Posterior Ramus of Fifth Lumbar Nerve (Left)
Ramus posterior nervi lumbalis quinti
Read moreQuick Facts
Origin: Fifth lumbar nerve.
Course: Arches over the ala of the sacrum.
Branches: Medial and intermediate branches.
Supply: The intermediate branch supplies motor innervation to the lumbar part of longissimus thoracis. The medial branch supplies motor innervation to the multifidus and sensory articular branches to the facets for superior and inferior articular processes.
Related parts of the anatomy
Origin
The posterior ramus of fifth lumbar nerve (L5) emerges as one of two branches of the L5. The other is the anterior ramus of the same fifth lumbar nerve.
Course
After branching out from the fifth lumbar nerve, the posterior ramus passes posteriorly, arching over the ala of the sacrum. This posterior ramus is much longer than the other lumbar dorsal rami (Bogduk, Wilson and Tynan, 1982).
Branches
The posterior ramus of the fifth lumbar nerve divides into intermediate and medial branches.
Supplied Structures & Function
The intermediate branch supplies motor innervation to the lumbar fibers of the longissimus thoracis muscle. The medial branch supplies motor innervation to the multifidus muscle and sensory articular branches to the facets for superior and inferior articular processes.
References
Bogduk, N., Wilson, A. S. and Tynan, W. (1982) 'The human lumbar dorsal rami', J Anat, 134(Pt 2), pp. 383-97.
