Syringomyelia is a disease caused by the blockage of the<unk> . Blockage of the<unk>  usually occurs at the lower cervical and upper thoracic levels. This typically damages white matter fibers that cross in anterior white commissure, leading to the loss of temperature, pain, and motor function at the affected levels on side opposite to the damage. Other relevant conditions include: * Spina bifida * Arnold-Chiari syndrome * Spinal tumor * Myelomeningocele * Syringomyelia * Hydromyelia. In hydromyelia, a dilation of the<unk>  of the spinal cord is caused by an increase of cerebrospinal fluid. * Syringohydromyelia (i.e., both Syringomyelia and Hydromyelia) * Tethered cord In some cases, the terminal ventricle may cause clinical symptoms due to its expansion.
Central canal
Lacrimal groove
Craniopharyngeal canal
Optic recess
Lacrimal sac
Ateronon
Collateral fissure
Orbital septum