‖ rotula
(ˈrɒtjʊlə)
Pl. usu. rotulæ (ˈrɒtjʊliː).
[L. rotula, dim. of rota wheel.]
1. Anat. a. The knee-cap, patella.
| c 1400 Lanfranc's Cirurg. 177 A round boon..clepid rotula, & of summen it is clepid þe yȝe of þe knee. 1597 A. M. tr. Guillemeau's Fr. Chirurg. p. xij b/1 That which is rotundelye elevatede, is called Rotula, or the shive of the knee. 1715 S. Sewall Diary 2 July, I..was grievously surpris'd to find Hannah fallen down the Stairs again, the Rotula of her Left Knee broken. 1741 Monro Anat. Nerves (ed. 3) 291 The Substance of the Rotula is cellular. 1803 J. Barclay New Anat. Nomencl. 127 Those parts in the sacral extremities..are the tibia, fibula, poples, and rotula. |
b. The point of the elbow.
| 1760–72 H. Brooke Fool of Qual. (1809) I. 98 The ball..lodged on the rotula of my left arm. 1900 Daily News 3 July 3/4 The rotula of the elbows form big balls like knots on a crabtree stick. |
2. a. One of five radial pieces forming part of the oral skeleton of sea-urchins.
| 1877 Huxley Anat. Inv. Anim. ix. 576 Superiorly, the epiphyses of each pair of alveoli are connected by long radial pieces—the rotulæ, articulated with their edges. Ibid., The radii and rotulæ are ambulacral. 1888 Rolleston & Jackson Anim. Life 560 This apparatus consists of an interradial portion..and of a radial portion—viz. the rotula and the radii. |
b. A calcareous formation in the integument of some holothurians.
| 1888 Rolleston & Jackson Anim. Life 550 The calcareous deposits of the body are as a rule represented only by scattered spicules.., by wheels (= rotulae), e.g. in Chirodota,..or variously shaped plates. |
3. A genus of sea-urchins.
| 1753 Chambers' Cycl. Suppl. s.v., The characters of the rotulæ are, that they are flat shells in form of a cake. |
4. (See quot. 1760.)
| 1760 J. Ferguson (title), The Description and Use of the Astronomical Rotula, shewing the Change and Age of the Moon, the Motions and Places of the Sun, Moon, and Nodes in the Ecliptic [etc.]. 1883 Blackw. Mag. Aug. 258 Rotulas, orreries, dials, everything he could think of, his patient hands elaborated. |
Hence ˈrotulad adv. (See first quot.)
| 1803 J. Barclay New Anat. Nomencl. 166 In the sacral extremities,.. Rotulad will signify towards the rotular aspect. 1808 ― Muscular Motions 435 The vagina..is in passing the joint extended rotulad and poplitead of the centre of motion. |