"Tension headaches occur when neck and scalp muscles become tense, or contract. The muscle contractions can be a response to stress, depression, a head injury, or anxiety."
"The exact cause or causes of tension headache are unknown. Experts used to think that the pain of tension headache stemmed from muscle contraction in the face, neck and scalp, perhaps as a result of heightened emotions, tension or stress. But research suggests that there doesn't appear to be a significant increase in muscle tension in people diagnosed with tension headache."
"Because the meninges are the only intracranial sites from which pain can be evoked, headaches that accompany intracranial pathologies (e.g., meningitis, subarachnoid hemorrhage, tumor) are thought to result from meningeal stimulation and consequent activation of meningeal sensory fibers (Wolff 1963). Migraine headache, although not accompanied by any detectable pathology, shares certain clinical features with headaches of intracranial origin (Blau and Dexter 1981) and has also been postulated to result from activation of the meningeal sensory innervation."
"Migraine is a recurring, episodic neurological disorder characterized as a unilateral, throbbing headache that is commonly associated with a variety of other symptoms (e.g., nausea, vomiting, irritability, fatigue). Migraine pain is thought to originate from chemical irritation of the meninges, which leads to transmission of nociceptive signals from the dura mater to the brain via the so-called trigeminovascular pathway"