| spongy spot | An area in the external acoustic meatus where a number of minute blood vessels enter from the mastoid bone. Synonym: spongy spot, zona vasculosa. (05 Mar 2000) |
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| spongy substance | Bone in which the spicules or trabeculae form a three-dimensional latticework (cancellus) with the interstices filled with embryonal connective tissue or bone marrow. Synonym: substantia trabecularis, cancellous bone, spongy bone, spongy substance, trabecular bone. (05 Mar 2000) |
| spongy urethra | The portion of the male urethra, about 15 cm in length, which traverses the corpus spongiosum. Synonym: pars spongiosa urethrae masculinae, pars cavernosa, penile urethra, spongy part of the male urethra. (05 Mar 2000) |
| spontaneity | Origin: Cf. F. Spontaneite. 1. The quality or state of being spontaneous, or acting from native feeling, proneness, or temperament, without constraint or external force. "Romney Leigh, who lives by diagrams, And crosses not the spontaneities Of all his individual, personal life With formal universals." (Mrs. Browning) 2. <biology> The tendency to undergo change, characteristic of both animal and vegetable organisms, and not restrained or cheked by the environment. The tendency to activity of muscular tissue, including the voluntary muscles, when in a state of healthful vigor and refreshment. Source: Websters Dictionary (01 Mar 1998) |
| spontaneous | 1. Proceding from natural feeling, temperament, or disposition, or from a native internal proneness, readiness, or tendency, without constraint; as, a spontaneous gift or proportion. 2. Proceeding from, or acting by, internal impulse, energy, or natural law, without external force; as, spontaneous motion; spontaneous growth. 3. Produced without being planted, or without human labour; as, a spontaneous growth of wood. Spontaneous combustion, combustion produced in a substance by the evolution of heat through the chemical action of its own elements; as, the spontaneous combustion of waste matter saturated with oil. Spontaneous generation. <biology> See Generation. Synonym: Voluntary, uncompelled, willing. Spontaneous, Voluntary. What is voluntary is the result of a volition, or act of choice; it therefore implies some degree of consideration, and may be the result of mere reason without excited feeling. What is spontaneous springs wholly from feeling, or a sudden impulse which admits of no reflection; as, a spontaneous burst of applause. Hence, the term is also applied to things inanimate when they are produced without the determinate purpose or care of man. "Abstinence which is but voluntary fasting, and . . . Exercise which is but voluntary labour." "Spontaneous joys, where nature has its play, The soul adopts, and owns their firstborn away." (Goldsmith) Sponta"neously, Sponta"neousness. Origin: L. Spontaneus, fr. Sponte of free will, voluntarily. Source: Websters Dictionary (01 Mar 1998) |
| spontaneous abortion | The sudden unplanned evacuation of the uterus. (27 Sep 1997) |
| spontaneous agglutination | The non-specific clumping of organisms in saline related to lack of polar groups in electrolyte solution. (05 Mar 2000) |
| spontaneous amputation | Amputation as the result of a pathologic process rather than external trauma. (05 Mar 2000) |
| spontaneous breech extraction | Delivery of a foetus in the breech presentation without extraction by the obstetrician. (05 Mar 2000) |
| spontaneous cephalic delivery | Unassisted expulsion of a foetus that presents by the head. (05 Mar 2000) |
| spontaneous combustion | A circumstance where a substance or organism takes fire and burns without an exogenous source. Spontaneous human combustion differs from preternatural human combustibility in that in the latter, some spark or trivial flame sets the fire and the body tissues, which have a greatly enhanced inflammability, continue to undergo incineration without any external heat source or combustible materials. (bergman na. Spontaneous human combustion: its role in literature and science. Pharos 1988;fall;51(4):18-21) (12 Dec 1998) |
| spontaneous correction of placenta previa | The upward "migration" of the placenta away from the internal os by the differential growth rates of upper and lower uterine segments. (05 Mar 2000) |
| spontaneous emission | <radiobiology> Radiation randomly emitted by excited atoms or ions. Contrast with stimulated emission. (09 Oct 1997) |
| spontaneous evolution | The unaided delivery of the foetus from a transverse lie. (05 Mar 2000) |
| spontaneous fracture | A fracture occurring without any external injury. (05 Mar 2000) |