In the nozzle, the water is focused into a thin beam by a jewel orifice. Constant mass flow is achieved by sonic flow through an orifice. At the summit of the glans is the slit-like vertical external urethral orifice. Where D is the diameter of the orifice holes. Most IDI systems use a single orifice injector. This needle is held in the fuel flow orifice. Atomization is accomplished by forcing a molten metal stream through an orifice at moderate pressures. Where "d" is the orifice diameter. The ileum terminates at the cecocolic junction of the large intestine forming the ileal orifice. On its first attempt, a clogged igniter orifice prevented ignition. Later the derivative term was added by a further bellows and adjustable orifice. The appearance of the fetal head at the vaginal orifice is termed the "crowning". The ionized xenon also exits out of the orifice. Water clocks kept time by the rate of water flowing through an orifice. Stricture, or narrowing of the vaginal orifice was reported in 12-15% of the cases.