NUMERICAL VARIATION IN THE HUMAN SPINE. 



301 



stern o-cla\'icular joint is lower and more oblique on the left. The subclavian artery 

 evidently passed over the rudimentary 1st rib. 



Except that the sides are reversed, this is exceedingly like the state of affairs in spine 

 202, only there we have a small pair of cervical riljs, and here a small pair of 1st thoracic 

 ribs. 



572. — Male, white, aet. 70. The specimen consists of the right half of the sternum, 

 and of the right 1 st rilj, which is small and continued by ligament to a calcification of the 

 cartilasj-e near the manubrium. The distance from the end of the bone to the sternum is 

 about 3 cm. There were six lumbar verteljrae. 



Fusion of First and Second Thoracic Ribs. 



C-1. Cat. 9379-49. — Tliis specimen consists of the cervical and upper part of the 

 thoracic regions and of the right half of 

 the upper part of the sternum. The 

 spine was normal. The only peculiarity 

 worth noting is presented by the first 

 two ribs of the right side. The heads of 

 both ribs rest entirely- against the 1st 

 thoracic vertebra, not encroachiirg on 

 the disc either above or below it. The 

 head of the 2d rib is much smaller than 

 normal. There is but a slight interval 

 between the two heads. The tubercle 

 of the 2d rib also is very small and rests 

 on a minute facet at the very upper 

 corner of the end of the corresponding 

 transverse process. At about 4 cm. 

 from their origin the two ribs fuse into 

 a broad plate, on which all marks of 

 separation are gradually lost. A rudi- 

 mentary scalene tubercle on its upper 

 edge separates two slight grooves. The C_i. 



greatest breadth of the plate, 4.2 cm., is 



just before it divides into a short upper and a longer lower pi-olongation representing the 

 terminations of the shafts of the ribs. Each is continued by a piece of cartilage to its 

 normal termination. 



