Tarsus and Metatarsus 



509 



The metatarsai bones have a more or less rectangular base, for 

 articulation with the cuneiforms and the cuboid, and a rounded head 

 for the first phalanx. The first metatarsai, like a phalanx, has its 

 epiphysis at the proximal end. 



Scheme showing ossification of tarsal bones, and of first and second metatarsai bones. (GRAY.) 



There is a vertical ridge on the inner side of the base of the first 

 metatarsai which can be felt beneath the skin ; close behind this is 

 the joint with the innermost cuneiform. This joint is exactly in 

 the middle of the length of the foot, the arch of the foot being almost 

 entirely behind it. In flat-foot (p. 502), therefore, when the arch has 

 given way and spread out, the length of that part of the foot which is 

 behind this joint greatly exceeds that which is in front of it. 



The base of the second metatarsai bone is firmly mortised amongst 

 the cuneiforms, and articulates with the middle cuneiform, its lateral 

 surfaces lying against the internal and external cuneiforms, a strong 

 interosseous ligament connecting it with the inner. 



The third metatarsai articulates with the external cuneiform ; and 

 the fourth and fifth articulate with the cuboid. The base of the fifth 

 has a large tuberosity, which bulges behind the joint with the 

 cuboid, so, to hit the joint, as in Key's amputation, the knife must 

 be slipped behind that tuberosity and then brought forwards and 

 inwards. 



The base of each of the three outer metatarsals articulates behind 

 by an oblique facet ; these joints have the same slant backwards 

 and outwards and the innermost of them is on the level of the joint 

 between the first metatarsai and the internal cuneiform. 



To draw the line of the tarso-metatarsal joints upon the un- 



