, and is constricted opposite the annular ligament.

The onset and progress of the affection are most insidious, and the
condition may remain stationary for long periods. It is aggravated by
use or strain of the tendons involved. In exceptional cases the skin is
thinned and gives way, resulting in the formation of a sinus.

_Treatment._--In the common flexor sheath of the palm, an attempt may be
made to cure the condition by removing the contents through a small
incision and filling the cavity with iodoform glycerine, followed by the
use of Bier's bandage. If this fails, the distended sheath is laid open,
the contents removed, the wall scraped, and the wound closed.

A less common form of tuberculous disease is that in which the sheath
becomes the seat of _a diffuse tuberculous thickening_, not unlike the
white swelling met with in joints, and with a similar tendency to
caseation. A painless swelling of an elastic character forms in relation
to the tendon sheath. It is hour-glass-shaped in the common flexor
sheath of the palm, elongated or sausage-shaped in the extensors of the
wrist and in the tendons at the ankle. The tuberculous granulation
tissue is liable to break down and lead to the formation of a cold
abscess and sinuses, and in our experience is often associated with
disease in an adjacent bone or joint. In the peronei tendons, for
example, it may result from disease of the fibula or of the ankle-joint.

When conservative measures fail, excision of the affected sheath should
be performed; the whole of the diseased area being exposed by free
incision of the overlying soft parts, the sheath is carefully isolated
from the surrounding tissues and is cut across above and below. Any
tuberculous tissue on the tendon itself is removed with a sharp spoon.
Associated bone or joint lesions are dealt with at the same time. In the
after-treatment the functions of the tendons must be preserved by
voluntary and passive movements.

#Syphilitic Affections of Tendon Sheaths.#--These closely resemble the
syphilitic affections of the synovial membrane of joints. During the
secondary period the lesion usually consists in effusion into the
sheath; gummata are met with during the tertiary period.

Arborescent lipoma has been found in the sheaths of tendons about the
wrist and ankle, sometimes in a multiple and symmetrical form,
unattended by symptoms and disappearing under anti-syphilitic treatment.

#Tumours of Tendon Sheaths.