A 40-year-old woman comes to the emergency. For

the first time in her life, she experiences a severe migraine attack

accompanied, in addition to the typical headache, by nausea, vomiting,

photophobia (light-headedness) and phonophobia (noise intolerance). Migraine

can be caused by a number of factors and very often a combination of these. One

of the factors involved may be the involvement of the vasa vasorum and nervi

vasorum and the altered reactivity of the vessels of the central nervous

system. In which layer of the arterial wall are the vasa and nervi vasorum

found in normal healthy blood vessels?