[Illustration:  FIG. 107.—­Subungual Exostosis growing from Distal Phalanx of Great Toe, showing Ulceration of Skin and Displacement of Nail.

a. Surface view. b. On section.]

Syphilitic affections of the nails assume various aspects.  A primary chancre at the edge of the nail may be mistaken for a whitlow, especially if it is attended with much pain.  Other forms of onychia occur during secondary syphilis simultaneously with the skin eruptions, and may prove obstinate and lead to shedding of the nails.  They also occur in inherited syphilis.  In addition to general treatment, an ointment containing 5 per cent. of oleate of mercury should be applied locally.

Ingrowing Toe-nail.—­This is more accurately described as an overgrowth of the soft tissues along the edge of the nail.  It is most frequently met with in the great toe in young adults with flat-foot whose feet perspire freely, who wear ill-fitting shoes, and who cut their toe-nails carelessly or tear them with their fingers.  Where the soft tissues are pressed against the edge of the nail, the skin gives way and there is the formation of exuberant granulations and of discharge which is sometimes foetid.  The affection is a painful one and may unfit the patient for work.  In mild cases the condition may be remedied by getting rid of contributing causes and by disinfecting the skin and nail; the nail is cut evenly, and the groove between it and the skin packed with an antiseptic dusting-powder, such as boracic acid.  In more severe cases it may be necessary to remove an ellipse of tissue consisting of the edge of the nail, together with the subjacent matrix and the redundant nail-fold.

Subungual exostosis is an osteoma growing from the terminal phalanx of the great toe (Fig. 107).  It raises the nail and may be accompanied by ulceration of the skin over the most prominent part of the growth.  The soft parts, including the nail, should be reflected towards the dorsum in the form of a flap, the base of the exostosis divided with the chisel, and the exostosis removed.

Malignant disease in relation to the nails is rare.  Squamous epithelioma and melanotic cancer are the forms met with.  Treatment consists in amputating the digit concerned, and in removing the associated lymph glands.

CHAPTER XVIII

THE MUSCLES, TENDONS, AND TENDON SHEATHS

INJURIES:  Contusion; Sprain; Rupture—­Hernia of
    muscle—­Dislocation of tendons—­Wounds—­Avulsion of tendon. 
    DISEASES OF MUSCLE AND OF TENDONS:  Atrophy; "Muscular
    rheumatism"—­Fibrositis; Contracture; Myositis;
    Calcification and Ossification; Tumours.  DISEASES OF TENDON
    SHEATHS:  Teno-synovitis.

INJURIES