Compound Scoliosis, Occasioned By The Presence Of Supers Numerary Lateral Halves Of Vertebras, which compensate each other. The spine of a woman, set. 46, a very old preparation in the Museum at Vienna, but unfortunately not made with care proportioned to its value.

The sacrum and coccyx are united into one bone, on the right side of which there are four sacral foramina, and five on the left; for the first sacral vertebra is higher on the left side than on the right, and, as is evident, from its left spinous and articular processes being double, it consists on that side of two lateral halves of vertebrae fused together. The fifth lumbar is developed on the right side to a sacral vertebra, and thus the height of the left half of the sacrum is level with the right.

The first lumbar vertebra, in the concavity of the lumbar curve on the left side, appears very depressed, being not more than eight lines in height, and is concave from above downwards; while on the right side it is convex, and more than two inches high, and has a horizontal groove filled with an ossified intervertebral body, which indicates that it is double on that side. On the left side there is but one half arch, on the right there are two; there is also a small supernumerary intervertebral foramen on the same side (the right), and a half spinous process which has no fellow.

1 Oesterr. Med. Jahrb. vol. xix.

This odd half spinous process alters the position of the bodies of the vertebrae, and more particularly of their spinous processes above and below, in such a manner, that the laminae, more or less displaced and overlapping, terminate in a row of unsymmetrical spines. Inferiorly, the derangement stops at the second lumbar vertebra; but above, it reaches to the eighth dorsal; the right half spines of the first and second lumbar vertebrae lie beneath those of the left side: but the right half spines of the twelfth, eleventh, tenth, ninth, and eighth dorsal, are placed above those of the left side; hence they either appear unsymmetrical, or here and there one of the right half spines comes in contact with the left one of the vertebra next above.

The left half of the seventh dorsal vertebra, on the convex side of the inferior dorsal curve, is very high; it is pretty distinctly marked with a horizontal fissure in the same way as the first lumbar vertebra, and has two half arches instead of one, just as the first lumbar has on its right side. The lower one, which is the thicker, unites with the single arch that exists on the right side, and both together form a complete spinous process; the upper one terminates in an odd spine. There is an intervertebral foramen between the double arches, which is rather smaller than the foramina adjoining it above and below. The sixth dorsal vertebra has an apparently odd arch on the right side, which is adapted to the supernumerary half spine of the seventh dorsal vertebra, while the left arch, as will presently appear, is shrunken and combined with the corresponding arch of the fifth.

Between the sixth and fifth dorsal vertebrae, on the right side (at the convexity of the upper dorsal curve), another, a fourth, half vertebra is intercalated, which has a half arch on the right side. Its spinous process unites with the combined left half spines of the fifth and sixth dorsal vertebrae.

The fifth dorsal has an arch, the left half of which (at the convexity of the upper dorsal curve) is increased in breadth by union with the left half arch of the sixth dorsal. It has but one transverse process, and it unites with the half arch of the intercalated half vertebra to form one very broad, flat, spinous process; while it forms another, and more slender one, with the corresponding right half arch of the fifth.

The half arches of the fourth dorsal vertebra lie one over the other, the left uniting with the slender spinous process of the fifth (fifth and sixth), whilst the right terminates in a half spine.

The third dorsal is tolerably well formed; but the right half arches of the second and first coalesce, and their single spinous process joins with that of the left half arch of the second, while the other half of the first terminates again in an odd spine.

According to this, therefore, there are in the dorsal, lumbar, and sacral parts of the column, four half vertebrae, with their half arches and processes, too many. They are so placed on the two sides as fully to compensate one another; for upon the duplication of the left half of the first sacral vertebra there follows duplication of the right half of the first lumbar: and then, as the left half of the seventh dorsal is double, there is half a vertebra interposed on the right side between the sixth and fifth dorsal. And with regard to the arches, - the half arches of the sixth and fifth dorsal coalesce on the left side, and those of the second and first dorsal on the right.

Lastly, as has been already pointed out, there result from the position of the abnormal half vertebrae the following curvatures of the whole column:

A. Curvature Of The Sacrum

Curvature Of The Sacrum, with the convexity towards the left, in consequence of duplication of the left half of the first sacral vertebra: the development of the fifth lumbar vertebra to a half right sacral compensates this curve.

B. Slight Curvature

Slight Curvature in the lumbar and lower dorsal regions, in consequence of duplication of the right half of the first lumbar vertebra: the convexity at this part is directed towards the right.

Y. Considerable Curvature

Considerable Curvature in the middle dorsal region produced by the left half of the seventh dorsal vertebra being double: here the convexity is towards the left.

§. Considerable curvature in the upper dorsal region, which is caused by the half vertebra interposed between the sixth and fifth dorsal vertebrae: the convexity here faces the right. The last two form a very compressed S curvature; and the vertebrae are twisted upon their axes, and project backwards (kyphosis).

Corresponding to the anomalies in the vertebral column, there are some very remarkable peculiarities in the number, form, and attachment of the ribs. As there are two supernumerary half vertebrae in the dorsal region, one on the right side, and the other on the left, that is, one supernumerary dorsal vertebra, and the number of articulating surfaces on the bodies and transverse processes being in accordance with that number of vertebrae, there should be thirteen ribs on each side: but there is another attached to the seventh cervical vertebra, and there are actually fourteen more or less complete ribs on each side.

The first rib on the left side is attached by two heads, the upper one of which articulates with the seventh cervical vertebra just above its lower border, and the lower with the first dorsal: the two heads unite in a single neck; the tubercle divides, and is applied to the transverse processes of the seventh cervical and first dorsal vertebrae; and the rib then ends in a single shaft. The first rib on the right side is also attached by two heads: the upper, which is the thicker, and has a cloven neck, joins the seventh cervical vertebra opposite the upper head of its fellow; the lower head is more slender, but sinks deeper into an excavated articulating fossa between the first and second dorsal vertebrae. The three necks soon unite into a single broad one, which is attached by one tubercle to the transverse process of the seventh cervical vertebra, and by two others to a very large articular process on the coalesced right half arches of the first and second dorsal vertebrae; it then separates into two distinct shafts.

The third and fourth, or rather, if we enumerate by the heads of the ribs, the fourth and fifth, ribs on the left side have but one neck, and for a short distance also, only a single body. At the single very thick transverse process of the united left half arches of the fifth and sixth dorsal vertebrae, two ribs are attached, namely the sixth and seventh.

Moreover, anchylosis has taken place between the odd half arches and bones next adjoining them, between several of the bodies of the vertebrae, especially in the concavity of the curvatures, and also between the second and third cervical vertebrae.