On Motion in the lumbar division of the spine of birds, by George Oakley Fleming

                                so placed to form the articulation that the long diam-
eters of the semilunar cavities are reversed and they 
are so exactly adapted to each other as to form a most 
perfect 

Carus observes, “The vertebral column of Birds so far 
resembles that of tortoises, that only the caudal and more particularly 
the numerous cervical vertebrae have true articulations admitting of 
motion. The dorsal and sacral vertebrae on the contrary, even when 
they are not consolidated are connected by strong ligaments so as 
to form an inflexible column (In the Ostrich and cassowary alone the 
dorsal vertebrae are moveable). This dosposition on the one hand by the 
solidity it affords to the trunk facilitates the flight of the bird and on 
the other by the length and flexibility of the neck in some degree 
compensates for the incapability of the anterior extremities for seizing 
and feeling objects. Of the dorsal vertebrae the two first which support 
the false ribs (though there is sometimes only one of them) are 
somewhat moveable, and have a general resemblance to the cervical 
vertebrae.”
The muscles of the back are not mentioned by Carus. 
An Introduction to the Comparative Anatomy of Animals &c. 
translated by R. T. Gore. Vol. 1. p. 165. 
Dr Grant observes, “The muscles of the back are feeble and 
that part consequently admits of little motion, the straight, oblique, and 
transverse muscles of the abdomen are also very feeble and short in 
this class, that cavity being chiefly supported and covered by the sternum.” 
Lancet, June 13th 1834. 
Dr Roget, in speaking of the cervical vertebrae and of the 
contrivance for preventing pressure in this part, observes, - “The design of 
this structure is farther evident from its not existing in the dorsal 
and