ASTICVLATIONS OF TSE POSTETlTOn LIMPS. 169 



covers the external and deep ligament, the short band which constitutes the 

 external calcaneo-astragaloid ligament, the insertion of one of the branches 

 of the flexor of the metatarsus, and the small cuboido-cunean (cuneiform) 

 ligament. 



The external deep ligament (Figs. 93 ; 94, 1), much shorter than the 

 preceding, is attached, superiorly, to the anterior part 

 of the external tuberosity of the tibia, and is directed ^'S' ^^' 



obliquely backwards and downwards, to be fixed by 

 two fasciculi at the external side of the astragalus 

 and calcis. This ligament, covered by the preceding, 

 which crosses it like an X, is lined on its inner face 

 by the synovial membrane of the articulation. 



b. Internal lateral ligaments. — These are also three 

 funicular bands superposed on one another, and are 

 consequently designated as superficial, middle, and 

 deep. 



The internal superficial ligament (Fig. 93, 6), the 

 strongest and longest of the three, proceeds from 

 the internal and inferior tuberosity of the tibia, 

 diminishing as it descends on the inner side of the 

 tarsus. It is fixed, in mixing with the astragalo- 

 metatarsal ligament and with the posterior tarso- 

 metatarsal ligamentous arrangement, to the tuberosity 

 of the astragalus, the scaphoid, the two cuneiform, the 

 superior extremity of the principal metatarsal, and 

 that of the internal rudimentary metatarsal bones. 



The internal middle ligament (Fig. 93, 5) is com- 

 posed of two funicular cords, attached in common 

 beneath the preceding ligament to the internal tibial 

 tuberosity. These two fasciculi, exactly resembling 

 those of the external deep ligament, are directed 

 downward and backward, and terminate, one at the 

 astragalus, the other at the calcis. 



The internal deep ligament (Fig. 93, 4) is an ex- 

 tremely slender fasciculus, enveloped by the synovial 

 membrane ; it is often reduced to a thin shred, 

 scarcely distinct from the serous covering surround- 

 ing it. It is attached, in one direction, to the tibia 

 below the middle ligament ; in the other to the 

 astragalus, and nearly at the same point as the 

 superior fasciculus of the middle ligament. 



c. Anterior ligament. — This is a membraniform band formed of inter- 

 crossed fibres, stronger outwards than inwards, attached by its upper border 

 above and in front of the tibial surface, fixed by its inferior border to the 

 astragalus, the scaphoid and great cuneiform bones, and the astragalo- 

 metatarsal ligament ; it is confounded at its sides with the two superficial 

 lateral ligaments. Its internal face is lined by articular synovial mem- 

 brane, while the external is covered by the flexor of the metatarsus, the 

 anterior extensor of the phalanges, the anterior tibial artery, and several 

 large anastomosing veins from whose junction arises the anterior tibial 

 vein. 



d. Posterior ligament. — This is the second membraniform or capsular 

 band which protects the articulation posteriorly. It presents, in its centre. 



TARSAL ARTICULATIOHS; 

 EOUT VIEW. 



I, External deep ligament 

 of the tibio-tarsal ar- 

 ticulation ; 2, 2, Ex- 

 ternal superficial liga- 

 ment ; 4, Internal deep 

 ligament ; 5, Internal 

 middle ligament ; 6, In- 

 ternal superficial liga- 

 ment ; 7, Astragalo- 

 metatarsal ligament ; 8, 

 Small cuboido-cunean 

 ligament. — A, Pulley of 

 the astragalus ; B, Cu- 

 boidal insertion belong- 

 ing to the tendinous cord 

 of the flexor of the me- 

 tatarsus ; c, Vascular 

 canal of the tarsus. 



