r . INTERPHALANGEAL JOINTS. 303 
a ae Sp ee ae er 
series, and consist of scattered fibres passing from the cuboid to the bases of the 
two metatarsals. Some fibres, which are almost transverse, extend from the 
external cuneiform to the fifth metatarsal, and additional fibres reach the meta- 
tarsals in question from the long plantar ligament (calcaneo-cuboid). 
Occasionally the tarsal end of the external interosseous (cuneo-metatarsal) liga- 
ment is attached to the inner margin of the cuboid. 
The synovial membrane is restricted to this articulation, and merely sends a 
prolongation forwards between the opposing articulate aspects of the fourth and 
fifth metatarsal bases. 
INTERMETATARSAL JOINTS. 
The intermetatarsal articulations are found between adjacent lateral aspects of 
the bases of the four outer metatarsal bones. The articular facets are small, oval, 
or rounded surfaces which occupy only a limited portion of the flattened contiguous 
surfaces of the bones. Each joint is provided with a capsule, which, however, is not 
a complete investment, because the three joint cavities are in free communication 
on their proximal aspects with the tarso-metatarsal joint cavities—one with the 
outer and two with the middle. The definite fibres of each capsule are situated 
chiefly in the transverse direction. 
The dorsal ligaments (Fig. 229) are short bands which extend from one base to 
the other. 
The plantar (Fig. 230) and interosseous ligaments are similarly arranged, but the 
latter are the strongest and most important members of this series. 
The synovial membranes are extensions from those which line the outer and 
middle tarso-metatarsal joint cavities. 
Frequently a bursa is found between the bases of the first and second metatarsal bones. It 
produces an appearance of indistinct facetting upon these bones, and it may communicate with 
the inner tarso-metatarsal (cuneo-metatarsal) joint. 
The transverse metatarsal ligament (Fig. 230) les upon, and is attached to, the 
non-articular plantar aspects of the heads of all the metatarsal bones. It differs 
from the corresponding ligament in the palm in the fact that it binds all the 
metatarsal bones together, whereas in the palm the thumb is left free. It is 
closely associated with the plantar fibrous plates of the metatarso-phalangeal joints, 
to the plantar surfaces of which it contributes prolongations termed lgamenta 
accessoria plantaria. 
METATARSO-PHALANGEAL JOINTS. 
Each of these joints is a modified ball-and-socket in which a shallow cup upon the 
bases of the first phalanges receives the somewhat globular head of a metatarsal bone. 
Each joint retains a modified capsule (Figs. 228 and 230) which invests the 
joint. Its only distinct bands are the ligamenta collateralia. These are strong 
cord-like bands which are situated on the inner and outer sides of each joint, 
where they extend between adjacent rough surfaces. 
On the dorsal aspect ligaments distinct from the dorsal expansion of the ex- 
tensor tendons can hardly be said to exist. The plantar aspect of the capsule 
consists of a thick fibrous plate, which in the case of the great toe presents 
developed within it two large sesamoid bones. In the other toes this plate remains 
fibrous throughout, and is grooved on its plantar aspect for the accommodation of 
the long flexor tendons. It will thus be seen that the metatarso-phalangeal joints are 
constructed upon a plan very similar to that of the corresponding joints in the hand. 
A synovial membrane lines the capsule of each articulation. 
INTERPHALANGEAL JOINTS. 
Each toe possesses two interphalangeal joints except the great toe, which has 
only one. Not unfrequently in the little toe the distal joint is obliterated through 
ankylosis. All the joints of this series are uniaxial or hinge joints. The nature 
of the articular surfaces closely resembles the corresponding joints in the fingers. 
