90 



BONES OF THE UPPER LIMB. 



sided, and presents a slight curve with the convexity backwards, but 

 near tlic lower extremity it is slender, straight and cylindrical. The 

 cmierior surface is grooved in the upper half, where the flexor profundus 

 muscle takes origin ; and at its lower cud has an obhque line to which 

 the pronator quadratus is attached. Placed near the upper third is a 

 foramen for vessels, directed upwards into the medullary cavity. The 

 internal surface is smooth, and somewhat depressed superiorly on the 

 side of the olecranon, where it gives attachment to the flexor profundus 

 muscle, while inferiorly it is subcutaneous. 1l\\q posterior surface, movo, 

 uneven, looks outwards and backwards ; an oblique ridge descending 

 from behind the small sigmoid cavity, limits superiorly a triangular 

 area, which extends over the outer side of the olecranon and gives 

 attachment to the anconeus muscle ; immediately below the small 

 sigmoid cavity is a short space looking directly outwards, to which 

 the supinator Iwcvis is attached : while the remaining and largest part 

 of this surface is slightly impressed by the extensor muscles. Of the 

 three margins, the anterior and posterior are rounded, and for the most 

 part smooth ; the external is sharp, and gives attachment to the inter- 

 osseous ligament. 



The inferior extremity presents a rounded articular head ; and on the 

 internal aspect of the head a short cylindrical projection, the styloid 

 process, which descends in a line with the inner and posterior surface of 

 the shaft, and gives attachment to the internal lateral ligament of the 

 wrist joint. The head presents two aspects, of which one, flattened 

 and circular in form, looks towards the wrist joint ; whilst the other, 

 narrow and cylindrical, looks outwards, and is received into the semi- 

 lunar cavity in the contiguous border of the radius. The head and the 

 styloid process are separated posteriorly by a groove, which is traversed 

 by the tendon of the extensor carpi ulnaris ; and inferiorly by a de- 

 pression, into which tlie triangular fibro-cartilage which intervenes 

 between the ulna and the carpus is inserted. 



THE CARPUS. 



The carpus is composed of eight short bones, whicn arc disposed in 



Fig. 77. Fig. 77. — Semi-di.vgr.\mmatic Vikw op 



THE Right Carpus anp Part op tub 

 Metacarpal Bones, from before, the 

 Carpal IJoNESBEiNo SLIGHTLY separated 



TO SHOW THE general MOPE OP THEIR 

 connection WITH EACH OTHER. (A. T.) | 



1, scai)hoi(l bone ; 2, semilunar, pre- 

 senting, as often occurs, a small surface of 

 articulation witli the unciform bone ; 'A, 

 cuneiform ; 4, pisiform ; 5, trapezium, the 

 figure is placed upon the ridge, to the in- 

 side of which is the groove for the tendon 

 of flexor carpi radialis ; 0, trapezoid ; 7, os 

 magnum, the figure is placed on the 

 tuberosity ; 8, unciform, the figure is 



placed on the unciform process. The articulation of the os magnum with the fourth 



metacarpal bone is represented somewhat too large. 



two ranges, four in each range. Enumerated from the radial to the 

 ulnar side, the bones which constitute the iirst or superior range are 



