NUMERICAL VARIATION IN THE HUMAN SPINE. 



251 



(Tlic two following cases of cer\acal ribs are 

 much alike. The last ribs, on the 19th vertebra, 

 though separate, much resemble transverse pro- 

 cesses. The thorax seems, therefore, to have 

 moved upwards.) 



729. Cat. 9379-32. 



Female, wliite, aet. 26. Vertebral formula 

 normal. (The sacrum has 5, and the coccyx 4.) 



The right cervical rib is small, consisting of 

 a head, neck, tubercle and a minute .shaft ending 

 free in a point. The length, following the ciuve. 

 is 3.2 cm. The left cervical rib is ().2 cm. lonu' 



and altogether 



It ends free in a knob to 



-&-"^-- larger, 

 which shreds of muscle were attached. Just be- 

 hind this is a smooth groove, no doubt for the 

 subclavian artery. It was connected to the first 

 thoracic rib by muscular fibres, having the direc- 

 tion of the external intercostal. There was no 

 internal layer. The pleural cavity extended up 

 to the cervical rib. The 1st thoracic ribs, espe- 

 cially the left, encroach somewhat on the body of 

 the 7th vertebra. The right one is tolerably nor- 

 uud. with two ill-marked grooves. The left one 

 is longer, narrower, and a good deal like a 2d rib. 

 It has a groove, presumably for the vein, just in 

 front of the end of the cer\dcal rib. Seen from 

 behind, the transverse processes of the 7th cervi- 

 cal are abnormally expanded. The proportions of 

 the body of this vertebra resemble those of a 1st 

 thoracic, antl the latter does not have the usual 

 .slight elevation of its superior lateral borders. 



The costal elements of the 19th vertebi'a 

 resemble closely lumbar transverse processes 

 which have been cut through some 5 mm. from 

 the base, so that the greater part is movable. 



729 



