ated
externally; or to the petrous temporal, from suppuration in the middle
ear.

The most common is an osteomyelitis commencing in the marrow exposed in
a wound infected with pyogenic organisms. In amputation stumps,
fungating granulations protrude from the sawn end of the bone, and if
necrosis takes place, the sequestrum is annular, affecting the
cross-section of the bone at the saw-line; or tubular, extending up the
shaft, and tapering off above. The periosteum is more easily detached,
is thicker than normal, and is actively engaged in forming bone. In the
macerated specimen, the new bone presents a characteristic coral-like
appearance, and may be perforated by cloacae (Fig. 122).

[Illustration: FIG. 122.--Tubular Sequestrum resulting from Septic
Osteomyelitis in Amputation Stump.]

Like other pyogenic infections, it may terminate in pyaemia, as a result
of septic phlebitis in the marrow.

The _clinical features_ of osteomyelitis in _an amputation stump_ are
those of ordinary pyogenic infection; the involvement of the bone may be
suspected from the clinical course, the absence of improvement from
measures directed towards overcoming the sepsis in the soft parts, and
the persistence of suppuration in spite of free drainage, but it is not
recognised unless the bone is exposed by opening up the stump or the
changes in the bone are shown by the X-rays. The first change is due to
the deposit of new bone on the periosteal surface; later, there is the
shadow of the sequestrum.

Healing does not take place until the sequestrum is extruded or removed
by operation.

_In compound fractures_, if a fragment dies and forms a sequestrum, it
is apt to be walled in by new bone; the sinuses continue to discharge
until the sequestrum is removed. Even after healing has taken place,
relapse is liable to occur, especially in gun-shot injuries. Months or
years afterwards, the bone may become painful and tender. The symptoms
may subside under rest and elevation of the limb and the application of
a compress, or an abscess forms and bursts with comparatively little
suffering. The contents may be clear yellow serum or watery pus;
sometimes a small spicule of bone is discharged. Valuable information,
both for diagnosis and treatment, is afforded by skiagrams.

[Illustration: FIG. 123.--New Periosteal Bone on surface of Femur from
Amputation Stump. Osteomyelitis supervened on the amputation, and
resulted in necrosis at the sawn section