88 PHALANGES. PELVIS. 



dorsal interosseous ; of the index finger, five, the extensor carpi radialis 

 longior, flexor carpi radialis, first and second dorsal interosseous, and 

 first palmar interosseous ; of the middle finger, four, the extensor 

 carpi radialis brevior, adductor pollicis, and second and third dorsal in- 

 terosseous ; of the ring-finger, three, the third and fourth dorsal inter- 

 osseous, 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 conformation 

 they are long bones, divisible into a shaft, and two extremities. 



The shaft is compressed from before backwards, convex on its 

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

 extremity, or base, in the first row is a simple concave articular surface, 

 that in 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 ex- 

 panded into a semilunar crest. 



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

 base. Ossification commences first in the third phalanges, then in the 

 first, and lastly in the second. The period of commencement corre- 

 sponds with that of the metacarpal bones. The epiphyses of the first 

 row appear during the third or fourth year, those of the second row 

 during the fourth or fifth, and of the last during the sixth or seventh. 

 The phalanges are perfected by the twentieth year. 



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 internodii. 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 digitorum. 



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. 



