160 TOPOGRAPHICAL ANATOMY OF 



between the neighbouring bones of the same row ; and (4) the tarso- 

 metatarsal articulation (articulatio tarso-metatarsea), between the distal 

 row of tarsal bones and the bases of the three metatarsals. 



The ligaments of the tarsal articulations may be classified as (1) 

 those that are common to the whole series of articulations, and 

 (2) those that join two or more bones together. The common 

 ligaments consist of a joint-capsule and two collaterals. 



Though it is customary to describe the fibrous layer of the joint-cajysule 

 (capsula articularis) as extending from the distal end of the tibia to the 

 proximal end of the metatarsus, that portion of it associated with the 

 talo-crural joint is most definite and spacious. The rest of it is firmly 

 adherent to the free surfaces of the tarsal bones, and blends most 

 intimately with the collateral and other ligaments, as well as with 

 tendons inserted in the immediate neighbourhood. That part of the 

 capsule attached to the plantar (posterior) surfaces of the tarsal bones 

 is of great strength, and reinforced by a cartilaginous plate, which assists 

 in the formation of the smooth groove down which the deep flexor 

 tendon plays. 



The synovial layer of the joint-capsule is divided into four sacs. 

 (1) The most capacious of these is between the tibia and the talus. On 

 the flexor (dorsal or anterior) aspect of the joint the membrane forms 

 a small diverticulum over the end of the tibia ; and behind the joint, 

 that is, on its plantar or extensor aspect, there is a larger diverticulum 

 extending for a short distance (4 or 5 cm.) upwards between the tibia 

 and the tendon of the flexor hallucis longus. (2) The second synovial 

 sac is associated with the joint formed by the tibial tarsal (talus), 

 fibular tarsal (calcaneus), central (scaphoid), and fourth tarsal (cuboid) 

 bones. (3) The third synovial membrane belongs to the joint between 

 the central (scaphoid) and the bones of the distal row ; (4) while the 

 fourth sac belongs to the tarso-metatarsal articulation. 



The most powerful ligaments of the tarsus are those that extend 

 from the tibia to the metatarsus (the two collateral ligaments) and 

 those that pass from the proximal row of tarsal bones to the 

 metatarsus (dorsal and plantar ligaments). 



The lateral collateral ligament (ligamentum collaterale fibulare 

 (laterale)) is composed of two strong bands, both of which arise from 

 the lateral malleolus. The more superficial and longer band is con- 

 nected with the talus, calcaneus, fourth tarsal (cuboid), and the third 

 and fourth metatarsal bones. The deeper, short ligament crosses the 

 foregoing obliquely to be attached to the talus and calcaneus. 



The medial collateral ligament (ligamentum collaterale tibiale 

 (mediale)) has its origin from the medial malleolus, and is also divisible 



