72 



ANATOMY FOR NURSES 



[Chap. V 



Olcrranoa 



Coronoid 



Radiu 



tliat it ends in two condyles by means of which it articulates with 



the radius and ulna. 

 Ulna, or elbow bone. — It is placed at the inner side (little 



finger side) of the forearm, ])arallel with the radius. Its upper 



extremity presents for examina- 

 tion two large curved processes 

 and two concave cavities ; the 

 larger process forms the head 

 of the elbow, and is called the 

 olecranon process. The smaller 

 process on the front surface is 

 termed the coronoid, and the 

 trochlea of the humerus fits into 

 the cavity — the great sigmoid 

 cavity — between these two pro- 

 cesses. The lesser sigmoid cavity 

 is on the outer side of the coro- 

 noid, and receives the head of the 

 radius. The lower extremity of 

 the ulna is of small size and ends 

 in two prominences ; the outer 

 one, called the head, articulates 

 with the radius, the inner one, 

 named the styloid process, serves 

 for the attachment of ligaments 

 from the wrist ; but the ulna is 

 excluded from the wrist bv a 



Fig. 51. — The Bo.nes of the Right • e n\ -i 



FoRE.\RM. Anterior view. (Morrow.) piCCe 01 hbro-cartliage. 



Radius. — It is situated on the 

 outer side of the forearm. The upper end is small and rounded, 

 with a shallow depression on its upper surface for articulation 

 with the humerus, and a prominent ridge about it, like the head of 

 a nail, by means of which it rotates within the lesser sigmoid cavity 

 of the ulna. The lower end of the radius is large, and forms the 

 chief part of the wrist. 



Carpus, or wrist. — The wrist joint is composed of eight small 

 bones (ossa carpi) united by ligaments ; they are arranged in two 

 rows, and are closely welded together, yet by the arrangement 

 of their ligaments allow of a certain amount of motion. They 



