diaphragm

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diaphragm

 [di´ah-fram]
1. the musculomembranous partition separating the thoracic and abdominal cavities. On its sides it is attached to the six lower ribs, at its front to the sternum, and at its back to the spine. The esophagus, aorta, vena cava, and numerous nerves pass through the diaphragm. When relaxed it is convex, but it flattens as it contracts during inhalation, thereby enlarging the chest cavity and allowing for expansion of the lungs. See also respiration.
2. any separating membrane or structure.
3. a disk with one or more openings or with an adjustable opening, mounted in relation to a lens or source of radiation, by which part of the light or radiation may be excluded from the area.
contraceptive diaphragm a shallow dome-shaped disk used as a contraceptive, made of a soft plastic material such as latex. Its anterior lip fits behind the symphysis pubis and its posterior lip rests in the posterior fornix. It is used with a spermicide to prevent entrance of spermatozoa into the cervical os. See also contraception.
pelvic diaphragm the portion of the floor of the pelvis formed by the coccygeus muscles and the levator ani muscles, and their fascia.
polyarcuate diaphragm one showing abnormal scalloping of margins on radiographic visualization.
urogenital diaphragm a traditional but no longer valid concept that superior and inferior layers enclose the sphincter urethrae and deep transverse perineal muscles and together form a musculomembranous sheet that extends between the ischiopubic rami.
vaginal diaphragm contraceptive diaphragm.

di·a·phragm

(dī'ă-fram),
1. The musculomembranous partition between the abdominal and thoracic cavities. Synonym(s): diaphragma (2) , interseptum, midriff, phren (1)
2. A thin disc pierced with an opening, used in a microscope, camera, or other optic instrument to shut out the marginal rays of light, thus giving a more direct illumination.
3. A flexible ring covered with a domed sheet of elastic material used in the vagina to prevent pregnancy.
4. In radiography, a grid (2) or a lead sheet with an aperture.
[G. diaphragma]

diaphragm

/di·a·phragm/ (di´ah-fram)
1. the musculomembranous partition separating the abdominal and thoracic cavities and serving as a major muscle aiding inhalation.
2. any separating membrane or structure.
3. a disk with one or more openings or with an adjustable opening, mounted in relation to a lens or source of radiation, by which part of the light or radiation may be excluded from the area.
4. a device of molded rubber or other soft plastic material, fitted over the uterine cervix before intercourse to prevent entrance of spermatozoa.diaphragmat´ic

contraceptive diaphragm  diaphragm (4).
pelvic diaphragm  the portion of the floor of the pelvis formed by the coccygeal and levator ani muscles and their fasciae.
polyarcuate diaphragm  one showing abnormal scalloping of the margins on radiographic visualization.
Potter-Bucky diaphragm  see under grid.
respiratory diaphragm  diaphragm (1).
urogenital diaphragm  traditional but no longer valid concept that fascial layers enclose the sphincter urethrae and deep transverse perineal muscles and together form a musculomembranous sheet that extends between the ischiopubic rami.
vaginal diaphragm  diaphragm (4).

diaphragm

(dī′ə-frăm′)
n.
1. Anatomy A muscular membranous partition separating the abdominal and thoracic cavities and functioning in respiration. Also called midriff.
2. A membranous part that divides or separates.
3. A thin disk, especially in a microphone or telephone receiver, that vibrates in response to sound waves to produce electric signals, or that vibrates in response to electric signals to produce sound waves.
4. A contraceptive device consisting of a thin flexible disk, usually made of rubber, that is designed to cover the uterine cervix to prevent the entry of sperm during sexual intercourse.
5. A disk having a fixed or variable opening used to restrict the amount of light traversing a lens or optical system.

di′a·phrag·mat′ic (-frăg-măt′ĭk) adj.
di′a·phrag·mat′i·cal·ly adv.

