218 



OSTEOLOGY. 



OS CAPITATUM 

 LESSER MULTANGULAR 



NAVICULAR 



ABDUCTOR POLLICIS BREVIS 

 GREATER MULTANGULAR 

 OPPONENS POLLICIS 

 ABDUCTOR POLLICIS LONGUS 



FLEXOR CARPI RADIALIS 



M.I. 



ADDUCTOR/ OBLIQUE HEAD 

 POLLICIS 1 TRANSVERSE HEAD 



Os LUNATUM 



OS HAMATUM 



OS TR1QUETRUM 

 FLEXOR CARPI ULNARIS 

 PISIFORM 

 ABDUCTOR DIGITI QUINTI 



FLEXOR DIGITI QUINTI 



BREVIS 



FLEXOR CARPI ULNARIS 



OPPONENS DIGITI 

 QUINTI 



VOLAR 



INTEROSSEI 



FIG. 210. VOLAR ASPECT OP BONES OF THE RIGHT CARPUS 

 AND METACARPUS WITH MUSCULAR ATTACHMENTS MAPPED OUT. 



os hamatum (O.T. unciform). Irregularly six-sided, each of these bones possesses 

 non-articular volar and dorsal surfaces. In addition, the marginal bones are non- 

 articular along their ulnar and radial aspects according as they form the medial or 

 lateral members of the series. 



Os Naviculare(O.T. Scaphoid). Thenavicularis the largest and the most lateral 



bone of the first row. 

 Its volar surface, 

 rough for the attach- 

 ment of ligaments, is 

 irregularly triangu- 

 lar. The distal 

 angle on the lateral 

 side forms a projec- 

 tion called the tuber- 

 osity; this can be 

 felt at the base of 

 the root of the thumb. 

 Its proximal surface 

 is convex from side to side and 

 before backwards for articula- 

 tion with the radius. This area 

 extends considerably over the 

 dorsal surface of the bone. 

 Its distal surface is convex 

 from before backwards, and ex- 

 tends on to the dorsal aspect of 

 the bone, slightly convex from 

 side to side ; it is divisible into two areas, the lateral for articulation with the greater 

 multangular, the medial for the lesser multangular- The lateral surface is narrow 

 and rounded and forms a non-articular border, which extends from the radial articular 

 surface proximally to the tuberosity distally. The medial surface is hollowed out in 

 front for articulation with the head of the capitate bone. Proximal to this it displays 

 a small semilunar- 

 shaped facet for the os 

 lunatum. The dorsal 

 non - articular surface 

 lies between the lateral 

 articular surface proxi- 

 mally and the surface for EXTENSOR CARPI 

 the greater and lesser 

 multangular bones dis- 

 tally. It is obliquely 

 grooved for the attach- 

 ment of the dorsal liga- 

 ments of the wrist. The 

 navicular articulates 

 with five bones the 

 radius, the os lunatum, 

 the capitate, the lesser 

 multangular, and the 

 greater multangular. 



Os Lunatum (O.T. 

 Semilunar Bone). So 

 called from its deeply 

 excavated form, the os lunatum lies between the navicular on the lateral side and 

 the os triquetrum on the medial. Its volar surface, of rhombic form and consider- 

 able size, is rough for the attachment of ligaments ; its proximal surface, convex from 

 side to side and from before backwards, articulates with the radius and in part 

 with the distal surface of the articular disc of the wrist. Its distal aspect, deeply 



OS TRIQUETRUM 

 PISIFORM 



OS HAMATUM 



OS LUNATUM 



OS CAPITATUM 



NAVICULAR 



EXTENSOR CARPI RADIALIS BREVIS 

 LKSSER MULTANGULAR 

 GREATER MULTANGULAR 

 EXTENSOR CARPI RADIALIS LONGUS 

 ABDUCTOR POLLICIS LONGUS 



FIG. 211. DORSAL ASPECT OF BONES OF THE RIGHT CARPUS AND 

 METACARPUS WITH MUSCULAR ATTACHMENTS MAPPED OUT. 



