Chap*- 9-3 Bones of the For f -vrtft. i&$ 



long fhape. The internal is more protuberant, and 

 fervesj as well as the former, to give origin to many 

 mufcles. Between thefe two condyls are two lateral 

 protuberances) which) together with a middle cavity, 

 form a kind of pully, on which the motions of the fore- 

 arm are chiefly performed. 



The antibrachium, or fore-arm, eonfifts of two bones, 

 the ulna and the radius. The ulna, which is the longer 

 of the two bones, and is that by which the fore-arm is 

 chiefly connected with the arm, is large above and 

 fmall below, and is of an irregular cylindrical form. 

 At the fuperior extremity of the ulna there are two pro- 

 cefies, a larger one called the olecranon, placed pofte- 

 riorly, and a fmaller, called the coronoid, at the anterior 

 part. At the upper end of the ulna, between thefe 

 procefies, is a cavity divided by a projecting line, and 

 covered with fmooth cartilage, for the reception of the 

 correfponding projections of the os humerh There is 

 another cavity at the fide of the coronoid procefs, co- 

 vered with cartilage, on which the fuperior end of the 

 radius rclls in fome of the motions of the hand. At 

 the lower extremity of the ulna, which is much fmaller 

 than the upper, is a head with a flight excavation, 

 and a fmall procefs called the ftyloid, which forms a 

 projection at the lower end of the fore-arm, on the 

 fame fide with the little finger, not unlike the ankles. 

 The ulna is firmly connected above, by a hinge joint, 

 to the os humeri, laterally to the radius, and flightly 

 below to the carpus, and its articulations 'are every 

 where firmly fecured with ligaments. 



The radius is a bone of nearly the fame form, fize, 

 and appearance, with the ulna. As the larger dnd of 

 the ulna is firmly connected with the os humeri, fo that 

 of the radius is connected to the carpus. On the con- 

 trary, the connexions of the ulna with the carpus, and 



VOL. III. K of 



