ii8 THE SURGICAL ANATOMY OF THE HORSE 



formed between the tarsal and metatarsal bones. The bones con- 

 cerned then are the cuboid, cuneiform magnum, and cuneiform parvum 

 above, and the large and two small metatarsal bones below. 



Pouches are sent downwardly from this membrane to supply the 

 articulations formed between the upper end of the large and two small 

 metatarsal bones. Towards the inner side of the joint it sends 

 upwardly a small pouch to supply the articulation formed between 

 the two cuneiform bones, whilst more outwardly, and towards the 

 front ot the joint, another pouch is sent upwards which supplies the 

 anterior of the two articulations formed between the cuboid and 

 cuneiform magnum. 



From our description of the above three chief synovial membranes 

 it will be seen that there are certain small articulations which are 

 not supplied by them. For the supply of the articulations referred 

 to there is a fourth synovial membrane, which is very much smaller 

 than those described. This is the scaphoido-cunean, so called because 

 it is mainly taken up in supplying the joint formed between the 

 scaphoid and cuneiform magnum. Upwardly it sends a prolongation 

 to supply the posterior cuboido-scaphoid articulation, whilst down- 

 wardly a small diverticulum is sent which lubricates the posterior 

 articulation formed between the cuboid and the cuneiform magnum. 



Tendons playing over the Joint. — The tendons of the superficial 

 and deep divisions of the flexor metatarsi muscle play over the 

 superficial face of the anterior common ligament. The tendon of the 

 superficial portion forms a kind of ring, through which the tendon 

 of the deep division makes its appearance. The latter tendon then 

 divides into two portions, one of which takes a vertical course to be 

 inserted into the anterior face of the upper extremity of the large 

 metatarsal bone, whilst the other portion runs downwards and inwards 

 to be inserted into the cuneiform parvum. The tendon of the super- 

 ficial portion of this muscle also splits into two divisions, one of 

 which runs downwards to become attached to the large metatarsal. 



