la only extends as high as the hyoid.

[Illustration: FIG. 268.--Congenital Branchial Cyst in a woman aet. 33.

(Microscopically the cyst was lined with squamous epithelium and the
wall contained rudimentary salivary-gland tissue.)]

The part of the tract near the tongue is lined by squamous
epithelium; the lower part by columnar epithelium, which, below the
level of the hyoid, is usually ciliated. Lymphoid tissue and mucous
glands are found in its wall.

The _treatment_ consists in excising the duct and the connections, and
it is usually necessary to resect the central portion of the hyoid
bone to ensure complete removal.

The _lateral fistula of the neck_--formerly described as a branchial
fistula--according to Weglowski, usually takes origin from the remains
of the hypoblastic diverticulum, which arises from the pharyngeal part
of the third visceral cleft and extends downwards to form the thymus
gland. The internal opening is situated in the lateral wall of the
pharynx in the region of the posterior palatine arch close to the
tonsil, and the fistula passes out above the hypoglossal nerve, and
runs downwards and laterally between the carotids and along the medial
border of the sterno-mastoid muscle. When the fistula is complete, the
external opening is situated a short distance above the
sterno-clavicular joint. As the lower part of the thymus canal most
often persists, an incomplete external fistula is the form most
frequently met with. It is lined with ciliated columnar epithelium.

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