The thoraco-abdominal diaphragm separates the chest cavity from the abdomen. It attaches to the xiphoid process of the ribcage and to the vertebral column, and essentially separates the top half of your body from the lower half. It is the main muscle used in respiration (breathing).

When the diaphragm is at rest, it curves upwards in the middle. When you inhale, the diaphragm contracts, pulling its center down, and consequently expanding the chest cavity. The lungs 'stick' to the inside of the chest cavity, so when it expands, so do they, sucking in air. At the same time this stimulates the stomach and liver to help digestion along. When the diaphragm relaxes it squeezes the air back out of your lungs. This action alone is enough to keep you well oxygenated, although other muscles (such as the intercostals) will become involved if you need to breath more heavily, or speak above a whisper. The diaphragm is innervated by the phrenic nerve.

Hiccups are the result of muscle spasms in this diaphragm.

Also, of course, a latex disc around a spring steel ring that is used as a barrier method of contraception, usually augmented with the application of a spermicide.

The diaphragm can be extremely effective if used conscientously and correctly, and if the diaphragm is fitted correctly. The diaphragm has to completely cover the cervix, and has to be prescribed and fitted by a medical professional. If the woman gains or loses more than 10 pounds, or becomes pregnant, the diaphragm must be refitted.

Diaphragms have about an 85% success rate at preventing pregnancy--largely due to some specific things that have to be done when it is used. It can be inserted 2 to 3 hours before intercourse, but must be left in 6 to 8 hours afterwards to be sure the spermicide is effective. If you have intercourse again in that period additional spermicide must be applied with an applicator. Diaphragms will become ineffective after a few years and should be replaced regularly. Every time it is used it should be checked for tears or pinholes (since it is natural latex, there can be flaws which can cause holes). If the diaphragm is not inserted correctly, it is possible that the penis will get behind it, and possibly cause it to be ineffective (and painful for both parties).

Some women (and men) may become sensitive to the spermicide or latex in diaphragms, just like you might with a condom.

The chief advantages to the diaphragm is that it is a temporary form of birth control, has a lower risk of side effects than the Pill, and somewhat reduces the risk of STDs. It's main disadvantages is that it completely wrecks spontaneity.

Di"a*phragm (?), n. [L. diaphragma, Gr. , fr. to fence by a partition wall; through + , , to fence, inclose; prob. akin to L. fareire to stuff: cf. F. diaphragme. See Farce.]


A dividing membrane or thin partition, commonly with an opening through it.

2. Anat.

The muscular and tendinous partition separating the cavity of the chest from that of the abdomen; the midriff.

3. Zool.

A calcareous plate which divides the cavity of certain shells into two parts.

4. Opt.

A plate with an opening, which is generally circular, used in instruments to cut off marginal portions of a beam of light, as at the focus of a telescope.

5. Mach.

A partition in any compartment, for various purposes.

Diaphragm pump, one in which a flexible diaphragm takes the place of a piston.


© Webster 1913.

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