REN. 



231 



muscles that effect pronation, fix the condyles 

 of the humerus by any means, and then re- 

 peat the examination of these angles. 



Pronation and supination may, however, 

 be carried far beyond this limit of the radial 

 motion ; aided by powerful rotation of the 

 humerus inwards and outwards respectively, 

 the surfaces will attain to complete opposition 

 of direction, or 180 degrees of intervening 

 angle, and even to a variable distance beyond 

 this which is, on an average, almost another 

 quadrant. 



It deserves also to be noticed, that these 

 movements are often converted into rotation 

 around the axis of the lower part of the 

 forearm and wrist, by a somewhat similar 

 humeral movement. For example, simul- 

 taneously with pronation, the lower end of the 

 humerus is carried outwards and upwards, and 

 a similar deviation is thus impressed on the 

 ulna articulated with it, which extending to 

 its lower extremity, results in the rotation of 

 this part of the limb ; i. e. in the completion 

 of pronation, without the usual advance of 

 the inner border of the forearm towards the 

 median line of the body. 



Dislocations of these joints. At the upper of 

 the two radio-ulnar articulations either bone 

 may be thrown out of its place in several 

 directions. Displacements of the ulna, how- 

 ever, chiefly affecting the elbow joint into 

 which it so largely enters, are included 

 amongst those of this part ; and though those 

 of the radius are, both in nature and effects, 

 accidents of the radio-ulnar articulation, in 

 practice it is very difficult to avoid considering 

 together injuries which have so close a re- 

 lation, albeit, strictly speaking, an accidental 

 one. Hence the reader is referred for these 

 to the article " Abnormal Conditions of the 

 Elbow-joint." 



At the lower joint the radius and ulna may 

 be displaced from each other by external 

 force, or by the violent action of the muscles 

 in extreme pronation or supination : but the 

 latter is a very rare occurrence. Looking to this 

 articulation only, it might be difficult to define 

 which bone was dislocated : whether, for in- 

 stance, the ulna was " dislocated backwards," 

 or the radius " dislocated forwards," since, 

 in such a case, either of these phrases would 

 equally express their altered relation to each 

 other. It is most convenient to consider this 

 question determined by the condition of the 

 neighbouring wrist joint, and to instance those 

 cases as dislocations of the radius where the 

 extremity of this bone is located unnaturally 

 forwards or backwards, both as regards the 

 carpus and head of the ulna. And, similarly, 

 where the wrist and radius preserve their 

 ordinary relation, but the lower end of the 

 ulna is displaced with respect to both ; here it 

 will be better to consider the ulna as the 

 luxated bone, even though the accidents might 

 sometimes resemble each other in their causes 

 as well as mode of production. 



The dislocation of the radius forwards is 

 easily recognized by the styloid process of 

 this bone and the trapezium no longer lying 



in the same vertical line ; and by the situation 

 of the extremity of the radius in front of the 

 bones of the carpus, causing an unnatural 

 prominence there. The luxation backwards 

 would appear to be almost unknown, a reversal 

 of these signs would indicate it. In both, the 

 relative position of the ulna and wrist is little 

 affected. 



In the dislocation of the ulna, the ordinary 

 connection of the hand and radius being kept 

 up, the pronation or supination of the limb 

 becomes a feature of a very striking kind. 

 The signs of the luxation backwards are ex- 

 treme pronation, the head of the ulna pro- 

 jecting beneath the skin at the back of the 

 forearm, and the styloid process of this bone 

 occupying a line posterior to the border of 

 the wrist or the cuneiform bone. The dis- 

 location forwards is of extreme rarity, but 

 the above marks, mutatis mutandis, would 

 leave little room for doubt as to the nature 

 of the accident. 



The diseases of these articulations offer no 

 peculiarities which deserve a separate de- 

 scription. 



( William Brinton.) 



REN* THE KIDNEY (Gr. 

 Germ. Niere ; Fr. Rein ; It. Ren}. The 

 kidney is a double gland, having for its office 

 the secretion of a liquid which in common 

 language is called urine. Since the time of 

 Malpighi, the structureof this organ has excited 

 in a more than ordinary degree the interest ot 

 the anatomist and the physiologist ; but this 

 interest has been much increased by the re- 

 searches of Mr. Bowman, whose admirable 

 paper on the " Structure and Use of the Mal- 

 pighian bodies of the Kidney f," while it has 

 placed the kidney in the list of those organs 

 whose anatomy is most clearly demonstrated, 

 has acquired for its author a reputation which 

 will endure so long as anatomical science is 

 cultivated. 



This article is divided into three parts ; the 

 first part, containing a brief account of the 

 general form and structure of the renal organs 

 in the lower animals, as introductory to the 

 second part, which contains an account of the 

 anatomy and physiology of the human kidney, 

 with references to such facts in the minute 

 structure of the kidneys of some of the lower 

 animals as will serve to throw light upon the 

 structure and office of the organ in man. The 

 third part contains an outline of the pathology 

 of the kidney. 



* In explanation of the use of the Latin word 

 REN as the heading of this article, the Editor deems 

 it necessary to state, that the article was undertaken 

 some years ago by a gentleman who failed to com- 

 plete his engagement in time for its publication 

 under the title KIDNEY ; it was found necessary, 

 consequently, to postpone the subject, and to adopt 

 the present title. The article was subsequently 

 committed to other hands, in which it shared a simi- 

 lar fate to that which it experienced at first, and it 

 ultimately fell into the hands of its present able 

 author. ED. 



f Philosophical Transactions, 1842. 



Q 4 



