[Illustration:  FIG. 141.—­EXCISION OF THE LATERAL CARTILAGE. (AFTER BAYER.) The horny wall is stripped off over the seat of operation. a, Semicircular flap of sensitive laminae, coronary cushion, and skin; b, the lateral cartilage; c, the sensitive laminae; d, the coronary cushion.]

That this incision of the sensitive structures should be kept at 1/4 inch from the one in the horn has a reason.  It is that when this flap is again placed into position (as later it will have to be) we have round its circumference a rim of soft structures into which to place the sutures.  And in this connection it is well to advise the operator that the thinness of the keratogenous membrane (the laminal portion of it) should warn him that the portion of it to be turned up—­namely, that forming the tip of the flap—­should be scraped away quite close to the os pedis.  Unless this is done, there will not be a sufficient thickness left to afterwards bring into position and suture.

The half-moon-shaped piece of tissue incised is now carefully dissected away from the external face of the cartilage, until it may be turned up as a flap (see Fig. 141, a), and held from off the cartilage by a tenaculum.

The exposed cartilage is now carefully removed by the aid of a sage-knife and a stout pair of forceps, the same precaution of holding the foot well forward being again taken in order to avoid wounding of the articular capsule.

At this stage in the operation considerable care is required.  The operator must remember that close beneath him, and more particularly in front, is the pedal articulation.  It is better, therefore, to excise the cartilage piecemeal, and to do it carefully, than to attempt, at the risk of injury to the joint, to make the operation ‘showy.’

During removal of the cartilage, the terminal branches of the digital arteries are wounded, as also are the veins of the coronary plexus.  Should either of these stand out with extra prominence from the others, it should be picked up with a pair of forceps, and ligatured with either carbolized gut or silk.

Attention should then be given to the flap of skin and coronary cushion.  Wherever a sinus has existed in it, it is to be carefully scraped, and all dead portions of tissue removed.  This done, the flap is allowed to fall into position, and is there carefully sutured, not only at the skin of the coronet, but along the whole circumference of the incision.

Dressing of the Wound and After-Treatment.—­The whole secret of the success of this operation is in afterwards maintaining a strict asepsis of the wound.  Unless there is reasonable room for belief that this may be done, the operation had far better not be advised, for if the wound is afterwards suffered to get into a suppurating and dirty condition, the last stage of the case may be worse than the first Synovitis and arthritis, with certain anchylosis of the joint, and a probable loss of our patient, is almost bound to follow.