THE rOKE-LIMB. 45 



the palmar aspect of the bone is a ridge running' from before back- 

 wards. Mertens names this bone os limatum. 



3. Os naviculare (Fig. 39 n), Duges^ n. 39. The third bone 

 of the first row does not articulate with the bones of the forearm. 

 It is connected with the os lunatum by a saddle-shaped surface, pos- 

 teriorly with the OS capltatum by means of a concave surface. On 

 the inner surface is a small concave articular facet for the os midt- 

 avgulum minus or trapezoides (Fig. 39 f). The convex palmar 

 surface of the bone articulates with the os multangulam viajus (/) ; the 

 radial side is non-articular, and with the os lunatvvi forms a ridge 

 directed forwards. Mertens names this bone os triqneinnn. It is 

 evident^ however^ that if the arrangement in man obtains as a 

 standard^ the nomenclature of Dugcs, which I have here used, is 

 correct; but the os naviculare is no longer in contact with the 

 articular surface of the os uniihrachii. 



The second or distal row also consists of three bones : — ' 



4. Os capitato-hamatum (Fig. 39 he), Duges, n. 4c, 41, 42, 

 corresponds with the os capitafum and hamaium ^, which are here 

 fused together. It is the largest bone, and articulates with all three 

 bones of the first row ; it is crescentic, with the concavity directed 

 posteriorly, and on the convex surface has three facets for the three 

 outer ossa metacarpÀ. 



5. Os mnHangulniii minus, s. trapezoides (Fig-. 39 t'), Dugès, 

 n. 43, is a small bone h'ing next to the foregoing; it articulates 

 with the OS vielacarpi II, and anteriorly with the os naviculare. 

 Duges considers it to be the os trapezium . 



6. Os multanguhun viajus, s. trapezium (Fig. 39 t), is a small 

 bone, which is placed on the convex palmar auricular side of the 

 OS naviculare. Duges regards this bone as os metacarpi pjolUcis 

 (Duges, n. 44), Mertens as muJtangulum minus. It appears to me 

 that the interpretation here given is justified, because it articulates 

 with the rudiment of the thumb, and as it possesses no resemblance 

 to a long bone it cannot be regarded as an os metacarpi. 



Structure of the carpal bones. All the cardial bones consist 

 of calcified cartilage, though variations due to age occur in the 

 amount of the deposit. 



Wrist joint. As stated above, the os lunatum and ospp-amidale are 

 articulated with the forearm. In addition to the capsules uniting 

 the parts, there are strengthening ligaments, two of which require 

 special mention. One of these arises from the palmar surface of 



' Duges thinks that os tiujxzokles is also included. 



