THE ANATOMY OF THE HORSE 43 



upper thigh, one ending in a tendon at the. point of the 

 hock, the other extending from the hock as a tendon along 

 down the back of the leg to the fetlock bone. There are 

 many different muscles over the body that are intimately 

 related to the locomotion of the horse, the material injury 

 of any one of which would seriously affect the efficiency 

 of various others. 



The digestive system of the horse consists of the mouth, 

 tongue, teeth, pharynx, oesophagus or gullet, stomach, large 

 and small intestines, pancreas, liver and spleen. The food 

 is taken into the mouth and with the aid of the tongue and 

 teeth, is broken and mixed with saliva, a digestive fluid. 

 The food is swallowed, and passes across the pharynx, a 

 small sac, about six inches long, and enters the oesophagus, 

 a tube 50 to 60 inches long, through which it moves into 

 the stomach. In this latter organ the food is churned and 

 mixed with water and digestive agents, especially gastric 

 juice and hydrochloric acid, this latter being especially 

 found in the stomach. From the stomach the food moves 

 into the small intestine, to be further acted on by digestive 

 agents, notably pancreatic juice secreted by the pancreas, 

 and bile from the liver. The stomach of the horse is com- 

 paratively small, its capacity ranging from two to four 

 gallons. According to Sisson 6 the size, form and position 

 of the stomach are subject to considerable variation. The 

 small size of the stomach explains the necessity of giving 

 light rations during working hours, with the heavier feed- 

 ing just before the greatest period of rest, such as at night. 

 The small intestine is about 70 feet long, and has a capacity 

 of about twelve gallons. Here the most active and efficient 

 work of digestion and assimilation takes place. The large 

 intestine is about 25 feet long, and extends from the small 

 intestine to the anus, from which point the solid excrement 

 is passed from the body. The intestines occupy the rear 

 part of the abdominal cavity, underneath and back of the 

 ribs. The liver of the horse covers much of the right side 



6 Anatomy of the Domestic Animals. S. Sisson, Philadelphia, 1914, p. 417. 