diaphragm

[dī′əfram]
Etymology: Gk, diaphragma, partition
1 (in anatomy) a dome-shaped musculofibrous partition that separates the thoracic and abdominal cavities. The convex cranial surface of the diaphragm forms the floor of the thoracic cavity; the concave surface forms the roof of the abdominal cavity. This partition is pierced by various openings through which pass the esophagus and inferior vena cava. The diaphragm aids respiration by moving up and down. During inspiration it moves down and increases the volume of the thoracic cavity. During expiration it moves up, decreasing the volume. During deep inspiration and expiration the range of diaphragmatic movement in the adult is about 30 mm on the right side and about 28 mm on the left side. The height of this structure also varies with the degree of distension of the stomach and the intestines and with the size of the liver. It is innervated by the phrenic nerve from the cervical plexus.
3 (in optics) an opening that controls the amount of light passing through an optical network.
4 a thin, membranous partition, as that used in dialysis.
5 (in radiography) a metal plate with a small opening that limits the diameter of the radiographic beam. diaphragmatic, adj.
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Diaphragm

diaphragm

A contraceptive device consisting of a thin membranous disk, typically constructed of rubber, which is designed to cover the cervical os and prevent the entry of sperm during sexual intercourse.

diaphragm

Gynecology A barrier contraceptive consisting of a thin flexible rubber disk that covers the uterine cervix to prevent the entry of sperm during sexual intercourse

di·a·phragm

(dī'ă-fram) [TA]
1. The musculomembranous partition between the abdominal and thoracic cavities.
Synonym(s): diaphragma (2) [TA] , midriff.
2. A thin disc pierced with an opening, used in a microscope, camera, or other optic instrument to shut out the marginal rays of light, thus giving a more direct illumination.
3. A flexible ring covered with a dome-shaped sheet of elastic material placed in the vagina to prevent pregnancy.
4. radiography A grid (2).
[G. diaphragma]

diaphragm

(di'a-fram?) [Gr. diaphragma, a partition]
1. A thin membrane as is used for dialysis.
2. In microscopy, an apparatus located beneath the opening in the stage and permitting regulation of the amount of light passing through the object.
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CONTRACEPTIVE DIAPHRAGM
3. A rubber or plastic cup that fits over the cervix uteri, used for contraceptive purposes. See: illustration
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MOVEMENT OF RIB CAGE AND DIAPHRAGM DURING RESPIRATION: A. Inspiration: Air drawn into lungs; B. Expiration: Air forced out of lungs
4. The dome-shaped skeletal muscle that separates the abdomen from the thoracic cavity with its convexity upward. 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 glands, and the kidneys; the right side is slightly higher than the left. See: illustration; Boerhaave syndrome

Bucky diaphragm

See: Bucky, Gustav P.

hernia of diaphragm

A congenital or traumatic protrusion of abdominal contents through the diaphragm.

pelvic diaphragm

Pelvic floor.

Potter-Bucky diaphragm

Bucky diaphragm.

slit diaphragm

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 diaphragm

The urogenital trigone, or triangular ligament. A musculofascial sheath that lies between the ischiopubic rami, it is superficial to the pelvic diaphragm. In males it surrounds the membranous urethra; in females, the vagina.
illustration

diaphragm

1. The dome-shaped muscular and tendinous partition that separates the cavity of the chest from the cavity of the abdomen. When the muscle contracts the dome flattens, thereby increasing the volume of the chest.
2. Any partitioning structure, such as the iris diaphragm of the eye.

diaphragm

  1. a sheet of tissue present only in mammals, that separates the thorax from the abdomen. It consists mainly of muscle and tendons, and has openings through which the oesophagus, blood vessels and nerves pass. Its flattening from a convex position projecting into the thorax is an important aspect of the expansion of the lungs as inspiration takes place. See BREATHING.
  2. a hemispherical rubber cap fitted inside the vagina over the neck (cervix) of the uterus and acting as a contraceptive for BIRTH CONTROL.

