THE LOWER LIMB 



58^ 



and a certain amount of abduction or eversion of the foot takes place. When 

 a person stands erect with both feet upon the ground, abduction or eversion 

 is prevented by the astragalo-calcaneal Ugaments. If, however, the spring 

 ligament is in a weak condition, the tendon of the tibialis posticus is not of 

 itself sufficient to prevent displacement of the head of the astragalus down- 

 wards and inwards. Displacement accordingly takes place in that direction, 

 and so the condition known as fiat foot (pes planus) is produced. 



At the calcaneo-cuboid joint, besides the movements of flexion and exten- 

 sion combined with adduction and abduction, movement takes place down- 

 wards and inwards, or upwards and outwards. The astragalo-navicular and 



- Tuber Calcis 



Groove for Flexor Longus 

 Hallucis 



Sustentaculum Tali^ 



External Calcaneo- 

 navicular Ligament 



Tibialis Posticus _ 



Inferior Calcaneo-^ 

 aavicular (Spring) 

 Ligament 

 Short Plantar Ligament _ 



Naviculo-cuboid Ligament — 



Navicular Bone \ 



Naviculo-cuneiform f " 

 Ligaments ( _ 



Internal Cuneiform , 

 Bone 



Insertion of Peroneus 



Longus 



Capsule of ist Tarso 



metatarsal Joint 



.Long Plantai Ligament 



_, Peroneus Longus 

 Peroneus Brevis 



- Cubo-mctatarsal 

 Ligament 



Fig. 270. — Ligaments of the Right Foot (Pl.^ntar Aspect). 



calcaneo-cuboid joints together constitute the transverse tarsal articulation, 

 the direction of which is in a straight Une across the foot. It is at this trans- 

 verse tarsal joint where disarticulation is performed in Chopart's operation. 



IV. Naviculo-cuboid Joint. — ^This belongs to the class diarthrosis, 



and to the subdivision arthrodia, but only in those cases where the 

 two bones articulate directly with each other by faceted surfaces. 

 The ligaments are dorsal, plantar, and interosseous. 

 The dorsal ligament passes from the outer part of the dorsal 



