Editing Syringomyelia (section)

== Pathogenesis ==
The pathogenesis of syringomyelia is debated. The cerebrospinal fluid also serves to cushion the [[Human brain|brain]]. Excess cerebrospinal fluid in the [[central canal]] of the [[spinal cord]] is called hydromyelia. This term refers to increased cerebrospinal fluid that is contained within the [[ependyma]] of the central canal.  When fluid dissects into the surrounding [[white matter]] forming a cystic cavity or [[Syrinx (medicine)|syrinx]], the term syringomyelia is applied.  As these conditions coexist in the majority of cases, the term syringohydromyelia is applied. The terms are used interchangeably.<ref>{{Cite journal |last1=Koyanagi |first1=Izumi |last2=Houkin |first2=Kiyohiro |date=2010 |title=Pathogenesis of syringomyelia associated with Chiari type 1 malformation: review of evidences and proposal of a new hypothesis |journal=Neurosurgical Review |volume=33 |issue=3 |pages=271–284; discussion 284–285 |doi=10.1007/s10143-010-0266-5 |pmid=20532585 }}</ref>

It has been observed that obstruction of the cerebrospinal fluid spaces in the subarachnoid space can result in syrinx formation, and alleviation of the obstruction may improve symptoms.  A number of pathological conditions can cause an obstruction of the normal cerebrospinal fluid spaces. These include [[Chiari malformation]], spinal [[arachnoiditis]], [[scoliosis]], spinal [[vertebrae]] misalignment, spinal [[tumors]], [[spina bifida]], and others.  The reasons that blockage of the cerebrospinal fluid space within the subarachnoid space can result in syrinx formation are not fully understood although a small posterior fossa is one known cause.  It is unclear if syrinx fluid originates from bulk movement of cerebrospinal fluid into the spinal cord, from bulk transmural movement of blood fluids through the spinal [[vasculature]] into the syrinx, or from a combination of both. Recent work suggests that central nervous system compliance is the underlying problem for the central nervous system, and also that hydrocephalus and syringomyelia have related causes.<ref>{{Cite journal |last1=Heiss |first1=John D |last2=Jarvis |first2=Katie |last3=Smith |first3=René K |last4=Eskioglu |first4=Eric |last5=Gierthmuehlen |first5=Mortimer |last6=Patronas |first6=Nicholas J |last7=Butman |first7=John A |last8=Argersinger |first8=Davis P |last9=Lonser |first9=Russell R |last10=Oldfield |first10=Edward H |date=2019 |title=Origin of Syrinx Fluid in Syringomyelia: A Physiological Study |journal=Neurosurgery |volume=84 |issue=2 |pages=457–468 |doi=10.1093/neuros/nyy072 |pmc=6500882 |pmid=29618081 }}</ref>