352 ANATOMY AND PHYSIOLOGY OF THE HOUSERS FOOT. 
navicular bone, where it unites with its fellow of the opposite 
side; in this way it forms a kind of complementary pad, 
ring, or bourrelet, as the French hippotomists have named it, 
that increases the articular surface of that bone. This fibrous 
ring (fig. 8 ,j), which is closer and denser than the ligaments 
composing it, is reinforced by additional fibres that endow it 
with a considerable degree of thickness, more particularly at 
the extremities of the navicular bone. It is an apparent con- 
tinuation of some of the fasciculi from this bourrelet which 
constitutes to some extent the basis of the membrane covering 
the lower face of the bone, and which has been erroneously 
described as hyaline cartilage. The posterior lateral ligament, 
outside this ring, sends off a short bundle of fibres to the inner 
face and base of the lateral cartilage, which blend themselves 
with the fibres of that body and those of the anterior lateral 
ligament. It also throws out a small band from the extremity 
of the navicular bone, which is inserted into the inner face of 
the retrossal process, and which, from its situation, tends to 
strengthen the ligament next to be described, and in this 
way assures the solidity of union between the pedal and 
navicular bones. 
The inferior or interosseous ligament (fig. 8, m) is single, 
and is composed of short unequal fibres that pass from the 
roughened lower border of the navicular bone to the posterior 
and inferior, or solar surface of the pedal bone. It is widest 
in the middle and narrowest at the extremities of the bone ; 
its fibres are arranged in small parallel bundles, generally 
somewhat apart, leaving only a thin fibrous membrane 
between ; in the middle and at each end it is usually thickest, 
and its fibres are continuous with those of the membrane 
covering the lower or posterior face of the navicular bone. 
In the fore foot it is strongest in the centre, and appears as 
a thick bundle of fibres that arise from a prominence in the 
middle of the semilunar ridge, and pass up to the lower end 
of the transverse ridge of the navicular bone to cover its 
surface. This is the ligament that fixes the lower border of 
that bone to the os pedis and prevents its posterior surface 
tilting upwards in sudden flexion of the limb. 
We have now briefly glanced at the arrangement of the 
ligaments of the foot, and have, perhaps, seen enough to 
convince us of the complexity of their disposition being more 
apparent than real, and that, by their situation, structure, 
union with each other or with tendons or cartilages, this 
organ is placed at a great advantage, so far as its retentive or 
contentive apparatus is concerned. We have only now to 
hurriedly examine the disposition of the tendons of the foot. 
