Posterior Root of Fifth Sacral Nerve (Left)
Radix posterior nervi sacralis quinti
Read moreQuick Facts
Origin: In or just ventral to the sacral hiatus.
Course: Ventrally from the sacral hiatus and superiorly, within the vertebral canal, towards the posterior surface of the appropriate spinal cord level.
Branches: Unnamed rootlets just prior to entering the spinal cord.
Supply: Sensory innervation from the perianal region.
Origin
The posterior root of the fifth sacral nerve originates in, or just anterior, to the opening of the sacral hiatus. It is at this point that the fourth sacral nerve splits into anterior and posterior roots.
Course
The posterior root of the fifth sacral nerve runs ventrally from the sacral hiatus into the vertebral canal. Here, it runs superiorly towards its corresponding spinal cord level in a large bundle of nerve roots called the cauda equina. The posterior root splits into smaller rootlets before entering the dorsal aspect of the spinal cord.
Branches
The posterior root of the fifth sacral nerve branches into a number of smaller rootlets, shortly before entering the dorsal aspect of the spinal cord.
Supplied Structures
The posterior root of the fifth sacral nerve carries sensory innervation from the perianal region surrounding the anus.
