PHALANGES. 107 



transversus pedis ; to the fifth, one dorsal and one plantar interrosseous 

 peroneus brevis, peroneus tertius, abductor minimi digiti, flexor brevis 

 minimi digiti, and transversus pedis. 



PHALANGES. There are two phalanges in the great toe, and three 

 in the other toes, as in the hand. They are long bones, divisible into 

 a central portion and extremities. 



The phalanges of the first row are convex above, concave upon 

 the under surface, and compressed from side to side. The posterior 

 extremity has a single concave articular surface, for the head of the 

 metatarsal bone ; and the anterior extremity, a pulley-like surface, for 

 the second phalanx. 



The second phalanges are short and diminutive, but somewhat 

 broader than those of the first row. 



The third., or ungual pJialanges, including the second phalanx of the 

 great toe, are flattened from above downwards, spread out laterally 

 at the base, to articulate with the second row, and at the opposite ex- 

 tremity, to support the nail and the rounded extremity of the toe. 



Development. By two centres ; one for the body and one for the 

 metacarpal extremity. Ossification commences in these bones after 

 that in the metatarsus, appearing first in the last phalanges, then in 

 the first, and last of all in the middle row. The bones are completed 

 at eighteen. 



Articulations. The first row with the metatarsal bones and second 

 phalanges ; the second, of the great toe with the first phalanx, and of 

 the other toes with the first and third phalanges ; and the third, with 

 the second row. 



A ttachment of Muscles. To twenty-three ; to the first phalanges ; 

 great toe, the innermost tendon of the extensor brevis digitorum, ab- 

 ductor pollicis, adductor pollicis, flexor brevis pollicis, and transversus 

 pedis ; second toe, first dorsal and first palmar interosseous and lum- 

 bricalis ; third toe, second dorsal and second palmar interrosseous and 

 lumbricalis ; fourth toe, third dorsal and third palmar interrosseous and 

 lumbricalis ; fifth toe, fourth dorsal interosseous, abductor minimi 

 digiti, flexor brevis minimi digiti and lumbricalis. Second phalanges ; 

 great toe, extensor longus pollicis, and flexor longus pollicis ; other toes, 

 one slip of the common tendon of the extensor longus and extensor 

 brevis digitorum, and flexor brevis digitorum. Third phalanges; 

 two slips of the common tendon of the extensor longus and extensor 

 brevis digitorum, and the flexor longus digitorum. 



SESAMOID BONES. These are small osseous masses, developed in 

 those tendons which exert a certain degree of force upon the surface 

 over which they glide, or where, by continued pressure and friction, 

 the tendon would become a source of irritation to neighbouring parts, 

 as to joints. The best example of a sesamoid bone is the patella, de- 

 veloped in the common tendon of the quadriceps extensor, and resting 

 upon the front of the knee-joint. Besides the patella, there are four 



