Occurrence and Method of Examination.—­This condition, then, is a rather common cause of lameness and in no case, where cause of the claudication is not obvious, is the practitioner warranted in concluding his examination without careful search for the possible existence of nail puncture of the solar surface of the foot.

[Illustration:  Fig. 39—­Skiagraph of foot.  The X-ray offers very limited possibilities in the diagnosis of lameness.  The location of a “gravel” or a nail that had worked its way some distance from the surface, or of an abscess of some proportion, deep in the tissues, might be facilitated under some circumstances by the aid of the X-ray.  Its use in the detention of fractures is very limited, owing to the difficulty encountered in getting a view from the right position—­many trials being necessary in most cases.  The case shown above was diagnosed clinically as incipient ringbone.  The X-ray revealed no lesions. (Photo by L. Griessmann.)]

In occasional instances there co-exists an obvious cause for supporting-leg-lameness and an occult cause—­a nail puncture.  Where such complications are met, the practitioner is not necessarily guilty of neglect or carelessness when the nail puncture is not discovered at once, nevertheless, an examination is not complete until practically every possible cause of lameness has been located or excluded in any given case.

In a search for nail puncture it is necessary to expose to view every portion of the sole and frog in such manner that the existence of the smallest possible wound will be revealed.  This necessitates removal of the shoe, if, after a preliminary examination, a puncture is not found, when there is good reason to suspect its presence.  However, where it is readily possible to locate and care for a wound without removal of the shoe, allowing the shoe to remain materially facilitates retaining dressings in position and relieves the solar surface of contact with the ground.  If extensive injury or infection exists, it is of course necessary to remove the shoe and leave it off.  By removing a superficial portion of all of the sole and frog, thus carefully and completely exposing to view all parts of the solar surface of the foot, and with the aid of hoof-testers one is enabled to positively determine the existence of nail punctures.  Because of the tendency of puncture wounds of the foot to close, and since the superficial portion of the solar structures are usually soiled, it is absolutely necessary to conduct examinations of this kind in a thorough manner.

Symtomatology.—­Not all cases of nail puncture cause lameness during the course of the disturbance and in many instances no lameness is manifested for some time after the injury has been inflicted—­not until infection has been the means of causing considerable inflammation of sensitive structures.  Nevertheless, this lack of manifestation occurs only in cases where serious injury has not taken place and the degree of lameness is a constant and reliable indicator of the character and extent of nail punctures within twenty-four hours after injury has been inflicted.