LIGAMENTS OF TARSAL BONES. 645 



flattening of the arch of the foot, so that its head projects against the 

 calcaneo-scaphoid ligament. In this state the interosseous ligament is 

 put on the stretch. 



Fig. 223. 



a. Posterior, 6, external, and c, in- 

 terosseous ligaments between 

 astragalus and os calcis. 



d. Astragalo-scaphoid. 



e. External calcaneo-scaphoid. 



/. Internal, and g, upper calcaneo- 



cuboid ligaments. 

 h. Dorsal scapho-cuboid band. 

 i, k, I. Dorsal external, middle, 



and internal scapho-cuneiform 



longitudinal bands. 

 n. Dorsal transverse bands between 



the cuneiform and cuboid bones. 



VIEW OP THE DORSAL LIGAMENTS OF THE TARSUS. 



When the pressure of the leg is removed the astragalus is carried up 

 and out by the tightened ligaments and muscles, and the arch of the foot 

 is restored. 



ASTRAGALUS WITH THE SCAPHOID BONE. The head of the astragalus 

 is received into the hollow of the scaphoid bone, and is united to it by a 

 dorsal ligament ; but the place of plantar and external lateral ligaments 

 is supplied by strong bands between the os calcis and the scaphoid bone, 

 which will be noticed below. 



The dorsal astragalo-scaphoid ligament (fig. 223, d) is attached to the 

 astragalus close to the articulation, and to the dorsal surface of the sca- 

 phoid bone : its attachments will be better seen when it is cut through. 



Dissection. The external ligament of the articulation may be seen on 

 the dorsum of the foot in the hollow between the os calcis and the scaphoid 

 bone. Supposing the tendon of the tibialis posticus removed, the interior 

 ligament will be defined in the sole of the foot by cutting some fibro-car- 

 tilaginous substance from it. 



The inferior ligament (fig. 225, c) (calcaneo-scaphoid) is attached 

 behind to the fore part of the sustentaculum tali of the os calcis, and in 

 front, to the hollow on the sustentaculum tali of the os calcis, and in front, 

 to the hollow on the under surface of the scaphoid bone. In the upright 

 posture of the body the tendon of the tibialis posticus is beneath it in the 

 sole of the foot ; and on it the head of the astragalus rests. 



The external calcaneo-scaphoid (fig. 223, e) is placed outside the head 

 of the astragalus, and serves as a lateral ligament to the astragalo-sca- 

 phoid articulation ; it is about three-quarters of an inch deep. Behind, 

 it is fixed to the upper part of the os calcis, between the articular surfaces 

 for the cuboid bone and astragalus ; and in front it is inserted into the 

 outer side of the os scaphoides. 



A synovial membrane serves for this articulation, and sends back a pro- 

 longation to the joint between the fore part of the os calcis and the astra- 

 galus. 



Articular surfaces. The head of the astragalus has two articular faces ; 

 a smaller, below, for the os calcis ; and a larger one, elongated transversely 



