436 THE INFERIOR EXTREMITY 



cavity. The second metatarsal rests against the second cunei- 

 form, but its base is grasped by the projecting anterior 

 ends of the first and third cuneiform bones, with both of 

 which it articulates, and with both of which it is connected 

 by interosseous ligaments. It is not surprising, therefore, 

 that this metatarsal should possess so little power of inde- 

 pendent movement, and present a difficulty to the surgeon 

 when he is called upon to amputate the anterior part of the 

 foot through the tarso- metatarsal articulation. The third 

 metatarsal rests against the third cuneiform. The synovial 

 layer which lines the joints between the tarsus and the second 

 and third metatarsal bones is continuous with that which is 

 present between the first and second cuneiform bones, and 

 through that with the synovial layer of the cuneo-navicular 

 articulation. The bases of the fourth and fifth metatarsal 

 bones are supported by the cuboid, but that of the fourth, 

 by its medial margin, articulates also with the third cunei- 

 form. The joint formed between the lateral two metatarsal 

 bones and the tarsus has a capsule and a cavity separate from 

 that of the adjacent joints. 



Intermetatarsal Joints. The bases of adjacent metatarsal 

 bones, with the exception of the first, articulate with each 

 other, and are very firmly bound together. 



The ligaments which connect the bases of the four lateral 

 metatarsal bones are dorsal, plantar, and interosseous. They 

 are strong bands which pass between the non-articular por- 

 tions of the basal parts of the bones, and they constitute the 

 chief bonds of union. 



Dissection. To bring the interosseous ligaments into view 

 divide the dorsal ligaments and then forcibly separate the bases 

 of the bones from one another. 



In addition to the ligaments which connect the basal ends 

 of the metatarsal bones, the strong transverse metatarsal liga- 

 ment of the heads of the metatarsal bones unites the distal 

 extremities of the bones together. That ligament has been 

 previously described (p. 399). 



Joint Cavities of the Foot. There are six separate 

 joint cavities in connection with the tarsal, tarso-meta- 

 tarsal, and intermetatarsal articulations, viz. (i) The cavity 

 between the posterior facets of the talus and calcaneus. 

 (2) The calcaneo-cuboid joint cavity. (3) The cavity of the 



