126 CUNEIFORM AND CUBOID BONES. 



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 upwaids and the 

 long articular border forwards, the concave surface will point to the side 

 corresponding with the foot to which it belongs. 



The convex surface is internal and free, and assists in forming the inner 

 border of the foot ; the concave is external, and in apposition with the 

 middle cuneiform and second metatarsal bone ; the long border articulates 

 with the metatarsal bone of the great toe, and the short border with the 

 scaphoid bone. The small extremity (edge) is sharp, and the larger ex- 

 tremity (base) rounded into a broad tuberosity. 



Articulations. With four bones; scaphoid, middle cuneiform, and 

 first two metatarsal bones. 



Attachment of Muscles. To the tibialis anticus, and posticus. 



The MIDDLE CUNEIFORM is the smallest of the three; it is wedge- 

 shaped, the broad extremity being placed upwards, and the sharp end 

 downwards in the foot. It presents for examination four articular sur- 

 faces and two extremities. The anterior and posterior surfaces have 

 nothing worthy of remark. One of the lateral surfaces has a long arti- 

 cular facet, extending its whole length, for the internal cuneiform ; the 

 other has only a partial articular facet for the external cuneiform bone. 



If the bone be held so that the square extremity look upwards, the 

 broadest side of the square being towards the holder, the small and partial 

 articular surface will point to the side to which the bone belongs. 



Articulations. With four bones ; scaphoid, internal and external 

 cuneiform, and second metatarsal bone. 



Attachment of Muscles. To the flexor brevis pollicis. 



The EXTERNAL CUNEIFORM is intermediate in size between the two 

 preceding, and placed, like the middle, with the broad end upwards and 

 the sharp extremity downwards. It presents for examination five surfaces, 

 and a superior and inferior extremity. The upper extremity is flat, of an 

 oblong square form, and bevelled posteriorly, at the expense of the outer 

 surface, into a sharp edge. 



If the bone be held so that the square extremity look upwards and the 

 sharp border backwards, the bevelled surface will point to the side corre- 

 sponding with the foot to which the bone belongs. 



Articulations. With six bones; scaphoid, middle cuneiform, cuboid, 

 and second, third, and fourth metatarsal bones. 



Attachment of Muscles. To the flexor brevis pollicis. 



The CUBOID BONE is irregularly cuboid in form, and marked upon its 

 under surface by a deep groove, for the tendon of the peroneus longus 

 muscle. It presents for examination six surfaces, three articular and 

 three non-articular. The non-articular surfaces are the superior, which is 

 slightly convex, and assists in forming the dorsum of the foot; the inferior, 

 marked by a prominent ridge, the tuberosity, and a deep groove for the 

 tendon of the peroneus longus; and an external, the smallest of the whcle, 

 and deeply notched by the commencement of the peroneal groove. The 

 articular surfaces are, the posterior, which is of large size, and concavo- 

 convex, to articulate with the os calcis ; anterior, of smaller size, divided 



