Turner uses the example of the Isoma ritual among the Ndembu of northwestern Zambia to illustrate. The Isoma rite of affliction is used to cure a childless woman of infertility. Infertility is the result of a "structural tension between matrilineal descent and virilocal marriage" (i.e., the tension a woman feels between her mother's family, to whom she owes allegiance, and her husband's family among whom she must live). "It is because the woman has come too closely in touch with the 'man's side' in her marriage that her dead matrikin have impaired her fertility." To correct the balance of matrilinial descent and marriage, the Isoma ritual dramatically placates the deceased spirits by requiring the woman to reside with her mother's kin.