768 MAMMALIAN ANATOMY 



The flbular surface is also rectangular, and is divided into two 

 parts by an oblique groove which begins near the dorsal and proximal 

 borders and runs to the disto-plantar angle. The portion in front of 

 the groove is smaller than the portion behind, which is much more 

 prominent and is continued on the plantar surface as a broad ridge, 

 namely, the tuberosity of the cuboid. This ridge runs from near the 

 proximo-fibular angle to the distal part of the tibial margin. In 

 front of the ridge is the continuation of the groove already mentioned 

 for the tendon of the peroneus longus. On the ridge is the common 

 origin of the adductor indicis, the adductor minimi digiti, and the 

 opponens minimi digiti. Behind the ridge the plantar surface is 

 concave, depressed, and rough for ligamentous insertion. The distal 

 border of the fibular surface is flattened, and articulates with the base 

 of the fifth metatarsal. 



Nomenclature. Cuboid is compounded of cubus, a cube, and 

 eides, like. Os cuboideum is very generally used, also, less frequently, 

 cuboides. The cuboid is formed by the union of the tarsalia IV. and 

 V. of comparative anatomists. The Germans use das Wurfelbein, the 

 French le cubo'ide. 



Determination. The cuboid is known by its oblong, rectangular 

 form and by the deep groove on the fibular and plantar surfaces. 

 When the smooth dorsal surface is held uppermost, and the distal 

 surface is toward the student, the rough tibial surface points to the 

 side to which the bone belongs. 



Articulation. The cuboid articulates proximally with the calca- 

 neum ; on the tibial side with the scaphoid and the ectocuneiform ; on 

 the fibular side slightly with the fifth metatarsal bone ; and distally 

 with the fourth and fifth metatarsal bones. 



Muscular Attachments. A part of the extensor brevis digi- 

 torum arises from the dorsal surface, the adductores minimi digiti 

 and indicis and the opponens minimi digiti from the palmar surface, 

 proximal to the groove for the peroneus longus tendon. 



Ossification. The cuboid is developed from one centre of ossifi- 

 cation. 



THE METATARSUS. 



General Description. The Metatarsus lies between the tarsus 

 and the digits, and forms what corresponds to the instep and part of 

 the sole of the human foot (Fig. 587). It is composed of four long 



