246 



SPECIAL ANATOMY OF THE SKELETON 



of a deep groove on its under surface, for the tendon of the Peroneus longus muscle. 

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

 The nonarticular surfaces are the dorsal, plantar, and external. The dorsal 

 surface, directed upward and outward, is rough, for the attachment of numerous 

 ligaments. The plantar surface presents in front a deep groove, the peroneal 

 groove (sulcus m. peronei longi), which runs obliquely from without, forward and 

 inward; it lodges the tendon of the Peroneus longus, and is bounded behind by 

 a prominent ridge, to which is attached the long calcaneocuboid ligament. The 

 ridge terminates externally in an eminence (tuberositas ossis cuboidei), the surface 

 of which presents a convex facet, for articulation with the sesamoid bone of the 

 tendon contained in the groove. The surface of bone behind the groove is rough, 

 for the attachment of the short plantar ligament, a few fibres of origin of the 

 Flexor brevis hallucis, and a fasciculus from the tendon of the Tibialis posticus. 

 The external surface, the smallest and narrowest of the three, presents a deep 

 notch formed by the commencement of the peroneal groove. 



For ext. cuneiform For 4th metatarsal 



Occasional facet 

 for navicular 



Groove for Tuberosity For os calcis 

 Peroneus 

 A longus B 



FIG. 196. The left cuboid. A. Antero-internal view. B. Postero-external view. 



The articular surfaces are the posterior, anterior, and internal. The posterior 

 surface is smooth, triangular, and concavo-convex, for articulation with the 

 anterior surface of the os calcis. The anterior surface, of smaller size, but also 

 irregularly triangular, is divided by a vertical ridge into two facets ; the inner one, 

 quadrilateral in form, articulates with the fourth metatarsal bone; the outer one, 

 larger and more triangular, articulates with the fifth metatarsal. The internal 

 surface is broad, rough, irregularly quadrilateral, presenting at its middle and 

 upper part a smooth oval facet, for articulation with the external cuneiform bone; 

 and behind this (occasionally) a smaller facet, for articulation with the navicular; 

 it is rough in the rest of its extent, for the attachment of strong interosseous liga- 

 ments. 



To ascertain to which foot the bone belongs, hold it so that its under surface, marked by the 

 peroneal groove, looks downward, and the large concavo-convex articular surface backward 

 toward the holder: the narrow nonarticular surface, marked by the commencement of the 

 peroneal groove, will point to the side to which the bone belongs. 



Articulations. With/owr bones the os calcis, external cuneiform, and the fourth and fifth 

 metatarsal bones; occasionally with the scaphoid. 



Attachment of Muscles. Part of the Flexor brevis hallucis and a slip from the tendon of 

 the Tibialis posticus. 



Scaphoid or Navicular Bone (os naviculare pedis) (Fig. 197). The scaphoid is 

 situated at the inner side of the tarsus, between the astragalus behind and the 

 three cuneiform bones in front. It may be distinguished by its form, being con- 

 cave behind, convex and subdivided into three facets in front. 



The anterior surface, of an oblong form, is convex from side to side, and sub- 

 divided by two ridges into three facets, for articulation with the three cuneiform 

 bones. The posterior surface is oval, concave, broader externally than internally, 



