Posterior Ramus of Fifth Sacral Nerve (Right)
Ramus posterior nervi sacralis quinti
Read moreQuick Facts
Origin: Fifth sacral nerve (S5).
Course: The posterior ramus emerges from the sacral hiatus, caudal to the multifidus muscle.
Branches: Forms neuronal loops on dorsum of the sacrum with the posterior rami of S4 and Co.
Supply: Sensory innervation to the skin over the coccyx.
Origin
The posterior (dorsal) ramus of fifth sacral nerve originates as one of two terminal branches of the fifth sacral nerve, the other being the anterior ramus.
Course
The posterior ramus of fifth sacral nerve is smaller compared to the preceding upper sacral rami. It emerges from the sacral hiatus (along with the Co nerve) just medial to the sacral cornu of the same side. It proceeds inferiorly and laterally, wrapping around the inferior tip of the sacral cornu. The posterior ramus then passes posteriorly and inferiorly, while being caudal to the multifidus muscle.
Branches
The posterior ramus of fifth sacral nerve unites with the posterior rami of the fourth sacral and coccygeal nerves to form neuronal loops posterior to the sacrum.
Supplied Structures & Function
Filaments from the loops provide sensory innervation to the skin over the coccyx.
