transverse process of a lower lumbar vertebrae : the lateral or costiform process , the mammillary process , and the accessory process . The costiform is lateral , the mammillary is superior ( cranial ) , and the accessory is inferior ( caudal ) . The mammillary is connected in the lumbar region with the back part of the superior articular process . The accessory process is situated at the back part of the base of the transverse process . The tallest and thickest costiform process is usually that of L5 . </P>
where are the mammillary processes located on a typical lumbar vertebra
connected in the lumbar region with the back part of the superior articular process