ARTICULATIONS 335 



Naviculo-cuneiform Articulation. The three cuneiform 

 bones articulate with the anterior surface of the navicular. 

 They are held in position by dorsal ligaments, which pass from 

 the dorsal surface of the navicular to the dorsal surface of each 

 of the cuneiform bones, and by plantar ligaments, which are 

 similarly disposed. The strength of the plantar ligaments is 

 greater than that of the dorsal ligaments, and they are very 

 largely formed by slips from the tendon of the tibialis posterior. 



The dissector may now divide freely all the dorsal and the most medial of 

 the plantar naviculo-cuneiform ligaments. The navicular bone can then be 

 drawn posteriorly so as to expose the interior of the joint. The knife may 

 also be carried round the lateral side of the lateral calcaneo- navicular 

 ligament. A much better view of this ligament is thus obtained, although 

 this dissection entails the division of the dorsal naviculo-cuboid ligament. 



The convex anterior articular surface of the navicular fits 

 into a transversely concave socket, which is formed for it by 

 the proximal surfaces of the three cuneiform bones, and often 

 by a small facet on the medial surface of the cuboid as 

 well. The articular surface of the navicular is divided by 

 prominent ridges into areas or facets corresponding with the 

 different parts of the socket in which it lies. The synovial 

 membrane, which lines this joint, is prolonged forwards into the 

 intercuneiform joints. 



Naviculo-cuboid and Cubo-cuneiform Articulations. It has 

 been noted that the anterior pillar of the longitudinal arch of 

 the foot consists of a lateral and a medial column. The 

 tarsal portions of these are connected together by the naviculo- 

 cuboid and the cubo-cuneiform articulations. 



It is only occasionally that the navicular touches and 

 articulates directly with the medial surface of the cuboid. 

 When it does so, the facet on the cuboid lies in series 

 with the articular surfaces on the proximal ends of the cunei- 

 form bones, and forms with them the socket for the distal 

 surface of the navicular. The ligaments which bind the 

 navicular to the cuboid are disposed transversely, and 

 consist of (i) a series of short strong interosseous fibres 

 which bind the opposed surfaces together; (2) a dorsal band; 

 and (3) a plantar band. 



The dorsal band has previously been divided in exposing 

 the interior of the naviculo-cuneiform joint and in defining the 

 lateral calcaneo-navicular ligament, but the interosseous and 

 plantar ligaments may be readily displayed. 



