THE ARTICULATIONS OF THE FOOT. 195 



and a strong interosseous ligament, which intervenes between their contiguous sur- 

 faces. When the bones touch, which is not always the case, they present two small 

 articulating surfaces, which are covered with cartilage and have between them an 

 offset of the adjacent naviculo-cuneiform synovial cavity. 



Naviculo-cuneiform articulation. The navicular articulates with the three 

 cuneiform bones by the smooth facets on its anterior surface, forming one continuous 

 joint. They are united by dorsal ligaments, passing from the upper surface of the 

 navicular to the first, second and third cuneiform bones, and by plantar ligaments, 

 which are similarly disposed on the under surface of the bones, but these are con- 

 tinuous with, or offsets from, the tendon of the tibialis posticus muscle. 



Cubo- cuneiform articulation. The cuboid and the external cuneiform bones 

 are connected by a dorsal ligament, which is a thin fasciculus of transverse fibres ; 



INTEROSS. ASTRAG. CALC. UIGT. 



EXT. CALC. NAV. LIGT. 



Fig. 223. SECTION OF THE FOOT, SHOWING THE SYNOVIAL CAVITIES OF THE TARSAL AND TARSO- 



METATARSAL ARTICULATIONS. (Gr. D. T.) 



The section is carried nearly vertically through the astragalus, obliquely upwards and inwards across 

 the other bones. 1, posterior astragalo-calcaneal articulation ; 2, astragalo-calcaneo-navicular articula- 

 tion ; 3, calcaneo-cuboid articulation ; 4, naviculo-cuneiform articulation, the common synovial cavity 

 extending forwards to the articulations between the cuneiform and the second and third nietatarsal 

 bones ; 5, cubo-cuneiform articulation (this is frequently continuous with the foregoing) ; 6, cubo- 

 metatarsal articulation (this sometimes communicates with the adjoining cuneo-metatarsal joint) ; 7, 

 internal cuneo-metatarsal articulation. 



a plantar ligament, the fibres of which are also transverse and rather indistinct ; and 

 a bundle of interosseous fibres. Between the two bones an articulation is formed 

 by cartilaginous surfaces ; it is provided sometimes with a separate synovial 

 sac, at others with an offset from that which belongs to the naviculo-cuneiform 

 articulation. 



The three cuneiform bones are connected by transverse dorsal ligaments and 

 strong interosseous fibres, the latter being their most efficient uniting structures. 

 The synovial cavity of the naviculo-cuneiform articulation sends forwards two 

 processes between these bones. 



ARTICULATIONS OF THE TARSUS WITH THE METATARSUS. The four anterior 

 bones of the tarsus, viz., the three cuneiform and the cuboid, articulate with the 

 metatarsal bones ; and as the first and third cuneiform bones project beyond the 

 middle one, and the third cuneiform beyond the cuboid bone, the anterior surface 

 of the tarsus is very irregular. The first metatarsal bone articulates with the 



VOL. II. O 



