TARSAL ARTICULATIONS. 



155 



Dorsal, 



Plantar, 



Interosseous. 



The dorsal ligaments are small fasciculi of parallel fibres, which pass 

 from each bone to all the neighbouring bones with which it articulates. 

 The only dorsal ligaments deserving of particular mention are, the ex- 

 ternal and posterior calcaneo-astragaloid, which, with the interosseous 

 ligament, complete the articulation of the astragalus with the os calcis ; 

 the superior and internal calcaneo-cuboid ligaments ; and the superior 

 astragalo-scapJioid ligament. The internal calcaneo-cuboid and the 

 superior calcaneo-scaphoid ligament, which are closely united poste- 

 riorly in the deep groove which intervenes between the astragalus and 

 os calcis, separate anteriorly to reach their respective bones ; they form 

 the principal bond of connection between the first and second range of 

 the bones of the foot It is the division of this portion of these liga- 

 ments that demands the especial attention of the surgeon in performing 

 Chopart's operation. 



The plantar ligaments have the same disposition on the plantar 

 surface of the foot ; three of them, however, are of a large size and 

 have especial names, viz. the 



Calcaneo-scaphoid, Fi S- 75.* 



Long calcaneo-cuboid, 

 Short calcaneo-cuboid. 



The inferior calcaneo-scapkoid ligament is a 

 broad and fibro-cartilaginous band of ligament, 

 which passes forwards from the anterior, and 

 inner border of the os calcis to the edge of the 

 scaphoid bone. In addition to connecting the 

 os calcis and scaphoid, it supports the astra- 

 galus, and forms part of the cavity in which the 

 rounded head of the latter bone is received. It 

 is lined upon its upper surface by the synovial 

 membrane of the astragalo-scaphoid articulation. 



The firm connection of the os calcis with the 

 scaphoid bone, and the feebleness of the astra- 

 galo-scaphoid articulation are conditions favor- 

 able to the occasional dislocation of the head 

 of the astragalus. 



The long calcaneo-cuboid^ or ligamentum longum plants, is a long 

 band of ligamentous fibres, which proceeds from the under surface of 

 the os calcis to the rough surface on the under part of the cuboid bone, 



* A posterior view of the ankle joint. 1. The lower part of the inter- 

 osseous membrane. 2. The posterior inferior ligament connecting the tibia 

 and fibula. 3. The transverse ligament. 4. The internal lateral ligament. 

 5. The posterior fasciculus of the external lateral ligament. 6. The middle 

 fasciculus of the external lateral ligament. / The synovial membrane of the 

 ankle joint. 8. The os calcis. 



