222 



OSTEOLOGY. 



medial aspect of its volar surface. 



Capitate bone 



II. Metacarpal 



Navicular 



Greater 

 multangular 



To this is attached the transverse carpal 

 ligament as well as some of the 

 fibres of origin of the short muscles 

 of the little finger. The medial 

 side of the hamulus is sometimes 

 grooved by the deep branch of the 

 ulnar nerve. ( Anderson, W.,"Proc. 

 Anat. Soc." Journ. Anat. and 

 Physiol. vol. xxviiip. 11.) The volar 

 surface, rough for ligaments, is 

 somewhat triangular in shape 

 Proximally and towards the medial 

 side there is an elongated articular 

 surface for the os triquetrum, 

 convex proximally and concave 

 distally. The lateral aspect of the 

 bone is provided with a plane elon- 

 gated facet, occasionally divided 

 into two for articulation with the 

 capitate bone (see above). Where 



F,G. 218.-THB EIGHT LESSKR MULTANGULAR BONE. the P"! and lateral surfaces 



. meet, the angle is blunt, and has 



NOTE. The bone is represented in the centre of the figure in * 



the position which it occupies in the right hand viewed a narrow tacet which articulates 



from the volar aspect. The views on either side, and with the OS lunatum. Distally 

 above and below, represent respectively the corresponding ^ere are two articular facets 

 surfaces of the bone turned towards the reader. L i i ^ 



separated by a ridge; these are 



slightly concave from before backwards, and are for articulation, the lateral with 

 the fourth, and the medial 

 with the fifth metacarpal 

 bone. The dorsal surface, 

 more or less triangular in 

 shape, is rough for liga- 

 ments. 



The os hamatum articu- 

 lates with five bones viz., 

 the capitate, os lunatum, os 

 triquetrum, and the fourth 

 and fifth metacarpals. 



IV. Metacarpa 



I. Metacarpal 



III. Metacarpal 



Os lunatum 



The Carpus as a ~ 

 Whole. 



When the carpal bones 

 are articulated together 

 they form a bony mass, the 

 dorsal surface of which is 

 convex from side to side. 

 Anteriorly they present a 

 grooved appearance, con- 

 cave from side to side. 

 This arrangement is further 

 emphasised by the forward 

 projection, onthe medial side, 

 of the pisiform and hamulus 

 of the os hamatum, whilst 

 laterally the tuberosity of 

 the navicular and the ridge 

 of the greater multangular help to deepen the furrow 'by their elevation. 



Os lunatum 



Navicular 



Os hamatum- 



FIG. 219. THE RIGHT CAPITATE BONE. 



NOTE. The bone is represented in the centre of the figure in the 

 position which it occupies in the right hand viewed from the 

 volar aspect. The views on either side, and above and below, 

 represent respectively the corresponding surfaces of the bone turned 

 towards the reader. 



To these 



