I 



ARTICULATIONS OF THE DIGITS 359 



Synovial Membranes (Fig. 360). The synovial membranes between the second and third, 

 and the third and fourth metatarsal bones are part of the great tarsal synovial membrane; that 

 between the fourth and fifth is a prolongation of the synovial membrane of the cuboideometatarsal 

 joint. 



Movements. The movement permitted between the tarsal ends of the metatarsal bones 

 is limited to a slight gliding of the articular surfaces upon one another. 



The heads of all the metatarsal bones are connected together by the transverse 

 metatarsal ligament. 



The Transverse Metatarsal Ligament. The transverse metatarsal ligament is a 

 narrow band which runs across and connects together the heads of all the meta- 

 tarsal bones; it is blended anteriorly with the plantar (glenoid) ligaments of the 

 metatarsophalangeal articulations. Its plantar surface is concave where the 

 Flexor tendons run below it; above it the tendons of the Interossei pass to their 

 insertions. It differs from the transverse metacarpal ligament in that it connects 

 the metatarsal to the others. 



The Synovial Membranes in the Tarsal and Tarsometatarsal Joints -(Fig. 360). The synovial 

 membranes found in the articulations of the tarsus and metatarsus are six in number: one for 

 the talocalcaneal articulation; a second for the talocalcaneonavicular articulation; a third for 

 the calcaneocuboid articulation; and a fourth for the cuneonavicular, intercuneiform, and cuneo- 

 cuboid articulations, the articulations of the second and third cuneiforms with the bases of the 

 second and third metatarsal bones, and the adjacent surfaces of the bases of the second, third, 

 and fourth metatarsal bones; a fifth for the first cuneiform with the metatarsal bone of the great 

 toe; and a sixth for the articulation of the cuboid with the fourth and fifth metatarsal bones. 

 A small synovial cavity is sometimes found between the contiguous surfaces of the navicular 

 and cuboid bones. 



VIII. Metatarsophalangeal Articulations (Articulationes Metatarsophalangese). 



The metatarsophalangeal articulations are of the condyloid kind, formed by 

 the reception of the rounded heads of the metatarsal bones in shallow cavities 

 on the ends of the first phalanges. 



The ligaments are the plantar and two collateral. 



The Plantar Ligaments (ligamenta accessoria plantaria; glenoid ligaments of Cru- 

 veilhier). The plantar ligaments are thick, dense, fibrous structures. They are 

 placed on the plantar surfaces of the joints in the intervals between the collateral 

 ligaments, to which they are connected ; they are loosely united to the metatarsal 

 bones, but very firmly to the bases of the first phalanges. Their plantar surfaces 

 are intimately blended with the transverse metatarsal ligament, and grooved for 

 the passage of the Flexor tendons, the sheaths surrounding which are connected 

 to the sides of the grooves. Their deep surfaces form part of the articular facets 

 for the heads of the metatarsal bones, and are lined by synovial membrane. 



The Collateral Ligaments (ligamenta collateralia; lateral ligaments) .The collat- 

 eral ligaments are strong, rounded cords, placed one on either side of each joint, 

 and attached, by one end, to the posterior tubercle on the side of the head of the 

 metatarsal bone, and, by the other, to the contiguous extremity of the phalanx. 



The place of dorsal ligaments is supplied by the Extensor tendons on the dorsal 

 surfaces of the joints. 



Movements. The movements permitted in the metatarsophalangeal articulations are flexion, 

 extension, abduction, and adduction. 



IX. Articulations of the Digits (Articulationes Digitorum Pedis; Articulations of 



the Phalanges). 



The interphalangeal articulations are ginglymoid joints, and each has a plantar 

 and two collateral ligaments. 



The arrangement of these ligaments is similar to that in the metatarsophalangeal 

 articulations; the Extensor tendons supply the places of dorsal ligaments. 



