154 COUES ON THE OSTEOLOGY 



The third or "ulnar finger" is a single short, slight phalanx, about half an inch long. 

 It proceeds from the extremity of the ulnar metacarpal, with which it is articulated, but 

 is so firmly bound by ligaments to the under edge of the first phalanx of the larger 

 radial finger that it enjoys little or no motion. 



The middle or "radial finger" forms the proper continuation of the hand. It consists 

 of three phalanges. The first is of considerable size, being one and a quarter inches long, 

 its radial side thick and flat, and separated by quite distinct borders from the thin lamelloid 

 expansion on its ulnar aspect. Its proximal end articulates with the distal extremity of 

 the metacarpus by a slightly depressed and irregular surface. The second phalanx is much 

 smaller, though of about the same length as the preceding, from which it differs chiefly in 

 not having the compressed lamella of bone proceeding from its ulnar aspect. It articulates 

 with the preceding by an enlarged head. The third phalanx is merely a very small, insig- 

 nificant, acutely pointed spicula of bone, scarcely a third of an inch long. 



Ossa innomiaata. The innominate bones are remarkable for their great length antero- 

 posteriorly, as well as for their extreme narrowness and the straightness of their longitu- 

 dinal axis, which latter is scarcely more curved than is that of the sacrum itself. They 

 measure, from the tip of the ilium to the tuberosity of the ischium, six and a half inches; 

 and they extend from the interspace between the sixth and seventh ribs to that between 

 the second and third coccygeal vertebrae. Throughout this extent, they are very closely 

 apposed to, and lie parallel with, the spine ; and they are completely ancliylosed with 

 it, except for about half an inch at each extremity. Besides the want of antero-pos- 

 terior curvature, the bones — leaving out of consideration the rami of the pubes, which 

 are curved towards each other on the median line — have little or no lateral convexity. 

 They converge towards each other on the spine, at an angle of about 50°, forming a 

 greatly elongated, very narrow pelvis ; which, by the flattened shape of the ischia is quite 

 deep and transversely triangular posteriorly, but which, more anteriorly, by the termina- 

 tion of the pubes at the acetabula, and the outward expansion of the ilia, becomes so 

 shallow as quite to lose its characteristics as a "cavity." On the median line, the ilia, as 

 usual in the class, do not meet, but are throughout separated by the ancliylosed spinous 

 processes of the sacral vertebra?. The approximation of the two cristas ilii is greatest just 

 posterior to the ischiadic foramen ; both anterior and posterior to this point the bones 

 slightly recede from the median line of the vertebra?, the amount of divergence gradually 

 increasing, until the tips of the ilia are three fourths of an inch, and the tubera ischii one 

 half an inch, from the median line. 



Ilium. This portion of the os innominatum is, anteriorly to the acetabulum, a very thin, 

 narrow, osseous prolongation, extending forwards and a little outwards as far as the seventh 

 rib. It is externally concave antero-posteriorly, and also laterally very slightly so. It is 

 completely ancliylosed, to within less than one half an inch of the tip, with the trans- 

 verse processes of the sacral vertebra? over which it is imposed. It has no connection, 

 however, with the last ribs, though these pass out so close beneath it that they almost 

 touch its internal surface. Towards the acetabulum the bone spreads out as a stout curve, 

 which meets a similar projection from the ischio-pubic bone, and then completes the circle 

 of the acetabulum. Just above the ring, the acetabulum proper, the bone becomes very 

 thick and strong, and is elevated into a projection which overhangs as it were the cotyloid 

 cavity. This eminence is suboval in shape ; and bears upon its summit a flat, smooth, 

 articular facet, continuous with the articular surface of the acetabulum proper, to which is 



