THE LOWER LIMB $87 



bases of the second and third metatarsals, having the shps of the 

 tendon of the tibiahs posticus behind it ; a second passes between 

 the middle cuneiform and the base of the second metatarsal ; and 

 a third passes between the external cuneiform and the base of the 

 third metatarsal, the latter two also having the slips of the tendon 

 of the tibialis posticus behind them. 



The interosseous ligaments are three in number — internal, middle, 

 and external. 



The internal interosseous ligament* extends from the anterior 

 and upper part of the outer surface of the internal cuneiform to 

 the inner surface of the base of the second metatarsal. In each 

 case it is attached below and in front of the articular facet, and 

 it separates the internal from the middle tarso-metatarsal joint. It 

 is a very strong ligament, and offers considerable resistance to the 

 knife in the performance of Lisfranc's operation. The middle inter- 

 osseous ligament extends from the anterior part of the inner surface 

 of the external cuneiform, between the two semi-oval facets, to the 

 groove on the outer surface of the base of the second metatarsal 

 which separates the two facets. The external interosseous ligament 

 extends from the anterior part of the outer surface of the external 

 cuneiform, below the inconstant antero-superior facet, to the outer 

 side of the base of the third metatarsal below the facet. It is also 

 attached to the inner side of the base of the fourth metatarsal, 

 and it ranks as the interosseous ligament of the cubo-meta tarsal 

 joint. 



The synovial membrane of the middle tarso-metatarsal joint is 

 usually continuous with that of the naviculo-cuneiform joint, the 

 continuity taking place between the internal and middle cuneiform 

 bones. Sometimes, however, they are quite distinct from each other. 

 It sends prolongations forward between the bases of the second and 

 third and third and fourth metatarsals. 



III. External Tarso-metatarsal or Cubo-metatarsal Joint. — ^The 

 bones which enter into this joint are the cuboid and the fourth and 

 fifth metatarsals. The ligaments are dorsal, plantar, and inter- 

 osseous. 



The dorsal ligament passes from the dorsal surface of the cuboid 

 to the dorsal surfaces of the bases of the fourth and fifth metatarsals. 



The plantar ligament extends between the plantar surface of the 

 cuboid in front of the peroneal groove and the plantar aspects of 

 the bases of the fourth and fifth metatarsals. It is closely asso- 

 ciated with the forward expansion of the long plantar Ugament and 

 with one of the sMps of the tendon of the tibialis posticus. 



The interosseous ligament is the same as the external interosseous 

 ligament of the middle tarso-metatarsal joint. 



The dorsal, plantar, and interosseous ligaments construct a 

 capsule round the cubo-metatarsal joint. 



The synovial membrane is peculiar to this joint, and sends a 

 prolongation between the bases of the fourth and fifth metatarsals. 



Arterial Supply.— The tarso-metartarsal joints derive their arterial 

 * Lisfranc's ligament. 



