308 THE ARTICULATIONS 



(a) The Medial Tarso-metatarsal Joint 



Class. — Diarihrosis. Subdivision. — A rthrodia. 



A complete articular capsule unites the first metatarsal with the first cunei- 

 form, the fibres of which are very thick on the inferior and medial aspects; those 

 on the lateral side pass from behind forward in the interval between the interos- 

 seous ligaments which connect the two bones forming this joint with the second 

 metatarsal. The ligament on the plantar aspect is by far the strongest, and 

 blends at the cuneiform bone with the cuneo-navicular ligament. 



(6) The Intermediate Tarso-metatarsal Joint 

 Class. — Diarthrosis. Subdivision. — A rthrodia . 



Into this union there enter the three cuneiform and second and third meta- 

 tarsal bones, which are bound together by the following ligaments (supplementary 

 to the articular capsule) : dorsal, plantar, interosseous. 



The dorsal ligaments. — 1. Some short fibres cross obliquely from the lateral edge of the 

 first cuneiform bone to the medial border of the base of the second metatarsal bone; they take 

 the place of a dorsal metatarsal ligament, which is wanting between the first and second meta- 

 tarsal bones. 



2. Between the second cuneiform and the base of the second metatarsal bone some fibres 

 run directly forward. 



3. The third cuneiform is connected with (1) the lateral corner of the second metatarsal 

 bone by a narrow band passing obliquely medially; (2) with the third metatarsal by fibres 

 passing directly forward; and (3) with the fourth metatarsal by a short band passing obliquely 

 laterally to the medial edge of its base. 



The plantar ligaments. — A strong ligament unites the first cuneiform and the bases of the 

 second and third metatarsal bones. The tibialis posterior is inserted into these bones close 

 beside it. Other slender ligaments connect the second cuneiform with the second, and the third 

 cuneiform with the third metatarsal bones. 



The interosseous ligaments. — (1) A strong broad interosseous ligament extends between 

 the lateral surface of the first cuneiform and the medial surface of the base of the second meta- 

 tarsal bone. It is attached to both bones below and in front of the articular facets, and sepa- 

 rates the intermediate [from the medial tarso-metatarsal joint. (2) A second band is attached 

 behind to a fossa on the anterior and lateral edge of the third cuneiform and to the interosseous 

 ligament between it and the cuboid, and passes horizontally forward to be attached to the whole 

 depth of the fourth metatarsal bone behind its medial facet, and to the opposed surfaces of the 

 third and fourth below the articular facets upon their sides. It separates the middle tarso- 

 metatarsal, and intermetatarsal between the third and fourth bones, from the cubo-metatarsal 

 joint. It is more firmly connected with the third bone than with the fourth. (3) A slender 

 ligament composed only of a few fibres often passes from a small tubercle on the medial and an- 

 terior edge of the third cuneiform to a groove on the lateral edge of the second metatarsal bone 

 between the two facets upon their sides. 



The synovial membrane is prolonged forward from that of the naviculari-cuneiform and 

 inter-cuneiform articulations. 



The arteries for the tarso-metatarsal joints are derived: — (1) for the medial, from the dor- 

 sahs pedis and medial plantar; (2) for the rest, twigs from the arcuate and deep plantar arch. 



The nerve-supply comes from the deep peroneal and plantar nerves. 



The movements permitted at these joints are flexion and extension of the metatarsus on 

 the tarsus; and at the medial and lateral divisions, slight adduction and abduction. In the 

 lateral, the side-to-side motion is freer than in the medial joint, and freest between the fifth 

 metatarsal bono and the cuboid. In the medial joint, flexion is combined with slight abduction 

 and extension with alxluction. 



There is also a little gliding, which allows the transverse arch to be increased or diminished 

 in depth; the medial and lateral two bones sliding downward, and the two middle a little 

 upward, when the arch is increased; and vice versa when the arch is flattened. 



(c) The Lateral or Cubo-metatarsal Joint 



Class. — Diarthrosis. Subdivision. — A rthrodia. 



The bones comprising this joint are the fourth and fifth metatarsal and the 

 anterior surface of the cuboid, firmly connected on all sides by the articular cap- 

 sule, strengthened by the following ligaments: — 



Dorsal. Plantar. Interosseous. 



The plantar cubo-metatarsal ligament is a l)roa(l, well-marked ligament, which extends 

 from the culjtjid beliind to the leases of the fourth and fifth metatarsal bones in front. It is 



