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(kris′tă, kris′tē, kris′tī″) pl. cristae [L. crista, comb (of a cock), tuft, crest] 1. A crest or ridge. 2. A fold of the inner membrane of a mitochondrion into its fluid-filled cavity.

c. ampullaris A localized thickening of the membrane lining the ampullae of the semicircular canals. It is covered with neuroepithelium containing hair cells that are stimulated by movement of the head.

c. galli A ridge on the ethmoid bone to which the falx cerebri is attached.


[Gr. kritos, fr. krinein, to separate] Suffix meaning separate.


(krī-tēr′ē-ŏn, krī-tēr′ē-ă) pl. criteria [L. criterium fr. Gr. kritērion, a means for judging] A standard or attribute for judging a condition or establishing a diagnosis.

eligibility c. Entry c.

entry c. Any of a patient’s characteristics that make him or her a candidate for enrollment in a clinical trial of a new treatment or therapeutic device. SYN: eligibility c.; inclusion c.

exclusion c. In a clinical trial, any characteristic of a patient that makes him or her a poor choice for enrollment.

inclusion c. Entry c.

outcome c. Any of the predetermined goals for quality assurance and improvement.


(krit′ĭ-kăl) [Gr. kritikos, critical] 1. Pert. to a crisis in which a dramatic change for the better or worse is probable. 2. Pert. to a potentially fatal disease. 3. Sufficient in quantity or quality to initiate or maintain a reaction, esp. a nuclear reaction. 4. Pert. to the phase of the life cycle during which cells are responsive to certain regulators. 5. Pert. to the first trimester of pregnancy when organ systems are being formed and the fetus is most vulnerable to environmental factors that may cause deformities.

critical care unit

SEE: intensive care unit.

critical incident stress debriefing, critical incident stress defusing

ABBR: CISD. Communication after a stressful care episode, such as the death of a partner or patient, a serious injury to a child, a mass casualty incident, or other disaster. A CISD is not a critique of performance, but a time for the individuals who have provided care to reflect on their experience, acknowledge and defuse stress, and plan for future events (professionally and psychologically).

critical laboratory value, critical value

A test result obtained from a clinical specimen that is so far outside the normal range that it is likely to indicate an acute risk to the health of the patient.

critical result

Critical laboratory value.

critical ...

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