The fistula may be present at birth, or may result from the rupture of a cystic swelling, which has become infected. Clear viscous fluid exudes from it, and, when the fistula is complete and the lumen sufficiently wide, particles of food may escape. As the track is tortuous, it is seldom possible to pass a probe along it, but its extent and course may be recognised by injecting an emulsion of bismuth and taking an X-ray photograph.
The treatment consists in excising the fistula in its whole length, but, owing to its long and tortuous course, and its relations to important structures, the operation is a tedious and difficult one. Less radical measures, such as scraping with the sharp spoon, cauterising, or packing, are seldom successful.
Cervical Ribs.—Supernumerary ribs are not infrequently met with in connection with the seventh cervical vertebra, and in the majority of cases the condition is bilateral. The extra rib may be thin and pointed, and project straight out from the transverse process terminating in a free end, in which case, as it passes above the subclavian artery and the brachial plexus, it gives rise to no trouble. In other cases it arches downwards and forwards, and is attached by dense fibrous tissue to the first thoracic rib about the level of the scalene tubercle, or to the sternum by cartilage like an ordinary rib. When it encroaches upon the posterior triangle the scalene muscles are attached to it, and the subclavian artery and the lower trunk and medial cord of the brachial plexus pass over it in a groove behind the scalenus anterior. The pleura may reach as high as the medial border of the rib.
Clinical Features.—The condition, which is more common in women than in men, is seldom recognised before the age of twenty, and is often discovered accidentally, for example after some emaciating illness, or by a tight collar causing pain. The diagnosis is established by the X-rays.
Fig. 269.—Bilateral Cervical Ribs; the left one is the better developed.
When symptoms arise, they may be referable either to pressure on the artery or on the nerve roots. When the subclavian artery is displaced upwards it may be recognisable as a prominent pulsatile swelling, and as the part of the vessel distal to the rib is sometimes dilated and yields a systolic bruit, it may simulate an aneurysm (Sir William Turner). The pulse beyond is weakened while the arm hangs by the side, but may be restored by raising the hand above the head. Gangrene of the tips of the fingers has been observed in rare instances, but it is probably nervous rather than vascular in origin.
Symptoms referable to pressure on the nerve roots usually affect the right arm, and may be either neuralgic or paralytic in character (Wm. Thorburn). In the neuralgic group there is tingling pain, a feeling of numbness, and sensations of cold in the limb, most marked along the ulnar border of the forearm; the arm is weak, and susceptible to cold. This condition may be mistaken for brachial neuritis; it is relieved, however, by holding the arm above the head, for example, during sleep.
In the paralytic group, the pressure symptoms are referred to the first dorsal, or first dorsal and eighth cervical roots. The paralysis is most marked in the muscles of the thumb, and becomes less towards the ulnar side; the affected muscles atrophy, especially those forming the thenar eminence, and the finer movements of the thumb and fingers are impaired.