JOINTS OF THE FOOT 439 



metatarso-phalangeal joints, which are condyloid joints, permit 

 also abduction, adduction, and circumduction. At all the 

 joints the movements of extension are produced by the 

 extensors of the toes, but extension of the interphalangeal 

 joints of the lateral four toes is produced also by the action 

 of the lumbrical and interossei muscles, which act by means 

 of their attachments to the extensor expansions. Flexion of 

 the terminal interphalangeal joints of the lateral four is 

 produced by the flexor digitorum longus ; flexion of the first 

 interphalangeal joint by the short flexor of the toes, aided 

 by the long flexor of the toes. In flexion of the metatarso- 

 phalangeal joints the long and short flexors play a part, but 

 they are aided by the lumbrical and interossei muscles, and 

 in the case of the little toe by the flexor digiti quinti brevis. 



Flexion and extension of the interphalangeal joint of the 

 great toe are produced by the long flexor and extensor respec- 

 tively, and flexion and extension of the metatarso-phalangeal 

 joint by the short flexor and extensor, aided by the long flexor 

 and extensor. The dissector should remember that the 

 lumbrical and interossei are flexors of the metatarso-phalan- 

 geal joints and extensors of the interphalangeal joints. 



Abduction and adduction of the toes at the metatarso- 

 phalangeal joints are produced by the interossei and the 

 special abductors and adductors. The movements take place 

 from and towards a line drawn longitudinally along the middle 

 of the second toe. The lateral three toes are adducted by 

 the plantar interossei, the great toe by the oblique and trans- 

 verse adductors. The great toe and the little have each a 

 special abductor muscle. The second toe is alternately 

 abducted and adducted away from or towards its own middle 

 line by the first and second dorsal interosseous muscles. The 

 third toe is abducted by the third, and the fourth toe by the 

 fourth dorsal interosseous muscle. 



