88 THE ANATOMY OP THE HORSE. 



large and small cuneiforms, and large and internal small metatarsal 

 bones. The middle division is of intermediate size ; and in order to 

 expose it, the superficial division must be cut, and dissected downwards. 

 Above it is attached to the internal tuberosity of the tibia ; and, passing 

 downwards and backwards, it is inserted by distinct slips into the 

 astragalus and os calcis. The deep division is very slender, and 

 stretches between the tibia and the astragalus, under cover of the middle 

 fasciculus, which must be removed in order to expose it. 



The Antenor Ligament is membranous and four-sided. It is fixed 

 above to the tibia ; and below to the astragalus, scaphoid, cuneiform 

 magnum, and astragalo-metatarsal ligament ; while on each side it 

 blends with the lateral ligament. The posterior surface of the ligament 

 is lined by the synovial membrane of the joint. The anterior surface 

 is related to the anterior tibial vessels, and to the flexor metatarsi 

 and extensor pedis tendons. Towards its inner side the ligament 

 is unsupported ; and hence, when the synovial membrane becomes 

 dropsical, the distension shows at that point, constituting a "bog- 

 spavin." 



The Posiemor Ligament is of a similar form to the preceding. It is 

 fixed above to the tibia, below to the astragalus and os calcis, and at 

 the sides to the lateral ligaments. Its anterior surftxce supports the 

 synovial membrane of the joint ; Avhile the posterior is lined by the 

 synovial membrane of the tarsal sheath, and presents a fibro-cartila- 

 ginous thickening where the perforans tendon plays over it. This tendon 

 affords support to the posterior ligament, which therefore does not 

 bulge so readily as the anterior ligament ; but in a case of extreme 

 distension of the synovial membrane, the swelling shows itself at the 

 back of the joint. 



The Synovial 31emh-ane is supported by the anterior, posterior, and 

 lateral ligaments ; and it communicates with the synovial membrane 

 that lubricates the articulations between the os calcis and the astragalus 

 on the one hand, and the cuboid and scaphoid on the other. It also 

 sometimes supplies the two upper facets between the os calcis and 

 astragalus. 



Directions. — The anterior and posterior ligaments should be incised 

 in order to expose the synovial membrane ; and, thereafter, these and 

 the lateral ligaments should be cut away. This will effect the separa- 

 tion of the tibia ; and the next group of ligaments may then be 

 examined. 



The following ligaments can hai'dly be classified as belonging specially 

 to any one articulation or set of articulations. For the most part they 

 bind together the series of tarsal bones, and also serve to bind these to 

 the metatai-sal bones. 



The Astragalo-metatarsal Ligament. — This is a flat, radiating ligament. 



