LOCOMOTION. 



621 



It will not be forgotten that in joiats the insheathing carti- 

 lages (sometimes others more or less free), the synovial fluid, 

 etc., all tend to diminish friction and lessen 

 Concussion. 



We shall now describe the principal gaits 

 of the horse in a somewhat synoptical way. 

 In each gait we have to consider the 

 relative position of the four limbs, the 

 duration of each phase in the move- 

 ment, the length of the stride, its 

 rate, etc. Much that applies to 

 the horse holds good, of course, 

 of other quadrupeds. 



In every gait each leg passes 

 from a condition of flexion to 

 one of extension, the degree be- 

 ing dependent on the speed or, 

 more correctly, the effort of the 

 animal to attain high speed or 

 the reverse. When the foot 

 rests upon the 

 ground before 

 the limb is re- 

 moved, it de- 

 scribes the arc 

 of a circle, or os- 

 cillates like a 

 pendulum so that 

 the fl.exors and 

 extensors are 

 used alternately 

 ^-^ more and less; 

 ^5: though in all 

 movements it is 

 likely that nei- 

 . , 20, 



23, large meta^ 



24, suspensory relaxed. The 



Fie. 470.— Internal aspect of left an 

 terior limb (Chauveau). 1, pro- 

 longing cartilage of scapula ; 2, 

 inner snrface or scapula; 3, Bub- 

 scapularis; 4, adductor of fore- 

 ann, or portion of caput mag- 

 num; 7, large extensor of fore- 

 arm, other portion of caput mag- 

 num; 8, middle extensor, or ca- 

 put medium; 9, humeralis exter- 

 nus, or short flexor of forearm; 

 10, coraco-humeralis; 11, upper 

 extremity of humerus ; 12, co- 

 raco-radialis, or flexor brachii ; 



13, lower extremity of humerus; 



14, brachial fascia ; 15, anterior 

 extensor of metacarpus, or ex- 

 tensor metacarpi magnus ; 16, 

 belly and aponeurotic termina- 

 tion of flexor brachii; 17, ulna; 

 18, ulnaris accessorius, or oblique 

 flexor of metacarpus; 19,, inter- 

 nal flexor of metacamus, or epicondylo-metacarpus; 20, ihpv <spt iss wlinllT!- 

 radius; 21. tendon of oblique extensor: 22. lar/e metal ''"''^ ''*"' "" wnouy 

 carpal-bone : 23, flexor tendons of foot ; . , 



ligament ; 25, internal rudimentary metacarpal bone; 26. ,i i, 



extensor tendon of foot; 27, metacarpo - phalangeal more tnorougnly 

 sheath; 28, lateral cartilages of foot; 29, podophyllae. Tnusriilfir mnvp 



ments are studied the more complex, so far as the use of muscles 

 is concerned, are they found to be, a fact which is illustrated 

 when even a single muscle is weakened or paralyzed. 



