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(ob′stroo-ĕnt) [L. obstruens, walling up, blocking up] 1. Blocking up. 2. Anything that closes a normal passage in the body. 3. Any agent that causes obstruction.


(ŏb-troo′siv) [L. obtrudere, to thrust against] 1. Aggressively and unpleasantly noticeable. 2. Forced into one’s awareness. 3. Starkly contrasted with the environment. obtrusiveness (ŏb-troo′siv-nĕs), n.


(ob-tŭnd′) [L. obtundere, to beat against] To dull or blunt, as sensitivity or pain. SEE: levels of consciousness.


(ob-t(y)ŭ-rā′shŏn) [L. obturare, to stop up, close] Closure of a passage or opening, as of the intestines.


(ob′tŭ-rāt″ŏr) [L. obturare, to stop up, block] 1. Anything that obstructs or closes a cavity or opening. 2. A prosthetic bridge for spanning the gap in a cleft palate. 3. A device for closing the end of an instrument in order to introduce a taper-tipped device into a cavity, e.g., sigmoidoscope. 4. The obturator foramen, the obturator membrane, and other related structures such as obturator muscles, nerve, and plexus.


(ŏb-tūs′, ŏb-toos′) [L. obtusus, blunted, blunt] 1. Not pointed or acute; dull or blunt. 2. Mentally dull; stupid.


(ŏb-tū′zhŏn, ŏb-too′zhŏn) [L. obtusio, bluntness, bruising, crushing] Blunting or weakening of normal sensation.


oral contraceptive.

Occam’s razor

(ok′ămz) [William of Occam, or Ockham, Brit. Franciscan and philosopher, c. 1285–1349] The concept that the simplest explanation for a phenomenon is the best one, i.e., “what can be done with fewer (assumptions) is done in vain with more.”


(ok-sip′ĭt-ăl) [occiput + -al] Pert. to the occiput (back part of the head).

occipital area

(ok-sip′ĭt-ăl) The back of the head, comprising the occipital bone and the part of the cerebrum below the occipital bone.


(ok-sip″ĭ-tā′lĭs) [occiput] The posterior portion of the occipitofrontalis muscle at the back of the head.


(ok-sĭp″ĭ-tăl-ī-zā′shŭn) Fusion of the atlas and occipital bones.

occipital neuralgia

(ok-sip′ĭt-ăl) SEE: under neuralgia.

occipito-, occipit-

[L. occiput, stem occipit-, back of the head] Prefixes meaning occiput.


(ok-sip″ĭt-ō-sĕr′vĭ-kăl) [occipito- + cervical] Pert. to the occiput and the neck.


(ok-sip″ĭt-ō-front′ăl) [occipito- + frontal] Pert. to the occiput and the forehead. SEE: occipitofrontalis muscle.


(ok′sĭ-pŭt″) [L. occiput, the ...

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