DISEASES OF THE FETLOCK, ANKLE, AND FOOT. 427 



their depth, involve the plantar cushion, the plantar aponeurosis, 

 the sesamoid sheath, the navicular bone, or the coffin joint. 



Punctured wounds are more liable to be deep in flat or convex feet 

 than in well-made feet, and as a rule, recovery is neither so rapid nor 

 feo certain. These wounds are less serious in animals used for heavy 

 draft than in those required to do faster work ; for the former may be 

 useful, even if complete recovery is not effected. Lastly, punctured 

 wounds of the fore feet are more serious than of the hind feet, for the 

 reason that in the former the instrument is liable to enter the foot in 

 a nearly perpendicular line, and, consequently, is more liable to 

 injure the deeper structures of the foot ; in the hind foot, the injury 

 is generally near the heels and the wound oblique and less deep, 



Sym'pt07(is. — A nail or other sharp instrument may penetrate the 

 frog and remain for several days without causing lameness; in fact, 

 in many cases of punctured wound of the frog the first evidence of 

 the injury is the finding of the nail or the appearance of an opening 

 where the skin and frog unite, from which more or less pus escapes. 

 Even when the sole is perforated, if the injury is not too deep, no 

 lameness develops until suppuration is estiiblished. In all cases of 

 foot lameness, especially if the cause is obscure, the foot should be 

 examined for evidence of, injury. 



The lameness from punctured wounds, accompanied with suppu- 

 ration, is generally severe, the patient often refusing to use the 

 affected member at all. The pain being lancinating in character, 

 he stands with the injured foot at rest or constantly moves it back 

 and forth. In other cases the patient lies down most of the time 

 with the feet outstretched; the breathing is rapid, the pulse fast, the 

 temperature elevated, and the body covered with patches of sweat. 



When the plantar aponeurosis is injured, the pus escapes with diffi- 

 culty and the wound shows no signs of healing; the whole foot is 

 hot and very painful. If the puncture involves the sesamoid sheath, 

 the synovial fluid escapes. At first this fluid is pure, like joint water, 

 but later becomes mixed with the products of suppuration and 

 loses its clear, amber color. Suppuration generally extends up the 

 course of the flexor tendon, an abscess forms in the hollow of the 

 heel, and finally opens somewhere below the fetlock joint. The 

 whole coronet is more or less swollen, the discharge is profuse and 

 often mixed with blood, yet the suffering is greatly relieved from 

 the moment the abscess opens. 



If the puncture reaches the navicular bone the lameness is intense 

 from the beginning; but the only certain way to determine the 

 existence of this complication is by the use of the probe ; and unless 

 there is a free escape of synovia it must be used with the greatest 

 of care, else the coffin joint may be opened. 



