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.#—­Innocent tumours, such as lipoma, fibroma, and myxoma, are rare.  Special mention should be made of the myeloma which is met with at the wrist or ankle as an elongated swelling of slow development, or over the phalanx of a finger as a small rounded swelling.  The tumour tissue, when exposed by dissection, is of a chocolate or chamois-yellow colour, and consists almost entirely of giant cells.  The treatment consists in dissecting the tumour tissue off the tendons, and this is usually successful in bringing about a permanent cure.

All varieties of sarcoma are met with, but their origin from tendon sheaths is not associated with special features.

CHAPTER XIX

THE BURSAE

Anatomy—­Normal and adventitious bursae—­Injuries:  Bursal
    haematoma—­DISEASES:  Infective bursitis; Traumatic or trade
    bursitis; Bursal hydrops; Solid bursal tumour; Gonorrhoeal and
    suppurative forms of bursitis; Tuberculous and syphilitic
    disease—­Tumours—­Diseases of individual bursae in the upper and
    lower extremities.

A bursa is a closed sac lined by endothelium and containing synovia.  Some are normally present—­for instance, that between the skin and the patella, and that between the aponeurosis of the gluteus maximus and the great trochanter. Adventitious bursae are developed as a result of abnormal pressure—­for example, over the tarsal bones in cases of club-foot.

#Injuries of Bursae.#—­As a result of contusion, especially in bleeders, haemorrhage may occur into the cavity of a bursa and give rise to a bursal haematoma.  Such a haematoma may mask a fracture of the bone beneath—­for example, fracture of the olecranon.

#Diseases of Bursae.#—­The lining membrane of bursae resembles that of joints and tendon sheaths, and is liable to the same forms of disease.