amnion. the innermost fetal membrane, which forms a sac filled with amniotic fluid that surrounds the embryo and later the fetus; as it enlarges it gradually obliterates the chorionic cavity and enfolds the umbilical cord. Called also bag of waters.
cluster breathing. cluster breathing. a breathing pattern in which a closely grouped series of respirations is followed by apnea. The activity is associated with a lesion in the lower pontine region of the brainstem. See also Biot's respiration, Cheyne-Stokes respiration.
How to treat it: Due to the quick onset of severe pain, cluster headaches are tough to treat. Inhaling pure oxygen through a mask can help a majority of sufferers, providing relief within 15 minutes. Medications called triptans âavailable as an injection, nasal spray, or tabletâcan also help treat cluster headaches.