448 PRACTICAL ANATOMY. 



Describe the astragalus. (Fig. 315.) 



This bone has (i) a head, which articulates with the scaphoid bone ; (2) a 

 neck, by which the head is joined to the body of the bone ; (3) a bod}', which 

 has superior, inferior, internal, external, and posterior surfaces. 



Give tltc importance of each surface of the astragalus. 



(i)The superior surface articulates with the tibia ; (2) the external surface 

 articulates with the fibular malleolus ; (3) the internal surface articulates with 

 the tibial malleolus ; (4) the inferior surface articulates with the calcaneum ; (5) 

 the posterior surface has a groove for the flexor longus hallucis. 



Describe the calcaneinn or heel-bone. (Fig. 315.) 



This bone has six surfaces anterior, posterior, superior, inferior, internal, 

 and external. 



Give the importance of each surface. 



(i) The anterior surface articulates with the cuboid bone; (2) the posterior 

 surface has the tendo Achillis attached to it ; (3) the external surface has two 

 peroneal grooves and 'a tubercle between them ; (4) the internal surface has the 



FIG. 316. SECTION TO SHOW THE SYNOVIAL CAVITIES OK THE FOOT. 



I. Posterior calcaneo-astragaloid. 2. Calcaneo-cuboid. 3. Anterior calcaneo-astragalo-scapboid. 



4. Tarsal. 5. Cubo-metatarsal. 6. First metatarso-cuneiform. 



sustentaculum tali and a groove ; (5) the inferior surface has the three important 

 tubercles ; (6) the superior surface has an astragaloid articular surface. 



Name and give importance of the tubercles of the calcaneum. (Fig. 314.) 



(i) The inner tubercle gives origin to the abductor hallucis, the flexor brevis 

 digitorum, and the abductor minimi digiti ; (2) the outer tubercle gives origin 

 to the abductor minimi digiti, and to the inconstant abductor ossis metatarsi 

 quinti ; (3) the anterior tubercle gives attachment to the short plantar or cal- 

 caneo-cuboid ligament. 



Describe the scaphoid bone. (Fig. 316.) 



This bone articulates posteriorly with the head of the astragalus ; anteriorly 

 with the three cuneiform bones. The superior, inferior, and external surfaces art- 

 rough, for the attachment of ligaments. The internal surface has the tuberosity, 

 into which is inserted the tibialis posticus muscle. 



Describe the cuboid bone. (Fig. 316.) 



It has six surfaces : (i) The anterior articulates with the bases of the fourth 

 and fifth metatarsals ; (2) the posterior articulates with the calcaneum ; (3) the 

 internal articulates with the scaphoid (sometimes) and external cuneiform ; (4) 

 the superior is rough, for attachment of ligaments ; (5) the inferior has a groove 