Diaphragm

The thin layer of muscle that separates the chest cavity containing the lungs and heart from the abdominal cavity containing the intestines and digestive organs.
The diaphragm.
Figure 1: The sites of the main nerve centres and descending pathways in the brain and spinal cord that control voluntary movement, represented in diagrammatic sections.
Figure 2: Ascending nerve pathways and proprioceptive reflex arcs, represented in diagrammatic sections of the brain and spinal cord. Shown on the right: those serving the sensations listed. Shown on the left: reflex pathways for skeletal muscle control. (A) From a muscle spindle, to a synapse with an alpha motor neuron, and a branch to the brain. (B) From a tendon organ, inhibitory branch (broken line) to an alpha motor neuron, and a branch to the brain.
Figure 3: The nervous system.

diaphragm

the musculotendinous partition between the thoracic and abdominal cavities, penetrated by the lower end of the oesophagus, aorta, vena cava and other vessels and nerves. Attached around its periphery to the ribcage and the vertebral column. The main muscle of breathing, controlled by rhythmic impulses from the brain stem via the phrenic nerves. Contraction flattens it, expanding the thorax, reducing the pressure inside the lungs and causing inspiration; in relaxation, it rises again to a 'dome', allowing passive expiration (this diaphragmatic or abdominal breathing is the normal pattern at rest: the abdomen protrudes as the diaphragm is lowered). Lavish blood supply and high oxidative capacity enable the diaphragm to sustain the major increase in the work of breathing during exercise, but at high intensity its demand for blood competes with that of the exercising muscles. Fatigue of the diaphragm (and of other respiratory muscles) has been shown to contribute to exercise limitation. Unique among skeletal muscles in maintaining its activity continuously for a lifetime under involuntary control, yet which can, within limits, be voluntarily overridden. See Figure 1, Figure 2, Figure 3.

diaphragm

1. In optics, an aperture generally round and of variable diameter placed in a screen and used to limit the field of view of a lens or optical system (field stop). It also limits stray light (light stop). Syn. stop; aperture-stop. 2. In anatomy, a dividing membrane.

di·a·phragm

(dī'ă-fram) [TA]
1. [TA] Musculomembranous partition between abdominal thoracic cavities.
2. In radiography, a grid (2) or a lead sheet with an aperture.
See: collimator
3. A thin disc pierced with an opening, used in a microscope, camera, or other optic instrument to shut out the marginal rays of light, thus giving a more direct illumination.
[G. diaphragma]

diaphragm (dī´əfram),

n 1. a musculotendinous partition that separates the thorax and abdomen.
n 2. a metal barrier plate, often of lead, pierced with a central aperture so arranged as to limit the emerging, or useful, beam of roentgen rays to the smallest practical diameter for making radiographic exposures. See also collimation; collimator; distance, cone.
diaphragm, lead,
n a collimating device with a small opening, designed to limit the size of the outgoing x-ray beam. It is usually made of lead one-eighth of an inch thick and located between the position-indicating device and the radiographic tube itself.

diaphragm

1. the musculomembranous partition separating the thoracic and abdominal cavities. On its sides, it is attached to the caudal ribs; ventrally to the sternum; at the back, to the spine. The esophagus, the aorta and vena cava, and nerves pass through the diaphragm. When relaxed, the diaphragm is convex but it flattens and moves caudally as it contracts during inhalation, thereby enlarging the chest cavity and allowing for expansion of the lungs. See also respiration.
2. any separating membrane or structure.
3. a disk with one or more openings or with an adjustable opening, mounted in relation to a lens, by which part of the light may be excluded from the area.
See also diaphragmatic.

Potter-Bucky diaphragm
see Potter-Bucky grid.
lightbeam diaphragm
an adjustable diaphragm which is used to cone down a light beam that indicates the dimensions of an x-ray beam and marks the position of the central ray.
pelvic diaphragm
the portion of the caudal wall of the pelvis formed by the coccygeus muscles, the levator ani muscles and fascia.
slit diaphragm
see filtration membrane.
urogenital diaphragm
the musculomembranous layer superficial to the pelvic diaphragm, extending between the ischiopubic rami and surrounding the urogenital ducts.