Medial Branch of Posterior Ramus of Fifth Lumbar Nerve (Right)
Ramus posterior medialis nervi lumbalis quinti
Read moreQuick Facts
Origin: Posterior ramus of the fifth lumbar nerve.
Course: Curves medially across the caudal aspect of lumbosacral zygapophyseal joint and terminates in multifidus.
Branches: Muscular, articular, and interspinous branches.
Supply: Multifidus muscle, zygapophyseal joints, interspinous muscle, and interspinous ligament.
Related parts of the anatomy
Origin
After the posterior ramus of fifth lumbar nerve has traversed through the intertransverse ligament and medial intertransverse muscle, a small medial branch is given off, between fifth lumbar vertebrae and the sacrum.
Course
The fifth lumbar posterior ramus arches over the rostral and dorsal aspect of the ala of the sacrum, lying in the groove formed by the junction of the ala with the root of the superior articular process of the sacrum. Along its course, it divides into intermediate and medial branches. The division occurs opposite the caudal border of the L5-S1 zygapophyseal joint or slightly more proximally. The medial branch curves medially around the caudal aspect of the lumbosacral zygapophyseal joint and terminates in and supplies the multifidus muscle.
Branches
The medial branch gives off three main branches; muscular branches to the multifidus muscle-fascicles; proximal and distal zygapophysial nerves to the rostrally and caudally related zygapophysial joints; an interspinous branch emerges from the medial branch on the vertebral lamina and weaves medially between the fascicles of multifidus to reach the interspinous muscle and ligament.
Supplied Structures
The medial branch supplies the multifidus muscle, zygapophyseal joints (rostral and caudal surfaces), interspinous muscle, and interspinous ligament.
