g Pott's disease. There is
marked kyphosis at the seat of the disease and compensatory lordosis
above and below.

(Museum of the Royal College of Surgeons, Edinburgh.)]

[Illustration: FIG. 212.--Radiogram of Museum Specimen of Pott's
disease in a Child; the disease is located at the thoracico-lumbar
junction.

(Dr. Hope Fowler.)]

In rare cases the disease affects only the articular or the spinous
processes, producing superficial caries and a localised abscess.

#Clinical Features.#--The clinical features of Pott's disease vary so
widely in different regions of the spine, that it is necessary to
consider each region separately. To avoid repetition, however, certain
general features may be first described.

_Pain._--In the earliest stages, the patient complains of a feeling of
tiredness, which prevents him walking far or standing for any length
of time. Later, there is a constant, dull, gnawing pain in the back,
increased by any form of movement, particularly such as involves
jarring or bending of the spine. If the patient is a child, it is
noticed that he ceases to play with his companions, and inclines to
sit or lie about, usually assuming some attitude which tends to take
the weight off the affected segment of the spine (Figs. 214, 217). If
he is going about, the pain increases as the day goes on, but may pass
off during the night. It is often referred along the course of the
nerves emerging between the diseased vertebrae, and takes the form of
headache, neuralgic pains in the arms or side, girdle-pain, or
belly-ache, according to the seat of the lesion. Tenderness may be
elicited on pressing over the spinous or transverse processes of the
diseased vertebrae, or on making pressure in the long axis of the
spine. These tests, however, are not of great diagnostic value, and
they should be omitted, as they cause unnecessary suffering. It is to
be borne in mind that in some cases the disease is not attended with
any pain.

_Rigidity._--The pain produced by movement of the diseased portion of
the spine causes reflex contraction of the muscles passing over it,
and the affected segment of the column is thus rendered rigid. If the
palm of the hand is placed over the painful area while the patient
attempts to make movements of stooping, nodding, or turning to the
side, it is found that the vertebrae implicated move _en bloc_ instead
of gliding on one another. This rigidity of the diseased portion of
the column with "