Pl. -æ. Also trabeculum, pl. -a; trabeculus, pl. -i; and in anglicized forms trabecle, trabecule. [L. trabecula, trabicula, dim. of trabs beam; the forms in -um and -us are mod.L. variants.] A structure in an animal or plant resembling a small beam or bar.
spec. a. Anat. and Zool. Each of the plates of bony substance forming the cancellated tissue of a bone; any slender band of tissue extending like a cross-bar across a cavity, as of the heart (trabeculæ carneæ), or through the substance of a soft organ, as the spleen or kidney; each of two cartilaginous bars (trabeculæ cranii) in front of the pituitary body in the embryo, which coalesce and develop into part of the cranium; each of the calcareous plates connecting the dorsal and ventral walls in echinoderms; each of a pair of appendages on the head in front of the antennæ in certain bird-lice. b. Bot. A projection extending across the cell-cavity in the ducts of some plants, or across the cavity of the sporangium in mosses and other cryptogams.
1866. Treas. Bot., Trabecula (adj. Trabeculate), a cross-bar; as in the teeth of many mosses.
1873. T. H. Green, Introd. Pathol. (ed. 2), 137. This tissue, like bone, is made up of trabeculæ and medullary spaces.
1874. Coues, Birds N. W., 611. Divided … by a cartilaginous trabeculum, which is thrown across from the posterior side to the anterior apex of the base of the pyramid.
1875. Sir W. Turner, in Encycl. Brit., I. 853/2. The interior of a bone … is made up of thin delicate plates or bars, or trabecles, which intersect each other at various angles, and form … the spongy or cancellated tissue.
1875. Bennett & Dyer, trans. Sachs’ Bot., II. iv. 413. Both kinds of sporangia [in Isoëtes] are imperfectly segmented by threads of tissue [Trabeculæ] which cross from the ventral to the dorsal side.
1890. Billings, Med. Dict., Trabecula cinerea, soft commissure of the brain.
Hence Trabecular a., pertaining to or of the nature of a trabecula; composed of or furnished with trabeculæ; Trabecularism, trabecular condition, trabeculation; Trabeculate, -ated adjs., furnished with or having trabeculæ; Trabeculation, formation of trabeculæ, trabeculated condition.
1822–34. Good’s Study Med. (ed. 4), III. 164. A cystic form [of cataract] without pus,… a siliquose and a *trabecular.
1847–9. Todd’s Cycl. Anat., IV. 773/1. The trabecular tissue consists of … cylindrical fibres.
1891. Cent. Dict., *Trabecularism, in anat., a coarse reticulation, or cross-barred condition, of any tissue.
1866. *Trabeculate [see TRABECULA].
1876. trans. Wagner’s Gen. Pathol. (ed. 6), 359. They … unite by opposite processes into networks, form *trabeculated membranes.
1898. Allbutt’s Syst. Med. V. 182. Cavities … traversed by tough septa and bridles … are … described as trabeculated.
1900. Lancet, 5 May, 1275/2. *Trabeculation of the bladder.
1904. Jrnl. R. Microsc. Soc., Dec., 636.
