of Pott's disease of fourth, fifth, and
sixth thoracic vertebrae.]

_Cord and Nerve Symptoms._--When the spinal cord is pressed upon, the
motor fibres are first affected as they lie superficially on the
antero-lateral aspects of the cord, and are more sensitive to
pressure. There is at first weakness or paresis of the muscles
supplied from the part of the cord below the seat of pressure. The
knee-jerks and plantar reflexes are exaggerated, and there is marked
ankle clonus. Later, there is paralysis of the spastic type, varying
in extent and sometimes amounting to complete paraplegia, and this may
come on gradually or quite suddenly. There is wasting of muscles from
disuse, and later a tendency to contracture and the development of
deformities, as a result of sclerosis or descending degeneration of
the cord.

The sensory fibres usually escape, although in some cases there is
partial anaesthesia and perversion of sensation. When there is also
myelitis, loss of sensibility to pain (analgesia) below the level of
the lesion is one of the most characteristic symptoms. In severe cases
there is incontinence of urine and of faeces, as the patient loses
control of the sphincters. Acute bed-sores are not uncommon.

The symptoms referable to pressure on the _nerve roots_ at their
points of emergence are pain and hyperaesthesia along the course of the
nerves that are pressed upon, and occasionally weakness and wasting of
the muscles supplied by them; girdle-pain is often a prominent symptom
in adults.

In the #diagnosis# of Pott's disease in young children, chief stress
is laid on the demonstration of rigidity of the affected portion of
spine; the child is laid prone and is lifted by the legs and feet so
as to hyper-extend the spine; in Pott's disease the spine is held
rigid, while in the rickety and other conditions that resemble it, the
movements are normal.

#Treatment of Pott's Disease.#--In addition to the general treatment
of tuberculosis, the essential factor consists in _immobilising
the spine in the recumbent posture and in the attitude of
hyper-extension_; this must be persisted in until the diseased
vertebrae become fused together or ankylosed by new bone, a result
which is estimated partly by the disappearance of all symptoms and
more accurately by observing the formation of the new bone in
successive skiagrams.

Under conservative measures it is estimated that this reparative
process entails an immobilisation