In the septum of the nose, the nasal bones, and the hard palate, gummatous disease causes ulceration, which, beginning in the mucous membrane, spreads to the bones, and being complicated with septic infection leads to caries and necrosis.  In the nose, the disease is attended with stinking discharge (ozoena), the extrusion of portions of dead bone, and subsequently with deformity characterised by loss of the bridge of the nose; in the palate, it is common to have a perforation, so that the air escapes through the nose in speaking, giving to the voice a characteristic nasal tone.

Syphilitic disease of the tibia may be taken as the type of the affection as it occurs in the long bones.  Gummatous disease in the periosteum may be localised and result in the formation of a well-defined node, or the whole shaft may become the seat of an irregular nodular enlargement (Fig. 132).  If the bone is macerated, it is found to be heavier and bulkier than normal; there is diffuse sclerosis with obliteration of the medullary canal, and the surface is uneven from heaping up of new bone—­hyperostosis (Fig. 131).  If a periosteal gumma breaks down and invades the skin, a syphilitic ulcer is formed with carious bone at the bottom.  A central gumma may eat away the surrounding bone to such an extent that the shaft undergoes pathological fracture.  In the rare cases in which it attacks the articular end of a long bone, gummatous disease may implicate the adjacent joint and give rise to syphilitic arthritis.

[Illustration:  FIG. 131.—­Syphilitic Hyperostosis and Sclerosis of Tibia, on section and on surface view.]

Clinical Features.—­There is severe boring pain—­as if a gimlet were being driven into the bone.  It is worst at night, preventing sleep, and has been ascribed to compression of the nerves in the narrowed Haversian canals.

The periosteal gumma appears as a smooth, circumscribed swelling which is soft and elastic in the centre and firm at the margins, and shades off into the surrounding bone.  The gumma may be completely absorbed or it may give place to a hard node.  In some cases the gumma softens in the centre, the skin becomes adherent, thin, and red, and finally gives way.  The opening in the skin persists as a sinus, or develops into a typical ulcer with irregular, crescentic margins; in either case a probe reveals the presence of carious bone or of a sequestrum.  The health may be impaired as a result of mixed infection, and the absorption of toxins and waxy degeneration in the viscera may ultimately be induced.

A central gumma in a long bone may not reveal its presence until it erupts through the shell and reaches the periosteal surface or invades an adjacent joint.  Sometimes the first manifestation is a fracture of the bone produced by slight violence.

In radiograms the appearance of syphilitic bones is usually characteristic.  When there is hyperostosis and sclerosis, the shaft appears denser and broader than normal, and the contour is uneven or wavy.  When there is a central gumma, the shadow is interrupted by a rounded clear area, like that of a chondroma or myeloma, but there is sclerosis round about.