84 METACARPUS PHALANGES. 



and third dorsal interosseous ; of the ring-finger, three the third 

 and fourth dorsal interosseous, and second palmar ; and of the little 

 finger, four extensor carpi ulnaris, adductor minimi digiti, fourth 

 dorsal and third palmar interosseous. 



PHALANGES. The phalanges are the bones of the fingers ; they 

 are named from their arrangement in rows, and are fourteen in 

 number, three to each finger, and two to the thumb. In confor- 

 mation they are long bones, divisible into a shaft, and two extre- 

 mities. 



The shaft is compressed from before backwards, convex on its 

 posterior surface, and flat with raised edges in front. The meta- 

 carpal extremity of the first row is a simple concave articular surface 

 of the other two rows a double concavity, separated by a slight 

 ridge. The digital extremities of the first and second row present 

 a pulley-like surface, concave in the middle, and convex on each 

 side. The ungual extremity of the last phalanx is broad, rough 

 and expanded into a semilunar crest. 



Developement. By two centres ; one for the shaft, and one for 

 the metacarpal extremity. 



Articulations. The first row, with the metacarpal bones and 

 second row of phalanges ; the second row, with the first and third ; 

 and the third, with the second row. 



Attachment of Muscles. To the base of the first phalanx of the 

 thumb four muscles abductor pollicis, flexor brevis pollicis, 

 adductor pollicis, and extensor primi internodii ; and to the second 

 phalanx, two the flexor longus pollicis, and extensor secundi in- 

 ternodii. To the first phalanx of the second, third, and fourth 

 fingers, one dorsal and one palmar interosseous, and to the first 

 phalanx of the little finger, the abductor minimi digiti, flexor brevis 

 minimi digiti, and one palmar interosseous. To the second phalanges 

 the flexor sublimis and extensor communis digitorum ; and to the 

 last phalanges the flexor profundus and extensor communis digi- 

 torum. 



PELVIS AND LOWER EXTREMITY. 



The bones of the pelvis are the two ossa innominata, the sacrum, 

 and the coccyx ; and of the lower extremity, the femur, patella, tibia 

 and fibula, tarsus, metatarsus, and phalanges. 



Os INNOMINATUM. The os innominatum is an irregular flat bone, 

 consisting in the young subject of three parts, which meet at the 

 acetabulum. Hence it is usually described in the adult as divisible 

 into three portions, ilium, ischium, and pubis. The ilium is the 

 superior broad and expanded portion which forms the prominence 

 of the hip, and articulates with the sacrum. The ischium is the 

 inferior and strong part of the bone on which we sit. The pubis is 

 that portion which forms the front of the pelvis, and gives support 

 to the external organs of generation. 



The ilium may be described as divisible into an internal and ex- 

 ternal surface, a crest, and an anterior and posterior border. 



