**2.6 Pelvic autonomic nerve system**

In terms of quality of life, the importance of not only oncological outcomes but also functional outcomes such as urinary function, sexual function, and defecatory function after rectal cancer surgery have been emphasized. Urinary dysfunction after rectal surgery occurs in approximately 27%, and it includes difficulty emptying the bladder and incontinence [30, 31]. Sexual dysfunction for males consists of erectile dysfunction, absence of ejaculation, or retrograde ejaculation. For females, it causes sexual dysfunction such as impaired ability to achieve orgasm, decreased vaginal secretion, or dyspareunia [15]. The major cause of postoperative urogenital dysfunction is autonomic nerve damage that occurs during surgery. As minimally invasive surgery such as laparoscopy and robotic approach develops, meticulous nerve preserving surgery became possible with good visualization of the pelvic autonomic nerves [32–34]. To preserve the postoperative urogenital function, a thorough understanding of the anatomy of the pelvic autonomic nerve is crucial.
