(dī'ă-fram‵ )

[L. diaphragma, fr. Gr. diaphragma, stem diaphragmat-, a partition]

1. A thin membrane as is used for dialysis.
2. In microscopy, an apparatus that is located beneath the opening in the stage and permits regulation of the amount of light passing through the object.
3. A rubber or plastic cup that fits over the cervix uteri, used for contraceptive purposes.

   SEE: illus..

4. The dome-shaped skeletal muscle that separates with its upward convexity the abdomen from the thoracic cavity. It contracts to promote inhalation, flattening downward and permitting the lungs to expand . It relaxes to promote exhalation, rising to its dome-shaped position and compressing the lungs.

The origin of the diaphragm is the xiphoid process, the lower six costal cartilages, and the lumbar vertebrae. The diaphragm is directly superior to the liver, the stomach, the spleen, the adrenal gland s, and the kidneys; the right side is slightly higher than the left.

SEE: illus. ; Boerhaave syndrome .

Bucky d.

SEE: under Bucky, Gustav P..

pelvic d.Pelvic floor.

Potter-Bucky d.Bucky diaphragm.

slit d.A gap between the foot processes of podocytes in the renal glomerulus, composed of a filter made of proteins that holds large molecules within the plasma but allows smaller soluble chemicals to pass with water into the urine.

urogenital d.The perineal membrane, a part of the complex floor of the pelvis. It is conceived of as a musculofascial sheath that lies between the ischiopubic rami and is superficial to the pelvic diaphragm. In males it surrounds the membranous urethra; in females, the vagina.

illus.