Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, cervical spondylotic myelopathy (CSM), also called degenerative cervical myelopathy, results from narrowing of the spinal canal (spinal stenosis) ultimately causing compression of the spinal cord. When due to trauma, myelopathy is known as (acute) spinal cord injury. When inflammatory, it is known as myelitis. Disease that is vascular in nature is known as vascular myelopathy. In Asian populations, spinal cord compression often occurs due to a different, inflammatory process affecting the posterior longitudinal ligament. Presentation Clinical signs and symptoms depend on which spinal cord level (cervical, thoracic, or lumbar) is affected and the extent (anterior, posterior, or lateral) of the pathology, and may include: Upper motor neuron signs—weakness, spasticity, clumsiness, altered tonus, hyperreflexia and pathological reflexes, including Hoffmann's sign and inverted plantar reflex (positive Babinski sign) Lower motor neuron signs—weakness, clumsiness in the muscle group innervated at the level of spinal cord compromise, muscle atrophy, hyporeflexia, muscle hypotonicity or flaccidity, fasciculations Sensory deficits Bowel/bladder symptoms and sexual dysfunction Diagnosis Diagnosis of myelopathy Myelopathy is primarily diagnosed by clinical exam findings. Because the term myelopathy describes a clinical syndrome that can be caused by many pathologies the differential diagnosis of myelopathy is extensive. In some cases the onset of myelopathy is rapid, in others, such as CSM, the course may be insidious with symptoms developing slowly over a period of months. As a consequence, the diagnosis of CSM is often delayed. As the disease is thought to be progressive, this may impact negatively on outcome. Diagnosis of etiology Once the clinical diagnosis myelopathy is established, the underlying cause must be investigated. Most commonly this involves medical imaging. The best way to visualize the spinal cord is magnetic resonance imaging (MRI). Apart from T1 and T2 MRI images, which are commonly used for routine diagnosis, more recently researchers are exploring quantitative MRI signals. Further imaging modalities used for evaluating myelopathy include plain X-rays for detecting arthritic changes of the bones, and Computer Tomography, which is often used for pre-operative planning of surgical interventions for cervical spondylotic myelopathy. Angiography is used to examine blood vessels in suspected cases of vascular myelopathy. The presence and severity of myelopathy can also be evaluated by means of transcranial magnetic stimulation (TMS), a neurophysiological method that allows the measurement of the time required for a neural impulse to cross