I2r. 



Tin: SKELETOX 



THE RADIUS 



The radius is shorter than the ulna and lies parallel with it. The upper end 

 or head, is surmounted hx a c-ireular dise, of which the superior surface is deprc'ssed 

 for the reception of the capitcllum of the humerus, especially m Hexion ot the tore- 

 •irm The mart,nn of the head is also articular; it is deeper on the uhiar aspect, 

 where it is receiViHl i)v the lesser sigmoid cavity of the uhia; the rest of the circum- 



I'u;. i:51.-AKTurL.\u Facets on the Lower End of Left EADirs and Ulxa. 



Posterior 



RADIUS ULNA 



FOR SCAPHOID 

 FOR SEMILUNAR — ^^ 



STVLOlO PROCESS OF ULNA 



HEAD OF ULNA: IT ARTICULATES WITH 

 THE INTERARTICULAR FIBRO-CARTiLAGE 

 OF THE WRIST-JOINT 



ference is embraced by the orbicular ligament. Below the cartilage-covered surface 

 of the bone there is a constricted portion, or neck, which is in relation by its outer 

 side with the supinator breviii. 



Bi'neath the n(>ck, on the antero-internal aspect of the bone, there is an oval 

 eminence, the bicipital tuberosity, divided longitudinally into a rough posterior 

 portion for the bicejis tendon, and a smooth anterior surface in relation with the 

 bursa which is situated between the tendon and the tuberosity. 



The radius has three borders and three surfaces. Of the three borders, the 



Fig. 132. — Posteriok View of the Lower End of the Radius and Ulna. 



Insertion of aupinator loneus 



Ext. ossis metacarpi pollicia and 

 Ext. primi intcrnocfii pollicis 

 ExtenBOr carpi radialia 

 longior and brevior 

 TUBERCLE FOR POSTERIOR ANNULAR 



LIGAMENT 



Extensor secundi internodii 



polliciu 



STYLOID PROCESS 



Ext. commuDis dlgltorum and 



extensor indicis 

 Extensor minimi digit! lies in 



the groove between the radius 



and ulna 

 Extensor carpi ulaaris 



STYLOID PROCESS 



interosseous is the best marked. Commencing at tiie posterior edge of the 

 bici])ital tuberosity, it extends as a sharp ridge until it ai)proaches the distal ex- 

 tremity of thebone; it then divides to l)ecome continuous with the anterior and 

 l)o.<terior margins of tlie sigmoid cavity. It aflPords attachment to the interosseous 

 membrane. The anterior border starts from the bicipital tul)erosity, crosses 

 ol)li(|Uely to 1]i(> outer side of tlie l)one, and descends to the anterior border of the 

 styloid process. The upi^er third of this border is called the oblique line, and 

 limits the. insertion of tlie bitpinator hrevis and the origui of ihefiexor longus polUcis, 



