THE LOWER LIMB 



589 



The dorsal ligaments are short transverse bands, three in number, 

 which pass between the dorsal aspects of the bases of the second 

 and third, third and fourth, and fourth and fifth metatarsals. 



The plantar ligaments are disposed in a similar manner to the 

 preceding on the plantar aspects of the bases of the four outer 

 metatarsals. 



The interosseous ligaments, which are three in number, are 

 deeply placed and of considerable strength. They constitute a 

 very firm bond of union between the contiguous sides of the bases 

 of the outer four metatarsals, to the non-articular parts of which 

 they are attached. 



Synovial Membrane. — In the case of the joints between the 

 bases of the second and third and third and fourth metatarsals' 

 the synovial membrane is a forward extension of that of the middle 

 tarso-metatarsal joint, which sends forward two prolongations. 



, Interosseous Ligament 



Fig. 272. — The Synovial Cavities of the Tarsal and 

 Tarso-metatarsal Joints. 



In the case of the joint between the bases of the fourth and fifth 

 metatarsals the synovial membrane is a forward prolongation of 

 that of the cubo-metatarsal joint. As regards the contiguous 

 sides of the bases of the first and second metatarsals, if they should 

 articulate, a special synovial bursa is usually provided which some- 

 times communicates with the sjniovial membrane of the internal 

 tarso-metatarsal joint. 



The arterial supply and nerv^e-supply are derived from the same 

 sources as in the case of the tarso-metatarsal joints. 



Movements. — These are of a purely gliding or to-and-fro nature, so as to 

 increase or diminish the span of the transverse arch of the foot. 



The heads of all the metatarsal bones are cormected by the 

 transverse metatarsal (deep transverse) ligament, which extends 

 across their plantar aspects. Its fibres are attached to the fibrous 

 plates on the plantar surfaces of the metatarso-phalangeal joints, 



