Conus medullaris
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At the time the article was created Jeremy Jones had no recorded disclosures.
View Jeremy Jones's current disclosuresAt the time the article was last revised Jeremy Jones had no financial relationships to ineligible companies to disclose.
View Jeremy Jones's current disclosuresThe conus medullaris is the terminal end of the spinal cord.
Gross anatomy
After the cord terminates, the nerve roots descend within the spinal canal as individual rootlets, collectively termed the cauda equina. The conus medullaris most commonly terminates at the L1/2 intervertebral disc level in children and adults 1-3.
Extending from the conus is a delicate strand of fibrous tissue called the filum terminale that acts to give longitudinal support to the cord.
Variant anatomy
The termination of the conus medullaris has been reported from mid-T11 to mid-L3 vertebral body levels. The average termination varies from study to study 1-3, but a level at or above the L2/3 intervertebral disc level can be considered normal. A level at L3 vertebral body is equivocal and can be a normal variant or the result of a tethered cord 1.
On fetal MRI, the vertebral bodies can be difficult to count accurately. However, the kidneys may be used as a reference, and a normal conus should not terminate below the lower margin of normally positioned kidneys.
References
- 1. Wilson D & Prince J. John Caffey Award. MR Imaging Determination of the Location of the Normal Conus Medullaris Throughout Childhood. AJR Am J Roentgenol. 1989;152(5):1029-32. doi:10.2214/ajr.152.5.1029 - Pubmed
- 2. Soleiman J, Demaerel P, Rocher S, Maes F, Marchal G. Magnetic Resonance Imaging Study of the Level of Termination of the Conus Medullaris and the Thecal Sac: Influence of Age and Gender. Spine (Phila Pa 1976). 2005;30(16):1875-80. doi:10.1097/01.brs.0000174116.74775.2e - Pubmed
- 3. Kesler H, Dias M, Kalapos P. Termination of the Normal Conus Medullaris in Children: A Whole-Spine Magnetic Resonance Imaging Study. Neurosurg Focus. 2007;23(2):E7. doi:10.3171/FOC-07/08/E7 - Pubmed
Incoming Links
- Spinal pia mater
- Spinal cord
- Holocord presentation
- Thoracolumbar injury classification and severity score (TLICS)
- Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD)
- Filar cyst
- Spinal astrocytoma
- Transpyloric plane
- Artery of Adamkiewicz
- Lumbar enlargement
- Fluoroscopy guided lumbar puncture
- Vertebral artery
- Ventriculus terminalis
- Cyst of the medullary conus
- Coccygeal plexus
- Spinal dural arteriovenous fistula
- Denticulate ligaments
- Syringomyelia
- Myxopapillary ependymoma
- Filum terminale
- Aneurysmal bone cyst
- Spinal cord infarct
- Type II split cord malformation
- Caudal regression syndrome
- Diastematomyelia type I
- Diastematomyelia - type II
- Pseudosinus tract
- Myxopapillary ependymoma
- Diastematomyelia - type II
- Diastematomyelia - type I
- Spinal cord (Gray's illustration)
- Cauda equina (Gray's illustration)
- Zuckerguss of the spine
- Caudal regression syndrome
- Myxopapillary ependymoma
- Subacute combined degeneration of the cord
- Spinal cord astrocytoma
- Guillain-Barré syndrome
- Epidural angiolipoma
- Filar cyst
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