History.—­To English veterinarians appears to belong the credit of discovering navicular disease.  As early as 1752 we find one, Jeremiah Bridges, in ‘No Foot, No Horse,’ drawing attention to ’coffin-joint lameness,’ and advocating for its treatment setoning of the frog.  It appears, too, that Moorcroft, prior to his departure for India in 1808, was acquainted with what was then known as coffin-joint[A] lameness, having drawn attention to it in 1804 in a letter to Sir Edward Codrington.[B] In 1819 Moorcroft made it even plainer still that he was fully acquainted with what we now know as navicular disease.  This we learn from a letter written by him to Sewell, in which he laid claim to being the originator of neurectomy.  In this letter he says: 

[Footnote A:  The coffin-joint at this time included the navicular bursa.]

[Footnote B:  Percival’s ‘Hippopathology,’ vol. iv., p. 132.]

’On dissecting feet affected with these lamenesses, the flexor tendon was now and then observed to have been broken, partially or entirely, but more commonly to have been bruised and inflamed in its course under the navicular or shuttle bone, or at its insertion into the bone of the foot.  Sometimes, although seldom, the navicular bone itself has been found to have been fractured; at others its surface has been deprived of its usual coating, and studded with projecting points or ridges of new growth, or exhibiting superficial excavations more or less extensive.’[A]

[Footnote A:  Ibid.]

Pathology and Point of Commencement of the Disease.—­The exact position in which the diseased process starts has for a long time been a subject of discussion, and even now it is doubtful whether the point has been definitely settled.  To mention but a few among many:  We find Mr. Broad, of Bath, strenuously insisting on the fact that the disease commences in the interior of the navicular bone.  Just as strenuously we find the editor of the journal in which the matter is being discussed, the late Mr. Fleming, asserting that the disease commences in the bursa.[A] Others, too, hold that the disease commences primarily in the tendon.  Wedded to this view was the discoverer, Mr. Turner, of Croydon; while Percival commits himself to the statement that it is either the central ridge or the postero-inferior surface of the navicular bone, or the opposed concavity in the perforans tendon, that shows the earliest signs of the disease.  The observations made by Dr. Brauell, the first Continental writer to fully describe the disease, led him to the statement that neither the bone nor the bursa was the invariable starting-point of the trouble, but that usually it commenced in inflammation of the bursa itself.

[Footnote A:  Percival’s ‘Hippopathology,’ vol. iv., p. 132.]

Without, therefore, committing ourselves to an expression of opinion as to the precise starting-point of the affection, we shall describe the pathological changes occurring in navicular disease as noted in (1) the bursa, (2) the cartilage, (3) the tendon, and (4) the bone.