340 



PONES OF THE FOOT. 



facet last named separates it from the third ;md 

 largest one ; this is articulated with the facet 

 which is on the inferior surface of the body of 

 the astragalus; it is oval, convex, and its long 

 axis directed forwards and outwards. Imme- 

 diately in front of this articular facet there is a 

 hollow, rough, non-articular surface for the 

 insertion of the ligament which connects the 

 astragalus to the os calcis, and behind the facet 

 the remaining portion of the superior surface 

 of the bone is also non-articular, slightly exca- 

 vated from before backwards, varying in length 

 in different subjects, and on this variety de- 

 pends the diversity in the length of the heel. 

 b. The posterior surface, oval in its outline, 

 rough and fibrous in its inferior half, where the 

 tendo Achillis is inserted, smooth in its supe- 

 rior half where a bursa is placed, over which 

 the tendon glides, c. The inferior or plantar 

 surface, nearly equal in extent to the superior, 

 and in the natural position directed obliquely 

 upward and forwards. Here we find, in ex- 

 amining the parts from behind forwards, first, 

 two tubercles, upon which the heel rests in 

 standing, and which seem peculiarly to cha- 

 racterize the human heel-bone. These tuber- 

 cles are separated from each other by a depres- 

 sion; the internal one is greatly the larger it 

 affords attachment to the short flexor of the toes ; 

 the external one is small and pointed, and to it 

 are attached the abductor minimi digiti muscle 

 and the plantar fascia. Secondly, in front of 

 these tubercles the bone is very rough and flat to 

 within half an inch of its anterior margin, 

 where it is slightly grooved transversely. The 

 whole of this portion gives insertion to the 

 strong calcaneo-cuboid ligament, d. The ante- 

 rior or cuboid surface, which is entirely articu- 

 lar, triangular, with its base upwards, slightly 

 concave, and articulated with the cuboid bone. 

 e. The external surface, quite subcutaneous, 

 so that here the bone is greatly exposed to 

 injury, and may be easily got at for surgical 

 operation. Jt is slightly convex, its posterior 

 half being double the size of the anterior in ver- 

 tical measurement; at the anterior part of the 

 former there are two superficial grooves directed 

 obliquely forwards and downwards, separated 

 by a slightly prominent tubercle. The anterior 

 of these grooves gives passage to the tendon of 

 the peroneus brevis, the posterior to that of 

 the peroneus longus. f. The internal surface, 

 excavated in its whole extent, lodges the ten- 

 dons and nerves which are passing from the 

 back of the leg to the sole of the foot ; at the 

 junction of its anterior and posterior halves it 

 is overlapped by the sustentaculum, the inferior 

 surface of which is grooved by the tendon of 

 the long flexor of the great toe. 



3. Os ciiboideum, (os cubi/bnne, Fr. le cu- 

 boide, Germ, das Wurfelbein. ) This bone 

 forms the external one of the second row of 

 tarsal bones ; it is situated between the os 

 calcis behind and the fourth and fifth meta- 

 tarsal bones in front ; in point of size it ranks 

 next to the astragalus. Six surfaces may be 

 described upon it. a. The superior or dorsal 

 surface, forming an inclined plane, directed 

 downwards and outwards ; it is rough for liga- 



mentous insertion, b. The external surface, 

 more properly an edge, very limited in extent, 

 chiefly occupied bv the commencement of the 

 groove for the peroneus longus muscle, c. The 

 inferior or plantar surface, which in front pre- 

 sents a deep groove directed obliquely forwards 

 and inwards, parallel to the anterior edge, and 

 destined to lodge the tendon of the peroneus 

 longus. The posterior edge of this groove is 

 very prominent, and with the remainder of this 

 surface, which is rough, affords insertion to 

 the calcaneo-cuboid ligament, d. The internal 

 surface has at its upper and posterior part a 

 triangular plane articular facet for articulation 

 with the external cuneiform bone, and some- 

 times a smaller one for articulation with the 

 navicular; the rest of this surface is irregular 

 and rough for ligamentous insertion, e. The 

 anterior or metatursal surface is wholly arti- 

 cular, and is divided by a vertical line into two 

 facets, an outer one triangular and plane for 

 the fifth, and an inner one quadrilateral and 

 very slightly concave for the fourth metatarsal 

 bone. The external of these facets is inclined 

 obliquely outwards and backwards. /. The 

 posterior surface is oval, with its long axis 

 directed downwards and outwards; itis wholly 

 articular and adapted to the anterior surface of 

 the os calcis. 



4. Os scaphoideum (from crxafpi), navis, os 

 naviculare, Yr.tescaphoide, Germ. das Ku/inbein, 

 oder Sc/iiformige Knoc/ien,) forms the posterior 

 and internal bone of the second tarsal row, and 

 is placed between the three cuneiform bones in 

 front and the astragalus behind. It is oval in 

 shape, with its long axis directed obliquely 

 downwards and inwards ; the small end of the 

 oval is situated internally and inferiorly, and 

 presents a distinct prominence or process (tuber 

 ossis naviculuris), which gives insertion to some 

 fibres of the tendon of the tibialis posticus. 



Four surfaces may be described upon this 

 bone. a. The superior or dorsal surface, of 

 great extent, convex, very rough for the inser- 

 tion of ligaments, and perforated by foramina. 

 b. The inferior surface, irregularly concave, 

 and very rough, also affording insertion to 

 ligaments, c. The posterior surface, entirely 

 articular, oval and concave, adapted to the 

 head of the astragalus, although considerably 

 less in extent than it. This constitutes what is 

 called the glenoid cavity, d. The anterior sur- 

 face, also articular and convex, divided by two 

 lines which converge from above downwards, 

 into three triangular surfaces for articulation 

 with the three cuneiform bones. 



5. Omit cuneiformia (Fr. les os cuneiformes, 

 Germ. die. Kei/fonnigen Knodien.) These 

 bones are interposed between the navicular 

 bone behind and the three internal metatarsal 

 bones in front ; they are arranged in the form 

 of an arch, of which the middle cuneiform is 

 the central or key-bone. Each is very distinctly 

 wedge-shaped ; the two outer ones have the 

 acute edge directed downwards, but the inter- 

 nal one has it directed upwards. 



The internal cuneiform bone is at once dis- 

 tinguishable from the others by its great size. 

 By means of an oval concave articular surface, 



