diaphragm

1. a MEMBRANE of MUSCLE and TENDON that separates the chest and abdominal cavities. It is covered by a SEROUS MEMBRANE and attached at the lower RIBS , breastbone ( STERNUM ) and backbone ( SPINAL COLUMN ). The diaphragm is important in breathing, when it bulges up to its resting position during exhalation. It flattens during inhalation and in so doing it reduces pressure in the thoracic cavity and helps to draw air into the lungs. 2. a rubber bowl-shaped cap used as a contraceptive with spermicidal cream. It fits inside the VAGINA over the neck of the UTERUS .