44 



THE BOXES AND JOINTS. 



ulnar portion of the bone forms a cajntulnm. The structure of 

 the inferior extremity is that of ejîiphyses in general, except that 

 there are two medullary cavities in a common sheath of calcified 

 cartilag-e; the anterior head consists of cancellous tissue, with a 

 covering- of calcified cartilag-e. 



I'ig- 39- 



" ,t 





Bones of the forearm and hand of Ihina 

 I'sculcnta, right side, dorsum, twice 

 nat. size. 



a Os antibrachii. 



he Os capitato-haniatum. 



I Os hinatum. 



m Ossa metacarpi. 



n Os naviciilare. 



]) Os pyramidale. 



r Radial portion of the radiu-ulnar. 



t Os multantfiilnm majus or trapeziiim. 



t' Os multangulum minus or trapezoides. 



« Ulnar portion of the radio-ulnav. J 



/— V First to fifth finders, the-fiftli only 

 of OS metacarpi, the second'and third 

 of two, fonrth and fifth of three 

 phalcinges. 



3. Bones of the hand (Fig. 39). 



Dugès, PI. VIII, Fig's. 37, 38. 39, 40, 4]. 



42, 43, .52- 



a. Bones of the wrist, o.'^m carpi. 

 These are arranged in two rows, proxi- 

 mal and distal. The proximal or an- 

 terior row has three bones, viz. : — 



1 . Os liinahim, the middle bone (Fig. 

 39 /), Dug-es, n. 38, articulates with the 

 radial part of the articular surface of 

 the radio-ulnar by a concave surface; 

 with the larg-e bone of the second row 

 [he) it articulates by means of a rounded 

 head; and with the two other bones 

 of this row, os navicnlnre [n) and pyra- 

 midale [p), with the former by a saddle- 

 shaped surface, with the latter chiefly 

 by ligament. The bone is irregularly 

 cuboid ; the dorsal and palmar surfaces 

 are non-articular. With Dugès I regard 

 this bone as os lunatum,', Mertens^ re- 

 gards it as OS navicHlare. 



2. Os pyramidah (Fig. 39 7>), Dugès, 

 n. 37, articulates with the ulnar part 

 of the posterior articular extremity of 

 the radio-ulnar. Anteriorly the bone 

 has a facet which receives the capitn- 

 lum idnae, and alongside this a small 

 flat surface which articulates with the 

 radiiTs. Posteriorly, opposite to the 

 second row, it presents a long raised 

 articular surface, extending from the 

 dorsum to the palmar surface ; and on 



Mer tens. I. c. 



