VERTEBRAL COLUMN 129 



equal, then the transverse again becomes the greater. The first ver- 

 tebra resembles a cervical in having the ends of the body excavated, 

 the transverse processes longer, and the spinous process less inclined. 



The end of the transverse process is simple in the vertebrae 

 near the neck, irregular in the eleventh, and bifid in the twelfth 

 to form the mammillary and accessory processes. The tubercular 

 articular facets on the transverse processes are deepest on the 

 second vertebra and are absent on the eleventh and twelfth. 



A single costal facet is present on each side of the body of 

 the tenth and eleventh and on the side of the pedicle of the 

 twelfth vertebra, 



The eleventh vertebra is the anticlinal vertebra, because, 

 although none of the spinous processes have a cephalic inclination, 

 its process marks the point at which the remaining processes begin 

 to have a dorsal direction only. 



/ 



The caudal articular processes of the twelfth thoracic vertebra 

 face laterally rather than ventrally ; hence they are seen when the 

 vertebra is viewed from the side. 



HUMAN LUMBAR VERTEBRA. 



The five lumbar vertebra of man (Figs. 85, 90) differ very 

 much in appearance from the lumbar vertebras of the cat. Their 

 bodies are so greatly compressed that their 

 cephalo-caudal diameter is the smallest of FlG - 90 - 



the three. Their pedicles are not large 

 plates, but columns ; their laminsB are narrow 

 and enclose a triangular neural canal. The 

 transverse processes are narrow and project 



laterally and slightly dorsally ; those of the A LUMBAR VERTEBRA. 

 first and second vertebrae are the longest, 



i n *' centrum; 2, side of the arch; 3, 



tllOSe Of the fourth the mOSt pointed, While 4 - intervertebral notches; 5, spinous 



process; 6, transverse process; 7, 



tllOSe Of the fifth are Swollen at the tip. superior articular processes; 8, in- 

 ferior articular processes. 



The mammillary and accessory processes 



are little more than tubercles. The spinous processes are thick 

 and broad. The cephalic articular surfaces face medially and to 

 a less extent dorsally ; the caudal articular surfaces face laterally 

 and ventrally. 



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