THE CERVICAL VERTEBRA^: 7 



The transverse processes are two in nmnlter. and jut outwards from the pedieles 

 and lamina' l)etwcen the superior and inferior articular processes. The tip presents 

 an oval facet for articulation with tlie tuhercle «»r the rib. ■ When tlie rilj is in situ, 

 its neck forms with tlie process a costo-transverse foramen. The transverse pro- 

 cesses, in addition to supporting the ribs, afford powerful leverage to muscles. 



THE CERN'ICAL VERTEBRA 



A typical cervical vertebra (from the third to sixth inclusive) ])resents the 

 following characters: The centrum is smaller than in other regions of the colunm, 

 and is of oval shape, the major axis being transverse. The upper surface has its 

 lateral margins raised into prominent lips, whilst the lower surface is somewhat 

 concave, its anterior margin being lipped so as to slightly overlap the anterior 

 surface of the vertebra below. The inferior lateral margins are rounded, and come 

 into relation with the raised edges of the centrum next below. 



The pedicles are directed ol)liquely outwards, and the intervertebral notch is 

 narrower alcove than below. The laminae are long and narrow. The spinous pro- 

 cess is short, and bifid at the extremity. 



Articular processes. — Both the upper and lower articular ]^rocesses are 

 situated at the junction of the pedicle with the lamina' and they form the upper 

 and lower extremities of a small column of ]ion<'. The facets of the upper })ro- 



COSTAL PROCESS — 

 COSTO-TRANSVERSE FORAMEN 

 TRANSVERSE PROCESS 



SUPERIOR ARTICULAR PROCESS 



INFERIOR ARTICULAR PROCESS 



LAMINA 



SPINOUS PROCESS 



PEDICLE 



cesses look backwards and upwards and those of the lower ]>roccsscs forwards and 

 downwards. 



The transverse process presents near its base the costo-transverse foramen 

 for the transmission of the vertebral artery, vein, and a plexus of sympathetic nerves. 

 The process Ijehind the foramen has a shallow groove for the corresponding s]»inal 

 nerve. The extremity of the transverse process is bifid; each arm is terminated by 

 a tubercle referred to as anterior and i)Osterior. The costo-transverse foramen is 

 very characteristic of a cervical vertebra. It is bounded iiUernally by the j)edi(le. 

 posteriorly Ijy the transverse process, anteriorly by the costal process, and exter- 

 nally by the costo-transverse lamella which runs obli(jUely upwards and forwards 

 in the ui)])er vertel)nc and horizontally in the lower. 



Tlie spinal foramen of all the cervical vertel)ra' is large, and somewhat triangular 

 in form. 



Peculiar cervical vertebrae. — The various cervical vertebrae possess distinguish- 

 ing features. The first, second, and seventh have characters so different from tlieir 

 fellows as to render them peculiar. 



The Atlas ok Fihst Cervkal Vertebra 



This vertebra has neither lioily iK.r spinous j.rocess; it is an irregular ring of bone 

 with two thicker portions, the lateral masses, united anteriorly by a bridge, tlie 

 anterior arch, which constitutes one-fifth of tin- entire circumference. This arch 



