THE PLANTAK CUSHION AND BULBS. 



49 



it into two distinct halves, which, as they serve as bases to the 

 so-called bulbs of the foot, and for the most part are only 

 covered by skin, have received the name of the sensitive bulbs. 



The cellular bulbs consist principally of yellow, elastic or 

 fibrous tissue, combined to form elastic membranes, elastic cords 

 of varying thickness, bundles, 

 or spherical masses. The bulbs 

 contain little white fibrous tissue, 

 and are, therefore, the softest 

 part of the entire plantar 

 cushion. From them, on either 

 side, runs a strong elastic cord 

 in a forward and upward di- 

 rection towards the lower end 

 of the suffraoinis bone, accom- 

 panying a similar elastic cord, 

 which arises more from the an- 

 terior part of the plantar cushion 

 and inner surface of the lateral 

 cartilage. As this elastic cord 

 serves to suspend the bulbs 

 from the fetlock, it has been 

 termed the suspensory ligament 

 of the bulbs (figs. 31, 5, and 

 33, c). 



Similar, but smaller liga- 

 ments arise from the bulbs, and 

 become attached to the posterior 

 border of the lateral cartilage 

 (fig. 31, b^). At the same point 

 is inserted a tendon, originating 

 in the skin close to the horny 

 skin under the fetlock (fig. 31, d). 



Fig. 31. — Infero-posterior view of right fore-foot, showinij the position of the plantar cushion. 

 The outer lateral cartilage and the tissues covering the lower surface uf the pedal bone 

 (sensitive frog and sensitive sole) have been removed, a, plantar cushion ; a', bulbar 

 portion of plantar cushion; a", cleft of the frog in which rests the "frog stay"; 

 b, origin of the so-called "suspensory ligament of the bulbs"; b', small elastic band 

 passing towards the lateral cartilage ; c, elastic band arising from lateral cartilage and 

 becoming inserted into pastern bone ; it unites with b ; d, small tendon whicli arises 

 from the skin and becomes attached, in common with b and c, to tht- pastern bone ; 

 «, fibro-elastic supporting sheath of flexor p. perforans ; /, flbro-elastic supporting sheath 

 of flexor ped. perforatus ; g, tlexor p. perforatus tendon ; h, flexor p. perforans tendon ; 

 i, suspensory ligament ; k, lower surface of pedal bone, to which the flexor p. perforans 

 tendon is attached. 



