What condition causes pressure on the spinal cord or nerve roots?

A herniated disk occurs when the soft material inside a spinal disk protrudes through a tear in the tougher exterior, potentially pressing on the spinal cord or adjacent nerve roots. This condition can lead to various symptoms, including pain, tingling, or weakness in the limbs, depending on the location and severity of the herniation. It is a mechanical issue that directly impacts the structures of the spine, causing significant discomfort and neurological symptoms due to the pressure exerted on the nerve tissues.

In contrast, the other conditions listed do not primarily involve direct mechanical pressure on the spinal cord or nerve roots in the same manner. Parkinson's disease is a degenerative neurological condition that affects movement and doesn’t directly cause pressure on spinal anatomy. Sciatica refers to pain along the sciatic nerve pathway, generally resulting from compression or irritation of the nerve itself, often due to a herniated disk, but it is not the primary cause of pressure. Meningitis is an inflammation of the protective membranes surrounding the brain and spinal cord, typically due to infection, which can lead to other neurological complications but does not directly involve physical pressure from a herniated structure.