#spinal cord

• Amyelia — An extremely rare and severe congenital malformation within the neural tube defects spectrum, characterized by the total absence or complete developmental arrest of the spinal cord. This severe structural anomaly occurs during the first weeks of embryogenesis due to the failure of the posterior neuropore to close, being incompatible with extrauterine life and often associated with other major cranial malformations.
• Arachnoid mater — The middle meningeal membrane, thin, transparent, and completely avascular, situated between the dura mater (externally) and pia mater (internally), surrounding and protecting the brain and spinal cord. It is characterized by a fine reticular structure reminiscent of a spider web and plays a crucial physiological role in defining the subarachnoid space through which cerebrospinal fluid circulates and resorbs.
• Arachnoiditis — A progressive neurological disorder characterized by the chronic inflammation of the arachnoid mater, the middle meningeal membrane surrounding the brain and spinal cord. This pathology leads to the development of scar tissue and fibrous adhesions that can trap and compress spinal nerve roots, causing severe chronic pain, numbness, muscle spasms, and motor impairments, often triggered by infections, spinal surgeries, or irritating chemical substances.
• Ataxoparaplegia — A rare and complex neurological condition characterized by the clinical association of ataxia (lack of movement coordination) with paraplegia (paralysis of the lower limbs). This syndrome is caused by the simultaneous lesion or combined degeneration of the posterior and lateral columns of the spinal cord, encountered in neurosyphilis (tabes dorsalis), subacute combined degeneration, or severe spinal cord trauma.