The coccygeal nerves (spinal nerves Co) or tailbone nerves are the last and the smallest pair of spinal nerves. They originate from the conus medullaris (terminal segment of the spinal cord) located in the distal part of the vertebral column. The coccygeal nerves then descend within the cauda equina and exit the vertebral column through the sacral canal. Alternatively, the nerves exit through the sacral hiatus.
The coccygeal nerve contributes to the coccygeal plexus and participates in the sensory innervation of the skin overlying the tailbone (coccyx).
This article will discuss the anatomy and function of the coccygeal nerve.
|Origin||Conus medullaris (terminal segment)|
|Branches||Anterior ramus of coccygeal nerve, posterior ramus of coccygeal nerve|
|Supply||Skin of coccygeal region|
- Origin and course
- Branches and innervation
- Clinical relations
Origin and course
The coccygeal nerves are the 31st pair of spinal nerves. They emerge from the conus medullaris, the termination of the spinal cord. The coccygeal nerve descends within the cauda equina along with the lumbar and sacral spinal nerves.
The coccygeal nerve exits the sacral canal via the sacral hiatus and emerges inferior to the first coccygeal segment. It curves around the lateral margin of the sacrum where its anterior (ventral) ramus then pierces the coccygeus muscle.
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Branches and innervation
The coccygeal nerve terminates in a bifurcation, giving off two terminal branches:
- Anterior (ventral) ramus of coccygeal nerve
- Posterior (dorsal) ramus of coccygeal nerve
The anterior ramus rises after the nerve exits the sacral hiatus. Together with the anterior rami of S4 and S5 spinal nerves, the anterior ramus of the coccygeal nerve participates in the formation of the coccygeal plexus. The coccygeal plexus gives rise to the anococcygeal nerve. This nerve supplies the sacrotuberous ligament as well as the skin over the tailbone.
The posterior ramus of the coccygeal nerve with the communicating branch from the S5 spinal nerve supplies the skin over the back of the tailbone.
Coccydynia or tailbone pain
Tailbone pain or coccydynia is a common clinical condition characterized by pain in the coccygeal region. The patients usually present with sharp or burning pain in the coccygeal region which increases while during physical activity. This condition is usually a consequence of bone injuries that occur in sports activities such as mountain biking, prolonged sitting, or even during the last trimester of pregnancy. The treatment depends on its cause, and it can sometimes include even the coccygeal nerve block to release the pain.
Coccygeal nerve: want to learn more about it?
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