CHAPTER III. 



Special Anatomy. — Necessity of Technical Terms. — The Ilio spinalis. — Defi- 

 nition OF Terms — Psoas magnus. — Iliacus. — Tensor VagiN;E Femoris. — Sar- 

 TORius. — Pectineus, Small Adductor, etc. — Great Gluteus. — Deep Gluteus. 



— Long Vastus. — Semi-tendinosus. — Semi-membranosus. — Great Adductor. — 

 Gracilis. — The Adduction and Abduction of Muscles. — Triceps Femoris. — 

 Gastrocnemii. — Automatic Action in the Hind Leg. — The Perforans and 

 Perforatus Muscles and their Tendons. — Suspensory Liga.ment. — Difficul- 

 ties i.N THE Way of determining the Amount of Work done by Muscles. — 

 Elongation and Contraction of the Limbs. — Interference and Stifle Action. 



— The Action of the Hock Joint to prevent Interference. — The Order of 

 Action in the Various Muscles of the Posterior Extremity in Locomotion. 



From the general observations of the last chapter we will proceed 

 to a consideration of the special anatomy, and analyze the locomo- 

 tive organs of the horse ; without this preparatory study it will be 

 impossible for any one to analyze its movements. 



Those who have studied and suppose they understand this action 

 must study again. Let no one be turned from this subject by tech- 

 nical terms ; they are indispensable in order to make one's self under- 

 stood by those who have already made a study of anatomy, as well 

 as to those who would follow the movements by wliich the various 

 paces are performed, and speak of a horse in more intelligible terms 

 than the slang of jockeys and the stables. I think I am warranted 

 in the belief that we are on a new era in the history of our old 

 friend and fellow-traveller; the increasing interest that is felt in 

 America as well as Europe, and the impulse that is sure to be com- 

 municated by the wonderful revelations of the camera, justify me 

 in that opinion. I shall not follow the usual order of descriptive 

 anatomists. 



It has already been stated that it is not the purpose of this essay 

 to teach anatomy any further than is necessary to demonstrate the 



