WRIST-JOINT (NORMAL ANATOMY). 



1505 



Besides stridulation, and humming, some 

 insects, such as bees, emit a cry, or, as the 

 French entomologists term it, piaiilcment. 

 M. (lonreati supposes this variety of voice to 

 be used, wlien bees swarm preparatory to tlieir 

 emigration. He remarks that those insects 

 which produce the sound by friction are not 

 singers, but musicians ; and that insects in 

 general make use of their voices to communi- 

 cate certain ideas and sensations. 



Fig. 923. 



Thoracic spiracle of the Humble Bee (Bomb/is 

 terrestris). 



In insects we find a great diversity of beau- 

 tifully contrived mechanism for the modula- 

 tion of sound, all answering the same end in 

 the economy of these countless nij'riads of 

 minute beings. 



BIBLIOGRAPHY . J. Casserii Placent. De Vocis 

 Organis, Ferrar, 1600, fol. Hieron Fabricii, Oper. 

 onin. Lips. 1637. fol. Aristotle, tom. ii. p. 2M. 

 Galen, tom. iv. chap xi. Dodart, Me'm. de 1'Acad. 

 de Paris, 1700, 1706, 1707. Wallis (/.)', De Lo- 

 quela, 1740. Ferrein, ibid, 1741. Bet-tin, Nouveaux 

 Sys. de la Yoix, 1745. Herrissant, Me'm. de 1'Acad. 

 de Paris, 1753. Sieller, Beschreibung von Soridcr- 

 barcn Meerthieren, Halle, 1753. Busch,De Meeha- 

 nismo Organi Vocis,Groning. 1770. Pallas, Spicilegia 

 Zoolog. Berolini, 1777, 1778. Vicq-D'Azyr, Me'm. 

 de 1'Acad., 1779. Camper, Phil. Trans., 1779. Votjel 

 (R. A.), De Larynge Humana; et Holler, Element. 

 Physiol. torn. iii. vol. ii., 1787. Amman (J. C.), 

 17'JO. Hitm/ioldt and Boiiftland, Eecucil d'Observ. de 

 Zool., Paris, 1805, fol. Blumeiihach, Handbuch der 

 YcTgleichenden Anat. Gottingen, 1805. Dutrochet, 

 Essai d'une Nouvelle Theorie de la Yoix Humaine. 

 Paris, 1806. Young (Dr. T.) Lectures on Natural 

 Philosophy, vol. iv., 1807. Yarrell, Linn. Trans, 

 vol. xvi. Gockel, De \ r oce Animal. Mix. Acad. Nat. 

 Cur. Wolff, Diss. Anat. de Organo Vocis Mam- 

 malium. lierol. 1812. Savart, Annal. et de Chcmie 

 de 1'hysique, tom. 24. 26. 29. 32. Liscovins, Theorie 

 der Stimme. Leipz. 1814. Maymdie, Pre'cis Ele'- 

 ment. de Phys. Pen-unit, Me'm. pour servir a 

 1'Histoire des Anim. torn. iii. Biot, Precis Element, 

 dc Physique, Paris, 1824. Chladni, in Gilbert's Ann. 

 76. p. 187. Bennati, Eecherches sur le Me'canisme 

 dc la Yoix Humaine. Paris, 1832. Willis, Trans. 

 Phil. Soc. Cambridge, 1832. Sir C. Bell, Phil. Trans. 

 1836. (?Mrft,Yergl. Anat. der Haussiiugethiere, iNJii. 

 Goure.au, I'.ssai sur la Stridulation des Insectes. Ann. 

 dc la Socie'tc Entomologique. Paris, 1837. Burmeister 

 (//.), On the Cause of the Sound produced by 



VOL. IV. 



Insects in Flying, Taylor's Scientific Memoirs, 

 vol. i. 1837. JMeckel, Anat. Compare'e, tome dixieme. 

 Paris, 1838. He.nle, Des Kehlkopfs der Eeptilien. 

 Leipzig, 1839. Carats. Lehrbuch der Verchlichenden 

 Zootomie, Bd. 1. Wayncr, Lehrbuch tier Yrr- 

 chleichenden Anat. Tree Iran us, Erscheinungeii und 

 Gesetze Organischen. Bd. 2. Cwier, Anat. C'nin- 

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 Miiller, Elements of Physiol. by Bahj, p. 1002. 



(John Bishop.') 



WORMIANA OSSA (vide. CRANIUM). 



WRIST-JOINT (Hadio-carjml Articula- 

 tion'), NORMAL ANATOMY OF THE. The ar- 

 ticulation of the wrist results from the union 

 of the bones of the lore-arm with those of the 

 hand, and is constituted by the contact of the 

 lower surfaces of the radius and of the trian- 

 gular interarticular cartilage with the sca- 

 phoid, lunar, and cuneiform bones of the 

 carpus. The radius and the triangular fibro- 

 cartilage accordingly present a uniformly 

 smooth and slightly concave surface, whilst 

 the first three bones of the carpus afford a 

 surface which is as uniformly convex. The 

 transverse measurement of these articular 

 surfaces is greater than the antero-posterior, 

 since the former averages one inch and a half 

 in the adult male, whilst the latter scarcely 

 exceeds three quarters of an inch. 



In this joint are found all the anatomical 

 dispositions which characterize other arthro- 

 dial articulations: the bones are invested with 

 cartilage, lined by a synovia I membrane, and 

 present smooth surfaces which deviate but 

 slightly from being planiform ; and lastly, the 

 ligaments connecting the osseous surfaces are 

 so disposed, as to admit of all the free gliding 

 motions which are indispensable to the hand 

 as an organ of touch and of prehension. 



It is proposed in this article to describe, 

 seriatim, the different structures which enter 

 into the composition of the radio-carpal 

 articulation, with their relative anatomy, but 

 for a detailed account of the surgical anatomy 

 of the region of the wrist, the reader is re- 

 ferred to the article Hand, where this subject 

 has been fully entered into. 



I. The Bones which constitute the wrist-joint. 

 a. The Radius. The lower end of the 

 radius, which is of a quadrilateral form, is 

 curved so as to present a concavity ante- 

 riorly, and a convexity in the opposite 

 direction. On its different aspects various 

 objects of interest present themselves to view, 

 which may be thus enumerated: Anteriorly 

 is seen a smooth surface, to which the ten- 

 dons of the flexor muscles, surrounded by 

 their synovia! sheath, arc applied ; posteriorly, 

 a series of depressions and irregular elevations 

 are observable, the former of which indicate 

 the course of different tendons passing to the 

 hand. Of these depressions the most ex- 

 ternal is a broad but shallow groove, which 

 lodges the tendons of the radial extensors of 

 the carpus: to its inner side, but separated 

 from it by a well-marked ridge, is a narrow 

 deep groove, which runs obliquely down- 

 wards and outwards, and transmits in this 



5 D 



