left to himself, the patient tends to maintain the limb in the “sling position,” and resists movements in the direction of abduction and rotation.  In the treatment of this affection the arm should be maintained at a right angle to the body, the arm being rotated medially (Codman).  When pain does not prevent it, movements of the arm and massage are persevered with.  In neglected cases, when adhesions have formed and the shoulder is fixed, it may be necessary to break down the adhesions under an anaesthetic.

The bursa is also liable to infective conditions, such as acute rheumatism, gonorrhoea, suppuration, or tubercle.  In tuberculous disease a large fluctuating swelling may form and acquire the characters of a cold abscess (Fig. 115).

The bursa underneath the tendon of the subscapularis muscle when inflamed causes alteration in the attitude of the shoulder and impairment of its movements.

An adventitious bursa forms over the acromion process in porters and others who carry weights on the shoulder, and may be the seat of traumatic bursitis.

The bursa under the tendon of insertion of the biceps, when the seat of disease, is attended with pain and swelling about a finger’s breadth below the bend of the elbow; there is pain and difficulty in effecting the combined movement of flexion and supination, slight limitation of extension, and restriction of pronation.

In the lower extremity, a large number of normal and adventitious bursae are met with and may be the seat of bursitis.  That over the tuberosity of the ischium, when enlarged as a trade disease, is known as “weaver’s” or “tailor’s bottom.”  It may form a fluctuating swelling of great size, projecting on the buttock and extending down the thigh, and causing great inconvenience in sitting (Fig. 116).  It sometimes contains a number of loose bodies.

There are two bursae over the great trochanter, one superficial to, the other beneath the aponeurosis of the gluteus maximus; the latter is not infrequently infected by tuberculous disease that has spread from the trochanter.

The bursa between the psoas muscle and the capsule of the hip-joint may be the seat of tuberculous disease, and give rise to clinical features not unlike those of disease of the hip-joint.  The limb is flexed, abducted and rotated out; there is a swelling in the upper part of Scarpa’s triangle, but the movements are not restricted in directions which do not entail putting the ilio-psoas muscle on the stretch.

Cartilaginous and partly ossified loose bodies may accumulate in the ilio-psoas bursa and distend it, both in a downward direction towards the hip-joint, with which it communicates, and upwards, projecting towards the abdomen.

The bursa beneath the quadriceps extensor—­subcrural bursa—­usually communicates with the knee-joint and shares in its diseases.  When shut off from the joint it may suffer independently, and when distended with fluid forms a horse-shoe swelling above the patella.