n as the _scoliotic pelvis_.

[Illustration: FIG. 228.--Scoliosis with primary curve in Thoracic
Region.]

In spite of the marked deformity the spinal cord is never compressed.

_Clinical features._--The development of scoliosis is always slow and
insidious. As a rule, attention is first attracted to the deformity
about the age of puberty, but in most cases it has existed for a
considerable time before it is observed. The patient--usually a girl,
although it also occurs in boys--is easily fatigued, has difficulty in
keeping herself erect, and often complains of pain in the back and
shoulders and along the intercostal spaces on the side of the
convexity. To relieve the muscles of the back she is inclined to
lounge in easy and ungainly attitudes.

The most common form of scoliosis met with in adolescents is a
_primary thoracic curvature_ with its convexity to the right (Fig.
227), and with more or less marked compensatory curves towards the
left in the lumbar and cervical regions. The thoracic spines lie
towards the right of the middle line. On account of the prominence of
the ribs, the right scapula is projected backwards, and its inferior
angle is on a higher level and farther from the middle line than that
of the left scapula. The right shoulder seems higher than the left,
and is popularly said to be "growing out"--a point which is often
first observed by the dressmaker. The right side of the back is unduly
prominent, while the left side is flattened. A deep sulcus forms in
the left flank below the costal margin, and the space between the arm
and the chest wall--the "brachio-thoracic triangle"--on the left side
is much more marked than on the right; and the left iliac crest
usually projects upwards and backwards. As seen from the front, the
right side of the chest is flattened, while the left side is
abnormally prominent, the breasts are asymmetrical, and the right
nipple is on a higher level than the left.

[Illustration: FIG. 229.--Scoliosis showing rotation of bodies of
vertebrae, and widening of intercostal spaces on side of convexity.]

In aggravated cases, the patient may suffer from shortness of breath
on exertion, and the respiratory difficulty may react on the heart,
causing dilatation of the right side, palpitation, and precordial
pain.

Sometimes, and particularly in males, the primary curvature is in the
lumbar region, and the convexity is to the left. The deviation of the
lumbar vertebrae produces