Accessory process
Processus accessorius
Definition
The accessory process of a vertebra is a small bony projection found on the posterior aspect of the transverse processes of the lumbar vertebrae. It serves as an attachment point for muscles and ligaments, specifically the longissimus muscle, which is part of the erector spinae muscle group.
Note: in the Gray's, the accessory process is described as an inferior tubercle of the lower thoracic vertebrae situated at the back part of the base of the costal process, rudiment of the original transverse process.
References
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
