SCAPHOID INTERNAL CUNEIFORM. 95 



is convex and rough, and bounded posteriorly by the two inferior 

 tuberosities, of which the internal is broad and large, and the 

 external smaller and prominent. The external surface is convex 

 and subcutaneous, and marked towards its anterior third by 

 two grooves, often separated by a tubercle, for the tendons of 

 the peroneus longus and brevis. The internal surface is concave 

 and grooved, for the tendons and vessels which pass into the sole of 

 the foot. At the anterior extremity of this surface is a projecting 

 process, which supports the anterior articulating surface for the as- 

 tragalus, and serves as a pulley to the tendon of the flexor longus 

 digitorum. Upon the anterior extremity is a flat articular surface, 

 surmounted by a rough projection, which affords one of the guides 

 to the surgeon in the performance of Chopart's operation. The 

 posterior extremity is prominent and convex, and constitutes the 

 posterior tuberosity ; it is smooth for the upper half of its extent, 

 where it corresponds with a bursa ; and rough below, for the inser- 

 tion of the tendo Achillis ; the lower part of this surface is bounded 

 by the two inferior tuberosities. 



Articulations. With two bones ; the astragalus and cuboid. 



Attachment of Muscles. To nine ; by the posterior tuberosity, to 

 the tendo Achillis and plantaris ; by the inferior tuberosities and 

 under surface, to the abductor pollicis, abductor minimi digiti, flexor 

 brevis digitorum, flexor accessorius, and flexor brevis pollicis, and 

 to the plantar fascia ; and by the external surface, to the extensor 

 brevis digitorum. 



The SCAPHOID bone may be distinguished by its boat-like figure, 

 concave on one side, and convex with three facets upon the other. 

 It presents for examination an anterior and posterior surface, a supe- 

 rior and inferior border, and two extremities one broad, the other 

 pointed and thick. The anterior surface is convex, and divided into 

 three facets, to articulate with the three cuneiform bones ; and the 

 posterior concave, to articulate with the rounded head of the astra- 

 galus. The superior border is convex and rough, and the inferior 

 somewhat concave and irregular. The external extremity is broad 

 and rough, and the internal pointed and projecting, so as to form a 

 tuberosity. 



If the bone be held so that the convex surface with three facets 

 look forwards, and the convex border upwards, the broad extremity 

 will point to the side corresponding with the foot to which the bone 

 belongs. 



Articulations. With four bones ; astragalus and three cuneiform 

 bones. 



Attachment of Muscles. To the tendon of the tibialis posticus. 



The INTERNAL CUNEIFORM may be known by its irregular wedge- 

 shape, and by being larger than the two other bones bearing the 

 same name. It presents for examination a convex and a concave 

 surface, a long and a short articular border, and a small and a 

 large extremity. 



Place the bone so that the small extremity may look upwards and 



