120 



THE BONES. 



groove is 8in<rle, and looks outwards. The inferior articular surface resembles that of animals, 

 except that the condyle is iiioie distinct. 



C. FoKEAKSi (Fig. 80). — The two bones of the forearm, as we have already seen, only articu- 

 late by their extremities; they are separated from one another in their middle part. The 

 Buperior extremity of the radius corresponds with the condyle of the humerus ; that of the uhia 

 articulates with the humeral trochlea. The coronoid process belongs to the ulna. At the 

 lower extremity of the forearm, it is remarked : 1. That the radius corresponds with the greater 

 portion of the citrpus, while the ulna only articulates with the pyramidalis. 2. Tliat the radio- 

 3arpal articulation is protected outwardly and inwardly by two small osseous prolongations — 

 the styloid processes of the ulna and radius. 



D. Hand. — 1. Carpus (Fig. 81). — The carpus of Man is composed of eight bones — four in 

 each row. The three first of the upper row articulate with the radius ; tiie fourth responds to 



Fig. 79. 



Fig. 80. 



l/<r 



RIGHT HUMAN HUMERUS (ANTERIOR 

 SURFACE). 



1, Shaft; 2, head; 3, neck; 4, greater tu- 

 berosity ; 5, lesser tubero^ity ; 6, bici- 

 pital groove ; 7, interior bicipital groove ; 

 8, posterior bicij)ital ridge ; 9, rough sur- 

 face for insertion of deltoid; 10, nutrient 

 foramen; 11, eminentia capitata ; 12, 

 trochlea; 13, e.xternal condyle; 14, in- 

 ternal condvle ; 15, external condyloid 

 ridge ; 16, internal condyloid ridge ; 17, 

 fossa for the coronoid process of ulna. 



HUMAN ARM-BONES (FRONT VIEW). 



1, Shaft of ulna; 2, greater sigmoid notch 5 

 3, lesser sigmoid notch ; 4, olecranon 

 process ; 5, coronoid process ; 6, nutrient 

 foramen ; 7, ridges for insertion of in- 

 terosseous membrane ; 8, capitalum ulnse ; 

 9, stvloid process ; 10, shaft of radius ; 

 11, its head ; 12, its neck ; 1'% its tube- 

 rosity ; 14, oblique line; 15, lower end 

 of bone; 16, styloid process. 



the ulna. In the bones of the lower row, the trapezium responds to the metacarpal of the thumb 

 and that of the index; the trapezoides to the latter only, the os magnum an 1 unciform to the 

 metacarpals of the medius, annularis, and little finger. The pisiform bone and the cuneiform 

 process of the unciform convert the posterior face of the carpus into a channel. 



2. Metacarpus (Fig. 81).— The five metacarpals of Man are parallel to each other; they 

 articulate by their superior extremities with the bones of the carpus, and by iheir inferior ex- 

 tremities with the phalanges. They are all concave in their middle portion, and thickened at 

 their ends. The metacarpal of the thumb is the shortest and strongest. The others diminieb 

 in volume from the fourth to the first. 



