PELVIC LIMBS 



765 



Fia. 582. 



Articulation. The ectocuneiform articulates with the scaphoid on 

 the proximal side, with the mesocuneiform and the second metatarsal 

 on the tibial side, with the third metatarsal on the distal side, and with 

 the cuboid on the fibular side. 



Ossification. The ectocuneiform is developed from one centre of 



ossification. 



THE CUBOID. 



General Description. The Cuboid is the bone on the outer, or 

 fibular, side of the distal row of the tarsus (Fig. 582). It lies distal 

 to the calcaneum and proximal to the fourth and 

 fifth rnetatarsals. The scaphoid and ectocunei- 

 form are on its inner or tibial side. It is a reg- 

 ular bone without processes, but deeply grooved 

 for the passage of a tendon. It has six surfaces, 

 whereof three are occupied by articular facets 

 for the contiguous bones mentioned, and the 

 other three are rougher for the attachment of 

 ligaments and muscles. The articular surfaces 



o 



are the proximal, the distal, and the tibial ; the 

 non-articular are the dorsal, the fibular, and the 

 plantar. 



The proximal surface (Fig. 583) is roughly 

 quadrilateral, somewhat wider from side to side 

 than high from the instep to the sole. Its dorsal 

 and tibial margins are nearly straight, and meet 

 at right angles. The tibio-plantar angle is 

 somewhat truncate, and the plantar border is 

 emarginate for most of its extent, but arcuate 

 at the fibulo-plantar angle, which is produced 

 downward. The fibular border is in general 

 slightly arcuate, but emarginate near the dorso- 

 fibular angle where the groove begins. The 

 proximal surface is smooth, and covered with 

 cartilage for articulation with the distal surface 

 of the calcaneum. It is not flat, but so twisted 

 that the tibial side faces toward the heel and the dorsum of the foot, 

 and the fibular part, with the produced lower outer angle, faces directly 

 toward the heel. 



POSITION OF CUBOID. 



