lacuna of the frog, the two meeting at the frog’s point.  Each incision thus made should be carried deep enough to cut through the substance of the plantar cushion.  A tape is then passed through the point of the frog, tied in a loop, and given to an assistant to draw backwards.  The plantar cushion itself is then incised in a direction from before backwards, and pulled on by the assistant, so as to expose the plantar aponeurosis.

Should this be found at all necrotic, it may be taken that purulent inflammation of the navicular bursa and of the navicular bone itself exists.  The operator must then proceed to resection of the tendon in order to treat the deeper structures thus affected.  At its point of insertion into the semilunar crest the tendon is severed and afterwards reflected.  This exposes the inferior face of the navicular bone.  Instead of the glistening and clear appearance it ordinarily presents, its glenoid cartilage is found to be showing haemorrhagic or even purulent spots of necrosis.  The terminal portion of the tendon must then be excised.

To effect this a clean transverse incision is made at the extreme upper border of the navicular bone.  Here we are in close contact with the pedal articulation, and great care is necessary in making this last incision, in order that the synovial sac may not be penetrated.

All structures showing spots of necrosis should now be carefully removed, either with the knife or with the curette.  The knives most suitable for the last stages of this operation are those depicted in Fig. 45 (c, d, and e).  The curette, or Volkmann’s spoon, we show in Fig. 106.

[Illustration:  FIG. 107.—­RESECTION OF TERMINAL PORTION OF THE PERFORANS.  The horny sole and the horny frog stripped from off the sensitive structures. a, The plantar cushion; b, b, the plantar aponeurosis, or terminal portion of perforans; c, the navicular bone; d, interosseous ligaments of the pedal articulation; e, e, semilunar crest of the os pedis; f, inferior surface of os pedis; g, g, the sensitive laminae of the bars; h, h, bearing surface of the wall; i, i, the sensitive sole; k, the sensitive frog.]

When at all diseased the glenoidal surface of the navicular bone should be curetted, even to the extent of the removal of the whole of the cartilage.  A healthy, granulating surface is thus insured.

The above figure from Gutenacker’s ‘Hufkrankheiten’ explains shortly the position of the operation wound and the structures involved, rendering further description unnecessary here.

The operation ended, the dressing follows.  Upon this depends very largely the ultimate recovery of the patient, for it is only by careful attention and suitable dressings that effectual repair of the injured structures may be brought about.

A light shoe is first tacked on to the foot, and those portions of the horny sole that have been allowed to remain dressed with Venice turpentine, tar, or other thickly-adherent antiseptic.