THE TIBIOTARSAL ARTICULATION 



343 



The anterior tibiotarsal ligament (ligamentum talotibiale anterius) is a broad, 

 thin, membranous layer, attached, above, to the anterior margin of the lower 

 extremity of the tibia; below, to the margin of the astragalus, in front of its 

 articular surface. It is in relation, in front, with the Extensor tendons of the 

 toes, with the tendons of the Tibialis anticus and Peroneus tertius, and the 

 anterior tibial vessels and nerve; behind, it lies in contact with the synovial 

 membrane. 



The posterior tibiotarsal ligament (ligamentum talotibiale posterius) is very 

 thin, and consists principally of transverse fibres. It is attached, above, to the 

 margin of the articular surface of the tibia, blending with the transverse tibio- 

 fibular ligament; below, to the astragalus, behind its superior articular facet. 

 Externally, where a somewhat thickened band of transverse fibres is attached 

 to the hollow on the inner surface of the external malleolus, it is thicker than 

 internally. 



INTEROSSEOUS 

 LIGAMENT 



SYNOVIAL 

 ADIPOSE PAD 



PERONCUS 

 BREVIS MUSCLE 



PERONEU 

 LONGUS MUSCLE 



INTERNAL LATFRAL 

 LIGAMENT 

 TIBIALIS POSTICUS 



INTEROSSEOUS CAL- 

 CANEO-ASTRAGALCID 

 LIGAMENT 

 FLEXOR LONGUS 

 DIGITORUM 

 FLEXOR LONGUS 

 'HALLUCIS 

 POSTERIOR 

 TIBIAL VESSELS 



FIG. 275. Frontal section through the ankle-joint and the calcaneo-astragaloid articulation. 



(Poirier and Charpy.) 



The internal lateral or deltoid ligament (ligamentum calcaneotibiale) (Figs. 

 275 and 276) consists of a superficial and a deep set of fibres; the superficial set 

 constitute a strong, flat, triangular band, which is attached, above, to the apex 

 and to the anterior and posterior borders of the inner malleolus. The most 

 anterior fibres pass forward to be inserted into the scaphoid bone and the inferior 

 calcaneoscaphoid ligament; the middle descend almost perpendicularly to be 

 inserted into the sustentaculum tali of the os calcis; and the posterior fibres 

 pass backward and outward to be attached to the inner side of the astragalus. 

 The deep set is attached, above, to the notch of the inner malleolus, and, below, 

 to the inner side of the astragalus. This ligament is covered by the tendons 

 of the Tibialis posticus and Flexor longus digitorum muscles. 



The external lateral ligament (ligamenta talofibularia et calcaneofibulare) 

 (Figs. 276 and 277) consists of three distinctly specialized fasciculi of the capsule, 

 taking different directions and separated by distinct intervals; for which reason 

 it is divided by some anatomists into three distinct ligaments, and so described. 1 



1 Humphry. On the Skeleton, p. 559. 



