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.
Oxygen therapy is one of the best treatments to stop a cluster headache. Oxygen therapy relieves headache pain within 15 minutes in more than 7 out of 10 people who use it. It works best when started right when a cluster headache starts. But you need to repeat the treatment when the next headache begins.