200 SKELETON. 



The first phalanx is the largest. Its posterior face is semi- 

 cylindrical, the anterior face is flattened, and concave in its 

 length. The two surfaces run into each other by forming a 

 ridge on either side, from which arises the theca of the flexor 

 tendons. The metacarpal extremity is enlarged, and presents 

 a superficial cavity, which receives the end of the metacarpal 

 bone. On either side of this end of the bone is a small tuber 

 for the lateral ligament. The lower extremity is also enlarged 

 and flattened at its sides. Its articular face is extended in 

 front, and presents two condyles, or small heads, for joining 

 the second phalanx. 



The second phalanx is likewise second in size and length. It 

 is semi-cylindrical on its posterior face, flattened on its ante- 

 rior, which is somewhat concave in its length, and the two sur- 

 faces form a ridge, on either side, into which the tendon of the 

 flexor sublimis is inserted, and from which arises the theca of 

 the flexor tendons. Its extremities are slightly enlarged : the 

 articular face of the upper presents two superficial cavities for 

 the condyles of the first phalanx : the articular face of the lower 

 extremity presents a trochlea, with a slight elevation at each 

 side. 



The third phalanx is the smallest of the three, and is very 

 different from the others. Its superior extremity being en- 

 larged, presents an articular face, having two superficial cavities, 

 which adjust themselves to the corresponding face of the last 

 described bone. The inferior extremity is semicircular, thin, 

 and flattened, its margin being very rough, and somewhat ex- 

 panded. The posterior face of the body is convex, and the an- 

 terior flat. 



The phalanges of the middle finger (Impudicus) are larger 

 and longer than the others. The phalanges of the fore finger 

 (Indicator) are next in size, but not in length, as the ring finger 

 is rather longer than it. The phalanges of the ring finger (An- 

 nularis) are next in size, and those of the little finger (Auricula- 

 ris) the smallest and shortest of any. 



The thumb (Pollex) having but two phalanges, the first cor- 

 responds sufficiently in its general form with the first one of 



