8 August, 1907.] Lameness in Horses. 



475 



Bog Spavin. 



Bog spavin is a distension of the capsule of the true hock joint with 

 synovia (joint oil). The condition exists most frequently in those horses 

 which have either very straight or very crooked hocks, and it is fairly 



^ '&• 79- Position of bog spavin 

 indicated by dotted line. (After 

 Hayes.) 



Fig. 78. External view of bones of near hind limb. i, Tibia; 2, calcaneum ; 

 3, astragalus ; 4, cuboid ; 5, cuneif orme magnum ; 6, cuneif orme medium ; 7, great 

 metatarsal (cannon) ; 8, external small metatarsal (splint) ; g, os suifraginis (long 

 pastern bone); lo, sesamoids; ii, os corona (short pastern bone); 12, os pedis 

 (coffin bone) ; 13, os naviculare (nxvicular bone) ; 14, wing of os pedis. (After 

 Strangways.) 



common in young cart horses when first put to work. The distension is 

 evidenced in the form of a soft elastic swelling, resembling that of 

 thoroughpin or windgall, standing out prominently on the inner aspect of 

 the hock towards the front. (See Figs. 8r, 82, and 83.) Like thoroughpin. 



